Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Public API and common code for kernel->userspace relay file support. |
| 3 | * |
Jesper Juhl | c9b3feb | 2007-07-31 00:39:18 -0700 | [diff] [blame] | 4 | * See Documentation/filesystems/relay.txt for an overview. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 5 | * |
| 6 | * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp |
| 7 | * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com) |
| 8 | * |
| 9 | * Moved to kernel/relay.c by Paul Mundt, 2006. |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 10 | * November 2006 - CPU hotplug support by Mathieu Desnoyers |
| 11 | * (mathieu.desnoyers@polymtl.ca) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 12 | * |
| 13 | * This file is released under the GPL. |
| 14 | */ |
| 15 | #include <linux/errno.h> |
| 16 | #include <linux/stddef.h> |
| 17 | #include <linux/slab.h> |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 18 | #include <linux/export.h> |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 19 | #include <linux/string.h> |
| 20 | #include <linux/relay.h> |
| 21 | #include <linux/vmalloc.h> |
| 22 | #include <linux/mm.h> |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 23 | #include <linux/cpu.h> |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 24 | #include <linux/splice.h> |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 25 | |
| 26 | /* list of open channels, for cpu hotplug */ |
| 27 | static DEFINE_MUTEX(relay_channels_mutex); |
| 28 | static LIST_HEAD(relay_channels); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 29 | |
| 30 | /* |
| 31 | * close() vm_op implementation for relay file mapping. |
| 32 | */ |
| 33 | static void relay_file_mmap_close(struct vm_area_struct *vma) |
| 34 | { |
| 35 | struct rchan_buf *buf = vma->vm_private_data; |
| 36 | buf->chan->cb->buf_unmapped(buf, vma->vm_file); |
| 37 | } |
| 38 | |
| 39 | /* |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 40 | * fault() vm_op implementation for relay file mapping. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 41 | */ |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 42 | static int relay_buf_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 43 | { |
| 44 | struct page *page; |
| 45 | struct rchan_buf *buf = vma->vm_private_data; |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 46 | pgoff_t pgoff = vmf->pgoff; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 47 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 48 | if (!buf) |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 49 | return VM_FAULT_OOM; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 50 | |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 51 | page = vmalloc_to_page(buf->start + (pgoff << PAGE_SHIFT)); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 52 | if (!page) |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 53 | return VM_FAULT_SIGBUS; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 54 | get_page(page); |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 55 | vmf->page = page; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 56 | |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 57 | return 0; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 58 | } |
| 59 | |
| 60 | /* |
| 61 | * vm_ops for relay file mappings. |
| 62 | */ |
Alexey Dobriyan | f0f37e2 | 2009-09-27 22:29:37 +0400 | [diff] [blame] | 63 | static const struct vm_operations_struct relay_file_mmap_ops = { |
Nick Piggin | a1e0961 | 2008-02-06 01:37:34 -0800 | [diff] [blame] | 64 | .fault = relay_buf_fault, |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 65 | .close = relay_file_mmap_close, |
| 66 | }; |
| 67 | |
Masami Hiramatsu | 68ab3d8 | 2008-04-29 01:03:46 -0700 | [diff] [blame] | 68 | /* |
| 69 | * allocate an array of pointers of struct page |
| 70 | */ |
| 71 | static struct page **relay_alloc_page_array(unsigned int n_pages) |
| 72 | { |
Jesper Juhl | 408af87 | 2010-11-04 21:44:41 +0100 | [diff] [blame] | 73 | const size_t pa_size = n_pages * sizeof(struct page *); |
| 74 | if (pa_size > PAGE_SIZE) |
| 75 | return vzalloc(pa_size); |
| 76 | return kzalloc(pa_size, GFP_KERNEL); |
Masami Hiramatsu | 68ab3d8 | 2008-04-29 01:03:46 -0700 | [diff] [blame] | 77 | } |
| 78 | |
| 79 | /* |
| 80 | * free an array of pointers of struct page |
| 81 | */ |
| 82 | static void relay_free_page_array(struct page **array) |
| 83 | { |
Pekka Enberg | 200f1ce | 2015-06-30 14:59:06 -0700 | [diff] [blame] | 84 | kvfree(array); |
Masami Hiramatsu | 68ab3d8 | 2008-04-29 01:03:46 -0700 | [diff] [blame] | 85 | } |
| 86 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 87 | /** |
| 88 | * relay_mmap_buf: - mmap channel buffer to process address space |
| 89 | * @buf: relay channel buffer |
| 90 | * @vma: vm_area_struct describing memory to be mapped |
| 91 | * |
| 92 | * Returns 0 if ok, negative on error |
| 93 | * |
| 94 | * Caller should already have grabbed mmap_sem. |
| 95 | */ |
Adrian Bunk | 01c55ed | 2007-07-19 01:48:32 -0700 | [diff] [blame] | 96 | static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 97 | { |
| 98 | unsigned long length = vma->vm_end - vma->vm_start; |
| 99 | struct file *filp = vma->vm_file; |
| 100 | |
| 101 | if (!buf) |
| 102 | return -EBADF; |
| 103 | |
| 104 | if (length != (unsigned long)buf->chan->alloc_size) |
| 105 | return -EINVAL; |
| 106 | |
| 107 | vma->vm_ops = &relay_file_mmap_ops; |
Nick Piggin | 2f98735 | 2008-02-02 03:08:53 +0100 | [diff] [blame] | 108 | vma->vm_flags |= VM_DONTEXPAND; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 109 | vma->vm_private_data = buf; |
| 110 | buf->chan->cb->buf_mapped(buf, filp); |
| 111 | |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | /** |
| 116 | * relay_alloc_buf - allocate a channel buffer |
| 117 | * @buf: the buffer struct |
| 118 | * @size: total size of the buffer |
| 119 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 120 | * Returns a pointer to the resulting buffer, %NULL if unsuccessful. The |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 121 | * passed in size will get page aligned, if it isn't already. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 122 | */ |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 123 | static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 124 | { |
| 125 | void *mem; |
| 126 | unsigned int i, j, n_pages; |
| 127 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 128 | *size = PAGE_ALIGN(*size); |
| 129 | n_pages = *size >> PAGE_SHIFT; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 130 | |
Masami Hiramatsu | 68ab3d8 | 2008-04-29 01:03:46 -0700 | [diff] [blame] | 131 | buf->page_array = relay_alloc_page_array(n_pages); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 132 | if (!buf->page_array) |
| 133 | return NULL; |
| 134 | |
| 135 | for (i = 0; i < n_pages; i++) { |
| 136 | buf->page_array[i] = alloc_page(GFP_KERNEL); |
| 137 | if (unlikely(!buf->page_array[i])) |
| 138 | goto depopulate; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 139 | set_page_private(buf->page_array[i], (unsigned long)buf); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 140 | } |
| 141 | mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL); |
| 142 | if (!mem) |
| 143 | goto depopulate; |
| 144 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 145 | memset(mem, 0, *size); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 146 | buf->page_count = n_pages; |
| 147 | return mem; |
| 148 | |
| 149 | depopulate: |
| 150 | for (j = 0; j < i; j++) |
| 151 | __free_page(buf->page_array[j]); |
Masami Hiramatsu | 68ab3d8 | 2008-04-29 01:03:46 -0700 | [diff] [blame] | 152 | relay_free_page_array(buf->page_array); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 153 | return NULL; |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * relay_create_buf - allocate and initialize a channel buffer |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 158 | * @chan: the relay channel |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 159 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 160 | * Returns channel buffer if successful, %NULL otherwise. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 161 | */ |
Adrian Bunk | 01c55ed | 2007-07-19 01:48:32 -0700 | [diff] [blame] | 162 | static struct rchan_buf *relay_create_buf(struct rchan *chan) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 163 | { |
Dan Carpenter | f6302f1 | 2012-02-10 09:03:58 +0100 | [diff] [blame] | 164 | struct rchan_buf *buf; |
| 165 | |
David Rientjes | 79dc8f3 | 2018-02-21 14:45:32 -0800 | [diff] [blame] | 166 | if (chan->n_subbufs > KMALLOC_MAX_SIZE / sizeof(size_t *)) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 167 | return NULL; |
| 168 | |
Dan Carpenter | f6302f1 | 2012-02-10 09:03:58 +0100 | [diff] [blame] | 169 | buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL); |
| 170 | if (!buf) |
| 171 | return NULL; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 172 | buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL); |
| 173 | if (!buf->padding) |
| 174 | goto free_buf; |
| 175 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 176 | buf->start = relay_alloc_buf(buf, &chan->alloc_size); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 177 | if (!buf->start) |
| 178 | goto free_buf; |
| 179 | |
| 180 | buf->chan = chan; |
| 181 | kref_get(&buf->chan->kref); |
| 182 | return buf; |
| 183 | |
| 184 | free_buf: |
| 185 | kfree(buf->padding); |
| 186 | kfree(buf); |
| 187 | return NULL; |
| 188 | } |
| 189 | |
| 190 | /** |
| 191 | * relay_destroy_channel - free the channel struct |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 192 | * @kref: target kernel reference that contains the relay channel |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 193 | * |
| 194 | * Should only be called from kref_put(). |
| 195 | */ |
Adrian Bunk | 01c55ed | 2007-07-19 01:48:32 -0700 | [diff] [blame] | 196 | static void relay_destroy_channel(struct kref *kref) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 197 | { |
| 198 | struct rchan *chan = container_of(kref, struct rchan, kref); |
| 199 | kfree(chan); |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * relay_destroy_buf - destroy an rchan_buf struct and associated buffer |
| 204 | * @buf: the buffer struct |
| 205 | */ |
Adrian Bunk | 01c55ed | 2007-07-19 01:48:32 -0700 | [diff] [blame] | 206 | static void relay_destroy_buf(struct rchan_buf *buf) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 207 | { |
| 208 | struct rchan *chan = buf->chan; |
| 209 | unsigned int i; |
| 210 | |
| 211 | if (likely(buf->start)) { |
| 212 | vunmap(buf->start); |
| 213 | for (i = 0; i < buf->page_count; i++) |
| 214 | __free_page(buf->page_array[i]); |
Masami Hiramatsu | 68ab3d8 | 2008-04-29 01:03:46 -0700 | [diff] [blame] | 215 | relay_free_page_array(buf->page_array); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 216 | } |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 217 | *per_cpu_ptr(chan->buf, buf->cpu) = NULL; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 218 | kfree(buf->padding); |
| 219 | kfree(buf); |
| 220 | kref_put(&chan->kref, relay_destroy_channel); |
| 221 | } |
| 222 | |
| 223 | /** |
| 224 | * relay_remove_buf - remove a channel buffer |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 225 | * @kref: target kernel reference that contains the relay buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 226 | * |
Masanari Iida | e227867 | 2014-02-18 22:54:36 +0900 | [diff] [blame] | 227 | * Removes the file from the filesystem, which also frees the |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 228 | * rchan_buf_struct and the channel buffer. Should only be called from |
| 229 | * kref_put(). |
| 230 | */ |
Adrian Bunk | 01c55ed | 2007-07-19 01:48:32 -0700 | [diff] [blame] | 231 | static void relay_remove_buf(struct kref *kref) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 232 | { |
| 233 | struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 234 | relay_destroy_buf(buf); |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * relay_buf_empty - boolean, is the channel buffer empty? |
| 239 | * @buf: channel buffer |
| 240 | * |
| 241 | * Returns 1 if the buffer is empty, 0 otherwise. |
| 242 | */ |
Adrian Bunk | 01c55ed | 2007-07-19 01:48:32 -0700 | [diff] [blame] | 243 | static int relay_buf_empty(struct rchan_buf *buf) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 244 | { |
| 245 | return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1; |
| 246 | } |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 247 | |
| 248 | /** |
| 249 | * relay_buf_full - boolean, is the channel buffer full? |
| 250 | * @buf: channel buffer |
| 251 | * |
| 252 | * Returns 1 if the buffer is full, 0 otherwise. |
| 253 | */ |
| 254 | int relay_buf_full(struct rchan_buf *buf) |
| 255 | { |
| 256 | size_t ready = buf->subbufs_produced - buf->subbufs_consumed; |
| 257 | return (ready >= buf->chan->n_subbufs) ? 1 : 0; |
| 258 | } |
| 259 | EXPORT_SYMBOL_GPL(relay_buf_full); |
| 260 | |
| 261 | /* |
| 262 | * High-level relay kernel API and associated functions. |
| 263 | */ |
| 264 | |
| 265 | /* |
| 266 | * rchan_callback implementations defining default channel behavior. Used |
| 267 | * in place of corresponding NULL values in client callback struct. |
| 268 | */ |
| 269 | |
| 270 | /* |
| 271 | * subbuf_start() default callback. Does nothing. |
| 272 | */ |
| 273 | static int subbuf_start_default_callback (struct rchan_buf *buf, |
| 274 | void *subbuf, |
| 275 | void *prev_subbuf, |
| 276 | size_t prev_padding) |
| 277 | { |
| 278 | if (relay_buf_full(buf)) |
| 279 | return 0; |
| 280 | |
| 281 | return 1; |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * buf_mapped() default callback. Does nothing. |
| 286 | */ |
| 287 | static void buf_mapped_default_callback(struct rchan_buf *buf, |
| 288 | struct file *filp) |
| 289 | { |
| 290 | } |
| 291 | |
| 292 | /* |
| 293 | * buf_unmapped() default callback. Does nothing. |
| 294 | */ |
| 295 | static void buf_unmapped_default_callback(struct rchan_buf *buf, |
| 296 | struct file *filp) |
| 297 | { |
| 298 | } |
| 299 | |
| 300 | /* |
| 301 | * create_buf_file_create() default callback. Does nothing. |
| 302 | */ |
| 303 | static struct dentry *create_buf_file_default_callback(const char *filename, |
| 304 | struct dentry *parent, |
Al Viro | f4ae40a | 2011-07-24 04:33:43 -0400 | [diff] [blame] | 305 | umode_t mode, |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 306 | struct rchan_buf *buf, |
| 307 | int *is_global) |
| 308 | { |
| 309 | return NULL; |
| 310 | } |
| 311 | |
| 312 | /* |
| 313 | * remove_buf_file() default callback. Does nothing. |
| 314 | */ |
| 315 | static int remove_buf_file_default_callback(struct dentry *dentry) |
| 316 | { |
| 317 | return -EINVAL; |
| 318 | } |
| 319 | |
| 320 | /* relay channel default callbacks */ |
| 321 | static struct rchan_callbacks default_channel_callbacks = { |
| 322 | .subbuf_start = subbuf_start_default_callback, |
| 323 | .buf_mapped = buf_mapped_default_callback, |
| 324 | .buf_unmapped = buf_unmapped_default_callback, |
| 325 | .create_buf_file = create_buf_file_default_callback, |
| 326 | .remove_buf_file = remove_buf_file_default_callback, |
| 327 | }; |
| 328 | |
| 329 | /** |
| 330 | * wakeup_readers - wake up readers waiting on a channel |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 331 | * @work: contains the channel buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 332 | * |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 333 | * This is the function used to defer reader waking |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 334 | */ |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 335 | static void wakeup_readers(struct irq_work *work) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 336 | { |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 337 | struct rchan_buf *buf; |
| 338 | |
| 339 | buf = container_of(work, struct rchan_buf, wakeup_work); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 340 | wake_up_interruptible(&buf->read_wait); |
| 341 | } |
| 342 | |
| 343 | /** |
| 344 | * __relay_reset - reset a channel buffer |
| 345 | * @buf: the channel buffer |
| 346 | * @init: 1 if this is a first-time initialization |
| 347 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 348 | * See relay_reset() for description of effect. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 349 | */ |
Andrew Morton | 192636a | 2006-12-22 01:11:30 -0800 | [diff] [blame] | 350 | static void __relay_reset(struct rchan_buf *buf, unsigned int init) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 351 | { |
| 352 | size_t i; |
| 353 | |
| 354 | if (init) { |
| 355 | init_waitqueue_head(&buf->read_wait); |
| 356 | kref_init(&buf->kref); |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 357 | init_irq_work(&buf->wakeup_work, wakeup_readers); |
| 358 | } else { |
| 359 | irq_work_sync(&buf->wakeup_work); |
| 360 | } |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 361 | |
| 362 | buf->subbufs_produced = 0; |
| 363 | buf->subbufs_consumed = 0; |
| 364 | buf->bytes_consumed = 0; |
| 365 | buf->finalized = 0; |
| 366 | buf->data = buf->start; |
| 367 | buf->offset = 0; |
| 368 | |
| 369 | for (i = 0; i < buf->chan->n_subbufs; i++) |
| 370 | buf->padding[i] = 0; |
| 371 | |
| 372 | buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0); |
| 373 | } |
| 374 | |
| 375 | /** |
| 376 | * relay_reset - reset the channel |
| 377 | * @chan: the channel |
| 378 | * |
| 379 | * This has the effect of erasing all data from all channel buffers |
| 380 | * and restarting the channel in its initial state. The buffers |
| 381 | * are not freed, so any mappings are still in effect. |
| 382 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 383 | * NOTE. Care should be taken that the channel isn't actually |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 384 | * being used by anything when this call is made. |
| 385 | */ |
| 386 | void relay_reset(struct rchan *chan) |
| 387 | { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 388 | struct rchan_buf *buf; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 389 | unsigned int i; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 390 | |
| 391 | if (!chan) |
| 392 | return; |
| 393 | |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 394 | if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) { |
| 395 | __relay_reset(buf, 0); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 396 | return; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 397 | } |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 398 | |
| 399 | mutex_lock(&relay_channels_mutex); |
Lai Jiangshan | 98ba403 | 2008-11-14 10:44:59 +0100 | [diff] [blame] | 400 | for_each_possible_cpu(i) |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 401 | if ((buf = *per_cpu_ptr(chan->buf, i))) |
| 402 | __relay_reset(buf, 0); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 403 | mutex_unlock(&relay_channels_mutex); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 404 | } |
| 405 | EXPORT_SYMBOL_GPL(relay_reset); |
| 406 | |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 407 | static inline void relay_set_buf_dentry(struct rchan_buf *buf, |
| 408 | struct dentry *dentry) |
| 409 | { |
| 410 | buf->dentry = dentry; |
David Howells | 7682c91 | 2015-03-17 22:26:16 +0000 | [diff] [blame] | 411 | d_inode(buf->dentry)->i_size = buf->early_bytes; |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 412 | } |
| 413 | |
| 414 | static struct dentry *relay_create_buf_file(struct rchan *chan, |
| 415 | struct rchan_buf *buf, |
| 416 | unsigned int cpu) |
| 417 | { |
| 418 | struct dentry *dentry; |
| 419 | char *tmpname; |
| 420 | |
| 421 | tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL); |
| 422 | if (!tmpname) |
| 423 | return NULL; |
| 424 | snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu); |
| 425 | |
| 426 | /* Create file in fs */ |
| 427 | dentry = chan->cb->create_buf_file(tmpname, chan->parent, |
| 428 | S_IRUSR, buf, |
| 429 | &chan->is_global); |
| 430 | |
| 431 | kfree(tmpname); |
| 432 | |
| 433 | return dentry; |
| 434 | } |
| 435 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 436 | /* |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 437 | * relay_open_buf - create a new relay channel buffer |
| 438 | * |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 439 | * used by relay_open() and CPU hotplug. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 440 | */ |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 441 | static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 442 | { |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 443 | struct rchan_buf *buf = NULL; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 444 | struct dentry *dentry; |
| 445 | |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 446 | if (chan->is_global) |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 447 | return *per_cpu_ptr(chan->buf, 0); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 448 | |
| 449 | buf = relay_create_buf(chan); |
| 450 | if (!buf) |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 451 | return NULL; |
| 452 | |
| 453 | if (chan->has_base_filename) { |
| 454 | dentry = relay_create_buf_file(chan, buf, cpu); |
| 455 | if (!dentry) |
| 456 | goto free_buf; |
| 457 | relay_set_buf_dentry(buf, dentry); |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 458 | } else { |
| 459 | /* Only retrieve global info, nothing more, nothing less */ |
| 460 | dentry = chan->cb->create_buf_file(NULL, NULL, |
| 461 | S_IRUSR, buf, |
| 462 | &chan->is_global); |
| 463 | if (WARN_ON(dentry)) |
| 464 | goto free_buf; |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 465 | } |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 466 | |
| 467 | buf->cpu = cpu; |
| 468 | __relay_reset(buf, 1); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 469 | |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 470 | if(chan->is_global) { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 471 | *per_cpu_ptr(chan->buf, 0) = buf; |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 472 | buf->cpu = 0; |
| 473 | } |
| 474 | |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 475 | return buf; |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 476 | |
| 477 | free_buf: |
| 478 | relay_destroy_buf(buf); |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 479 | return NULL; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 480 | } |
| 481 | |
| 482 | /** |
| 483 | * relay_close_buf - close a channel buffer |
| 484 | * @buf: channel buffer |
| 485 | * |
| 486 | * Marks the buffer finalized and restores the default callbacks. |
| 487 | * The channel buffer and channel buffer data structure are then freed |
| 488 | * automatically when the last reference is given up. |
| 489 | */ |
Andrew Morton | 192636a | 2006-12-22 01:11:30 -0800 | [diff] [blame] | 490 | static void relay_close_buf(struct rchan_buf *buf) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 491 | { |
| 492 | buf->finalized = 1; |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 493 | irq_work_sync(&buf->wakeup_work); |
Dmitry Monakhov | b8d4a5b | 2013-04-22 11:41:41 +0400 | [diff] [blame] | 494 | buf->chan->cb->remove_buf_file(buf->dentry); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 495 | kref_put(&buf->kref, relay_remove_buf); |
| 496 | } |
| 497 | |
Andrew Morton | 192636a | 2006-12-22 01:11:30 -0800 | [diff] [blame] | 498 | static void setup_callbacks(struct rchan *chan, |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 499 | struct rchan_callbacks *cb) |
| 500 | { |
| 501 | if (!cb) { |
| 502 | chan->cb = &default_channel_callbacks; |
| 503 | return; |
| 504 | } |
| 505 | |
| 506 | if (!cb->subbuf_start) |
| 507 | cb->subbuf_start = subbuf_start_default_callback; |
| 508 | if (!cb->buf_mapped) |
| 509 | cb->buf_mapped = buf_mapped_default_callback; |
| 510 | if (!cb->buf_unmapped) |
| 511 | cb->buf_unmapped = buf_unmapped_default_callback; |
| 512 | if (!cb->create_buf_file) |
| 513 | cb->create_buf_file = create_buf_file_default_callback; |
| 514 | if (!cb->remove_buf_file) |
| 515 | cb->remove_buf_file = remove_buf_file_default_callback; |
| 516 | chan->cb = cb; |
| 517 | } |
| 518 | |
Richard Weinberger | e6d4989 | 2016-08-18 14:57:17 +0200 | [diff] [blame] | 519 | int relay_prepare_cpu(unsigned int cpu) |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 520 | { |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 521 | struct rchan *chan; |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 522 | struct rchan_buf *buf; |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 523 | |
Richard Weinberger | e6d4989 | 2016-08-18 14:57:17 +0200 | [diff] [blame] | 524 | mutex_lock(&relay_channels_mutex); |
| 525 | list_for_each_entry(chan, &relay_channels, list) { |
| 526 | if ((buf = *per_cpu_ptr(chan->buf, cpu))) |
| 527 | continue; |
| 528 | buf = relay_open_buf(chan, cpu); |
| 529 | if (!buf) { |
| 530 | pr_err("relay: cpu %d buffer creation failed\n", cpu); |
| 531 | mutex_unlock(&relay_channels_mutex); |
| 532 | return -ENOMEM; |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 533 | } |
Richard Weinberger | e6d4989 | 2016-08-18 14:57:17 +0200 | [diff] [blame] | 534 | *per_cpu_ptr(chan->buf, cpu) = buf; |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 535 | } |
Richard Weinberger | e6d4989 | 2016-08-18 14:57:17 +0200 | [diff] [blame] | 536 | mutex_unlock(&relay_channels_mutex); |
| 537 | return 0; |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 538 | } |
| 539 | |
| 540 | /** |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 541 | * relay_open - create a new relay channel |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 542 | * @base_filename: base name of files to create, %NULL for buffering only |
| 543 | * @parent: dentry of parent directory, %NULL for root directory or buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 544 | * @subbuf_size: size of sub-buffers |
| 545 | * @n_subbufs: number of sub-buffers |
| 546 | * @cb: client callback functions |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 547 | * @private_data: user-defined data |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 548 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 549 | * Returns channel pointer if successful, %NULL otherwise. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 550 | * |
| 551 | * Creates a channel buffer for each cpu using the sizes and |
| 552 | * attributes specified. The created channel buffer files |
| 553 | * will be named base_filename0...base_filenameN-1. File |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 554 | * permissions will be %S_IRUSR. |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 555 | * |
| 556 | * If opening a buffer (@parent = NULL) that you later wish to register |
| 557 | * in a filesystem, call relay_late_setup_files() once the @parent dentry |
| 558 | * is available. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 559 | */ |
| 560 | struct rchan *relay_open(const char *base_filename, |
| 561 | struct dentry *parent, |
| 562 | size_t subbuf_size, |
| 563 | size_t n_subbufs, |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 564 | struct rchan_callbacks *cb, |
| 565 | void *private_data) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 566 | { |
| 567 | unsigned int i; |
| 568 | struct rchan *chan; |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 569 | struct rchan_buf *buf; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 570 | |
| 571 | if (!(subbuf_size && n_subbufs)) |
| 572 | return NULL; |
Dan Carpenter | f6302f1 | 2012-02-10 09:03:58 +0100 | [diff] [blame] | 573 | if (subbuf_size > UINT_MAX / n_subbufs) |
| 574 | return NULL; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 575 | |
Robert P. J. Day | cd86128 | 2006-12-13 00:34:52 -0800 | [diff] [blame] | 576 | chan = kzalloc(sizeof(struct rchan), GFP_KERNEL); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 577 | if (!chan) |
| 578 | return NULL; |
| 579 | |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 580 | chan->buf = alloc_percpu(struct rchan_buf *); |
Daniel Axtens | d1774b0 | 2020-06-04 16:51:27 -0700 | [diff] [blame] | 581 | if (!chan->buf) { |
| 582 | kfree(chan); |
| 583 | return NULL; |
| 584 | } |
| 585 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 586 | chan->version = RELAYFS_CHANNEL_VERSION; |
| 587 | chan->n_subbufs = n_subbufs; |
| 588 | chan->subbuf_size = subbuf_size; |
zhangwei(Jovi) | a05342cb | 2013-04-30 15:28:41 -0700 | [diff] [blame] | 589 | chan->alloc_size = PAGE_ALIGN(subbuf_size * n_subbufs); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 590 | chan->parent = parent; |
| 591 | chan->private_data = private_data; |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 592 | if (base_filename) { |
| 593 | chan->has_base_filename = 1; |
| 594 | strlcpy(chan->base_filename, base_filename, NAME_MAX); |
| 595 | } |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 596 | setup_callbacks(chan, cb); |
| 597 | kref_init(&chan->kref); |
| 598 | |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 599 | mutex_lock(&relay_channels_mutex); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 600 | for_each_online_cpu(i) { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 601 | buf = relay_open_buf(chan, i); |
| 602 | if (!buf) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 603 | goto free_bufs; |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 604 | *per_cpu_ptr(chan->buf, i) = buf; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 605 | } |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 606 | list_add(&chan->list, &relay_channels); |
| 607 | mutex_unlock(&relay_channels_mutex); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 608 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 609 | return chan; |
| 610 | |
| 611 | free_bufs: |
Lai Jiangshan | 98ba403 | 2008-11-14 10:44:59 +0100 | [diff] [blame] | 612 | for_each_possible_cpu(i) { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 613 | if ((buf = *per_cpu_ptr(chan->buf, i))) |
| 614 | relay_close_buf(buf); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 615 | } |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 616 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 617 | kref_put(&chan->kref, relay_destroy_channel); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 618 | mutex_unlock(&relay_channels_mutex); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 619 | return NULL; |
| 620 | } |
| 621 | EXPORT_SYMBOL_GPL(relay_open); |
| 622 | |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 623 | struct rchan_percpu_buf_dispatcher { |
| 624 | struct rchan_buf *buf; |
| 625 | struct dentry *dentry; |
| 626 | }; |
| 627 | |
| 628 | /* Called in atomic context. */ |
| 629 | static void __relay_set_buf_dentry(void *info) |
| 630 | { |
| 631 | struct rchan_percpu_buf_dispatcher *p = info; |
| 632 | |
| 633 | relay_set_buf_dentry(p->buf, p->dentry); |
| 634 | } |
| 635 | |
| 636 | /** |
| 637 | * relay_late_setup_files - triggers file creation |
| 638 | * @chan: channel to operate on |
| 639 | * @base_filename: base name of files to create |
| 640 | * @parent: dentry of parent directory, %NULL for root directory |
| 641 | * |
| 642 | * Returns 0 if successful, non-zero otherwise. |
| 643 | * |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 644 | * Use to setup files for a previously buffer-only channel created |
| 645 | * by relay_open() with a NULL parent dentry. |
| 646 | * |
| 647 | * For example, this is useful for perfomring early tracing in kernel, |
| 648 | * before VFS is up and then exposing the early results once the dentry |
| 649 | * is available. |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 650 | */ |
| 651 | int relay_late_setup_files(struct rchan *chan, |
| 652 | const char *base_filename, |
| 653 | struct dentry *parent) |
| 654 | { |
| 655 | int err = 0; |
| 656 | unsigned int i, curr_cpu; |
| 657 | unsigned long flags; |
| 658 | struct dentry *dentry; |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 659 | struct rchan_buf *buf; |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 660 | struct rchan_percpu_buf_dispatcher disp; |
| 661 | |
| 662 | if (!chan || !base_filename) |
| 663 | return -EINVAL; |
| 664 | |
| 665 | strlcpy(chan->base_filename, base_filename, NAME_MAX); |
| 666 | |
| 667 | mutex_lock(&relay_channels_mutex); |
| 668 | /* Is chan already set up? */ |
Jiri Slaby | b786c6a | 2009-01-17 12:04:36 +0100 | [diff] [blame] | 669 | if (unlikely(chan->has_base_filename)) { |
| 670 | mutex_unlock(&relay_channels_mutex); |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 671 | return -EEXIST; |
Jiri Slaby | b786c6a | 2009-01-17 12:04:36 +0100 | [diff] [blame] | 672 | } |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 673 | chan->has_base_filename = 1; |
| 674 | chan->parent = parent; |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 675 | |
| 676 | if (chan->is_global) { |
| 677 | err = -EINVAL; |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 678 | buf = *per_cpu_ptr(chan->buf, 0); |
| 679 | if (!WARN_ON_ONCE(!buf)) { |
| 680 | dentry = relay_create_buf_file(chan, buf, 0); |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 681 | if (dentry && !WARN_ON_ONCE(!chan->is_global)) { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 682 | relay_set_buf_dentry(buf, dentry); |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 683 | err = 0; |
| 684 | } |
| 685 | } |
| 686 | mutex_unlock(&relay_channels_mutex); |
| 687 | return err; |
| 688 | } |
| 689 | |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 690 | curr_cpu = get_cpu(); |
| 691 | /* |
| 692 | * The CPU hotplug notifier ran before us and created buffers with |
| 693 | * no files associated. So it's safe to call relay_setup_buf_file() |
| 694 | * on all currently online CPUs. |
| 695 | */ |
| 696 | for_each_online_cpu(i) { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 697 | buf = *per_cpu_ptr(chan->buf, i); |
| 698 | if (unlikely(!buf)) { |
Ingo Molnar | 7a51cff | 2008-12-29 16:03:40 +0100 | [diff] [blame] | 699 | WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n"); |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 700 | err = -EINVAL; |
| 701 | break; |
| 702 | } |
| 703 | |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 704 | dentry = relay_create_buf_file(chan, buf, i); |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 705 | if (unlikely(!dentry)) { |
| 706 | err = -EINVAL; |
| 707 | break; |
| 708 | } |
| 709 | |
| 710 | if (curr_cpu == i) { |
| 711 | local_irq_save(flags); |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 712 | relay_set_buf_dentry(buf, dentry); |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 713 | local_irq_restore(flags); |
| 714 | } else { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 715 | disp.buf = buf; |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 716 | disp.dentry = dentry; |
| 717 | smp_mb(); |
| 718 | /* relay_channels_mutex must be held, so wait. */ |
| 719 | err = smp_call_function_single(i, |
| 720 | __relay_set_buf_dentry, |
| 721 | &disp, 1); |
| 722 | } |
| 723 | if (unlikely(err)) |
| 724 | break; |
| 725 | } |
| 726 | put_cpu(); |
| 727 | mutex_unlock(&relay_channels_mutex); |
| 728 | |
| 729 | return err; |
| 730 | } |
Akash Goel | 59dbb2a | 2016-08-02 14:07:18 -0700 | [diff] [blame] | 731 | EXPORT_SYMBOL_GPL(relay_late_setup_files); |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 732 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 733 | /** |
| 734 | * relay_switch_subbuf - switch to a new sub-buffer |
| 735 | * @buf: channel buffer |
| 736 | * @length: size of current event |
| 737 | * |
| 738 | * Returns either the length passed in or 0 if full. |
| 739 | * |
| 740 | * Performs sub-buffer-switch tasks such as invoking callbacks, |
| 741 | * updating padding counts, waking up readers, etc. |
| 742 | */ |
| 743 | size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length) |
| 744 | { |
| 745 | void *old, *new; |
| 746 | size_t old_subbuf, new_subbuf; |
| 747 | |
| 748 | if (unlikely(length > buf->chan->subbuf_size)) |
| 749 | goto toobig; |
| 750 | |
| 751 | if (buf->offset != buf->chan->subbuf_size + 1) { |
| 752 | buf->prev_padding = buf->chan->subbuf_size - buf->offset; |
| 753 | old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; |
| 754 | buf->padding[old_subbuf] = buf->prev_padding; |
| 755 | buf->subbufs_produced++; |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 756 | if (buf->dentry) |
David Howells | 7682c91 | 2015-03-17 22:26:16 +0000 | [diff] [blame] | 757 | d_inode(buf->dentry)->i_size += |
Eduard - Gabriel Munteanu | 20d8b67 | 2008-07-25 19:45:12 -0700 | [diff] [blame] | 758 | buf->chan->subbuf_size - |
| 759 | buf->padding[old_subbuf]; |
| 760 | else |
| 761 | buf->early_bytes += buf->chan->subbuf_size - |
| 762 | buf->padding[old_subbuf]; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 763 | smp_mb(); |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 764 | if (waitqueue_active(&buf->read_wait)) { |
Tom Zanussi | 7c9cb38 | 2007-05-09 02:34:01 -0700 | [diff] [blame] | 765 | /* |
| 766 | * Calling wake_up_interruptible() from here |
| 767 | * will deadlock if we happen to be logging |
| 768 | * from the scheduler (trying to re-grab |
| 769 | * rq->lock), so defer it. |
| 770 | */ |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 771 | irq_work_queue(&buf->wakeup_work); |
| 772 | } |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 773 | } |
| 774 | |
| 775 | old = buf->data; |
| 776 | new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs; |
| 777 | new = buf->start + new_subbuf * buf->chan->subbuf_size; |
| 778 | buf->offset = 0; |
| 779 | if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) { |
| 780 | buf->offset = buf->chan->subbuf_size + 1; |
| 781 | return 0; |
| 782 | } |
| 783 | buf->data = new; |
| 784 | buf->padding[new_subbuf] = 0; |
| 785 | |
| 786 | if (unlikely(length + buf->offset > buf->chan->subbuf_size)) |
| 787 | goto toobig; |
| 788 | |
| 789 | return length; |
| 790 | |
| 791 | toobig: |
| 792 | buf->chan->last_toobig = length; |
| 793 | return 0; |
| 794 | } |
| 795 | EXPORT_SYMBOL_GPL(relay_switch_subbuf); |
| 796 | |
| 797 | /** |
| 798 | * relay_subbufs_consumed - update the buffer's sub-buffers-consumed count |
| 799 | * @chan: the channel |
| 800 | * @cpu: the cpu associated with the channel buffer to update |
| 801 | * @subbufs_consumed: number of sub-buffers to add to current buf's count |
| 802 | * |
| 803 | * Adds to the channel buffer's consumed sub-buffer count. |
| 804 | * subbufs_consumed should be the number of sub-buffers newly consumed, |
| 805 | * not the total consumed. |
| 806 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 807 | * NOTE. Kernel clients don't need to call this function if the channel |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 808 | * mode is 'overwrite'. |
| 809 | */ |
| 810 | void relay_subbufs_consumed(struct rchan *chan, |
| 811 | unsigned int cpu, |
| 812 | size_t subbufs_consumed) |
| 813 | { |
| 814 | struct rchan_buf *buf; |
| 815 | |
Dan Carpenter | c4c11b4 | 2016-12-14 15:05:38 -0800 | [diff] [blame] | 816 | if (!chan || cpu >= NR_CPUS) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 817 | return; |
| 818 | |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 819 | buf = *per_cpu_ptr(chan->buf, cpu); |
Dan Carpenter | c4c11b4 | 2016-12-14 15:05:38 -0800 | [diff] [blame] | 820 | if (!buf || subbufs_consumed > chan->n_subbufs) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 821 | return; |
| 822 | |
Aravind Srinivasan | 2c53d91 | 2009-04-02 16:58:59 -0700 | [diff] [blame] | 823 | if (subbufs_consumed > buf->subbufs_produced - buf->subbufs_consumed) |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 824 | buf->subbufs_consumed = buf->subbufs_produced; |
Aravind Srinivasan | 2c53d91 | 2009-04-02 16:58:59 -0700 | [diff] [blame] | 825 | else |
| 826 | buf->subbufs_consumed += subbufs_consumed; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 827 | } |
| 828 | EXPORT_SYMBOL_GPL(relay_subbufs_consumed); |
| 829 | |
| 830 | /** |
| 831 | * relay_close - close the channel |
| 832 | * @chan: the channel |
| 833 | * |
| 834 | * Closes all channel buffers and frees the channel. |
| 835 | */ |
| 836 | void relay_close(struct rchan *chan) |
| 837 | { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 838 | struct rchan_buf *buf; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 839 | unsigned int i; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 840 | |
| 841 | if (!chan) |
| 842 | return; |
| 843 | |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 844 | mutex_lock(&relay_channels_mutex); |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 845 | if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) |
| 846 | relay_close_buf(buf); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 847 | else |
| 848 | for_each_possible_cpu(i) |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 849 | if ((buf = *per_cpu_ptr(chan->buf, i))) |
| 850 | relay_close_buf(buf); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 851 | |
| 852 | if (chan->last_toobig) |
| 853 | printk(KERN_WARNING "relay: one or more items not logged " |
| 854 | "[item size (%Zd) > sub-buffer size (%Zd)]\n", |
| 855 | chan->last_toobig, chan->subbuf_size); |
| 856 | |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 857 | list_del(&chan->list); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 858 | kref_put(&chan->kref, relay_destroy_channel); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 859 | mutex_unlock(&relay_channels_mutex); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 860 | } |
| 861 | EXPORT_SYMBOL_GPL(relay_close); |
| 862 | |
| 863 | /** |
| 864 | * relay_flush - close the channel |
| 865 | * @chan: the channel |
| 866 | * |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 867 | * Flushes all channel buffers, i.e. forces buffer switch. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 868 | */ |
| 869 | void relay_flush(struct rchan *chan) |
| 870 | { |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 871 | struct rchan_buf *buf; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 872 | unsigned int i; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 873 | |
| 874 | if (!chan) |
| 875 | return; |
| 876 | |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 877 | if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) { |
| 878 | relay_switch_subbuf(buf, 0); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 879 | return; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 880 | } |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 881 | |
| 882 | mutex_lock(&relay_channels_mutex); |
| 883 | for_each_possible_cpu(i) |
Akash Goel | 017c59c | 2016-09-02 21:47:38 +0200 | [diff] [blame] | 884 | if ((buf = *per_cpu_ptr(chan->buf, i))) |
| 885 | relay_switch_subbuf(buf, 0); |
Mathieu Desnoyers | 23c8875 | 2007-02-10 01:45:05 -0800 | [diff] [blame] | 886 | mutex_unlock(&relay_channels_mutex); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 887 | } |
| 888 | EXPORT_SYMBOL_GPL(relay_flush); |
| 889 | |
| 890 | /** |
| 891 | * relay_file_open - open file op for relay files |
| 892 | * @inode: the inode |
| 893 | * @filp: the file |
| 894 | * |
| 895 | * Increments the channel buffer refcount. |
| 896 | */ |
| 897 | static int relay_file_open(struct inode *inode, struct file *filp) |
| 898 | { |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 899 | struct rchan_buf *buf = inode->i_private; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 900 | kref_get(&buf->kref); |
| 901 | filp->private_data = buf; |
| 902 | |
Lai Jiangshan | 37529fe | 2008-03-26 12:01:28 +0100 | [diff] [blame] | 903 | return nonseekable_open(inode, filp); |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 904 | } |
| 905 | |
| 906 | /** |
| 907 | * relay_file_mmap - mmap file op for relay files |
| 908 | * @filp: the file |
| 909 | * @vma: the vma describing what to map |
| 910 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 911 | * Calls upon relay_mmap_buf() to map the file into user space. |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 912 | */ |
| 913 | static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma) |
| 914 | { |
| 915 | struct rchan_buf *buf = filp->private_data; |
| 916 | return relay_mmap_buf(buf, vma); |
| 917 | } |
| 918 | |
| 919 | /** |
| 920 | * relay_file_poll - poll file op for relay files |
| 921 | * @filp: the file |
| 922 | * @wait: poll table |
| 923 | * |
| 924 | * Poll implemention. |
| 925 | */ |
| 926 | static unsigned int relay_file_poll(struct file *filp, poll_table *wait) |
| 927 | { |
| 928 | unsigned int mask = 0; |
| 929 | struct rchan_buf *buf = filp->private_data; |
| 930 | |
| 931 | if (buf->finalized) |
| 932 | return POLLERR; |
| 933 | |
| 934 | if (filp->f_mode & FMODE_READ) { |
| 935 | poll_wait(filp, &buf->read_wait, wait); |
| 936 | if (!relay_buf_empty(buf)) |
| 937 | mask |= POLLIN | POLLRDNORM; |
| 938 | } |
| 939 | |
| 940 | return mask; |
| 941 | } |
| 942 | |
| 943 | /** |
| 944 | * relay_file_release - release file op for relay files |
| 945 | * @inode: the inode |
| 946 | * @filp: the file |
| 947 | * |
| 948 | * Decrements the channel refcount, as the filesystem is |
| 949 | * no longer using it. |
| 950 | */ |
| 951 | static int relay_file_release(struct inode *inode, struct file *filp) |
| 952 | { |
| 953 | struct rchan_buf *buf = filp->private_data; |
| 954 | kref_put(&buf->kref, relay_remove_buf); |
| 955 | |
| 956 | return 0; |
| 957 | } |
| 958 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 959 | /* |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 960 | * relay_file_read_consume - update the consumed count for the buffer |
| 961 | */ |
| 962 | static void relay_file_read_consume(struct rchan_buf *buf, |
| 963 | size_t read_pos, |
| 964 | size_t bytes_consumed) |
| 965 | { |
| 966 | size_t subbuf_size = buf->chan->subbuf_size; |
| 967 | size_t n_subbufs = buf->chan->n_subbufs; |
| 968 | size_t read_subbuf; |
| 969 | |
Tom Zanussi | 3219445 | 2008-08-05 13:01:10 -0700 | [diff] [blame] | 970 | if (buf->subbufs_produced == buf->subbufs_consumed && |
| 971 | buf->offset == buf->bytes_consumed) |
| 972 | return; |
| 973 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 974 | if (buf->bytes_consumed + bytes_consumed > subbuf_size) { |
| 975 | relay_subbufs_consumed(buf->chan, buf->cpu, 1); |
| 976 | buf->bytes_consumed = 0; |
| 977 | } |
| 978 | |
| 979 | buf->bytes_consumed += bytes_consumed; |
Masami Hiramatsu | a66e356 | 2007-06-27 14:10:04 -0700 | [diff] [blame] | 980 | if (!read_pos) |
| 981 | read_subbuf = buf->subbufs_consumed % n_subbufs; |
| 982 | else |
| 983 | read_subbuf = read_pos / buf->chan->subbuf_size; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 984 | if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) { |
| 985 | if ((read_subbuf == buf->subbufs_produced % n_subbufs) && |
| 986 | (buf->offset == subbuf_size)) |
| 987 | return; |
| 988 | relay_subbufs_consumed(buf->chan, buf->cpu, 1); |
| 989 | buf->bytes_consumed = 0; |
| 990 | } |
| 991 | } |
| 992 | |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 993 | /* |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 994 | * relay_file_read_avail - boolean, are there unconsumed bytes available? |
| 995 | */ |
| 996 | static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos) |
| 997 | { |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 998 | size_t subbuf_size = buf->chan->subbuf_size; |
| 999 | size_t n_subbufs = buf->chan->n_subbufs; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1000 | size_t produced = buf->subbufs_produced; |
| 1001 | size_t consumed = buf->subbufs_consumed; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1002 | |
| 1003 | relay_file_read_consume(buf, read_pos, 0); |
| 1004 | |
Tom Zanussi | 3219445 | 2008-08-05 13:01:10 -0700 | [diff] [blame] | 1005 | consumed = buf->subbufs_consumed; |
| 1006 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1007 | if (unlikely(buf->offset > subbuf_size)) { |
| 1008 | if (produced == consumed) |
| 1009 | return 0; |
| 1010 | return 1; |
| 1011 | } |
| 1012 | |
| 1013 | if (unlikely(produced - consumed >= n_subbufs)) { |
Masami Hiramatsu | a66e356 | 2007-06-27 14:10:04 -0700 | [diff] [blame] | 1014 | consumed = produced - n_subbufs + 1; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1015 | buf->subbufs_consumed = consumed; |
Masami Hiramatsu | a66e356 | 2007-06-27 14:10:04 -0700 | [diff] [blame] | 1016 | buf->bytes_consumed = 0; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1017 | } |
Daniel Walker | 1bfbc60 | 2007-10-18 03:06:05 -0700 | [diff] [blame] | 1018 | |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1019 | produced = (produced % n_subbufs) * subbuf_size + buf->offset; |
| 1020 | consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed; |
| 1021 | |
| 1022 | if (consumed > produced) |
| 1023 | produced += n_subbufs * subbuf_size; |
Daniel Walker | 1bfbc60 | 2007-10-18 03:06:05 -0700 | [diff] [blame] | 1024 | |
Tom Zanussi | 3219445 | 2008-08-05 13:01:10 -0700 | [diff] [blame] | 1025 | if (consumed == produced) { |
| 1026 | if (buf->offset == subbuf_size && |
| 1027 | buf->subbufs_produced > buf->subbufs_consumed) |
| 1028 | return 1; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1029 | return 0; |
Tom Zanussi | 3219445 | 2008-08-05 13:01:10 -0700 | [diff] [blame] | 1030 | } |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1031 | |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1032 | return 1; |
| 1033 | } |
| 1034 | |
| 1035 | /** |
| 1036 | * relay_file_read_subbuf_avail - return bytes available in sub-buffer |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 1037 | * @read_pos: file read position |
| 1038 | * @buf: relay channel buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1039 | */ |
| 1040 | static size_t relay_file_read_subbuf_avail(size_t read_pos, |
| 1041 | struct rchan_buf *buf) |
| 1042 | { |
| 1043 | size_t padding, avail = 0; |
| 1044 | size_t read_subbuf, read_offset, write_subbuf, write_offset; |
| 1045 | size_t subbuf_size = buf->chan->subbuf_size; |
| 1046 | |
| 1047 | write_subbuf = (buf->data - buf->start) / subbuf_size; |
| 1048 | write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset; |
| 1049 | read_subbuf = read_pos / subbuf_size; |
| 1050 | read_offset = read_pos % subbuf_size; |
| 1051 | padding = buf->padding[read_subbuf]; |
| 1052 | |
| 1053 | if (read_subbuf == write_subbuf) { |
| 1054 | if (read_offset + padding < write_offset) |
| 1055 | avail = write_offset - (read_offset + padding); |
| 1056 | } else |
| 1057 | avail = (subbuf_size - padding) - read_offset; |
| 1058 | |
| 1059 | return avail; |
| 1060 | } |
| 1061 | |
| 1062 | /** |
| 1063 | * relay_file_read_start_pos - find the first available byte to read |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 1064 | * @read_pos: file read position |
| 1065 | * @buf: relay channel buffer |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1066 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 1067 | * If the @read_pos is in the middle of padding, return the |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1068 | * position of the first actually available byte, otherwise |
| 1069 | * return the original value. |
| 1070 | */ |
| 1071 | static size_t relay_file_read_start_pos(size_t read_pos, |
| 1072 | struct rchan_buf *buf) |
| 1073 | { |
| 1074 | size_t read_subbuf, padding, padding_start, padding_end; |
| 1075 | size_t subbuf_size = buf->chan->subbuf_size; |
| 1076 | size_t n_subbufs = buf->chan->n_subbufs; |
David Wilder | 8d62fde | 2007-06-27 14:10:03 -0700 | [diff] [blame] | 1077 | size_t consumed = buf->subbufs_consumed % n_subbufs; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1078 | |
David Wilder | 8d62fde | 2007-06-27 14:10:03 -0700 | [diff] [blame] | 1079 | if (!read_pos) |
| 1080 | read_pos = consumed * subbuf_size + buf->bytes_consumed; |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1081 | read_subbuf = read_pos / subbuf_size; |
| 1082 | padding = buf->padding[read_subbuf]; |
| 1083 | padding_start = (read_subbuf + 1) * subbuf_size - padding; |
| 1084 | padding_end = (read_subbuf + 1) * subbuf_size; |
| 1085 | if (read_pos >= padding_start && read_pos < padding_end) { |
| 1086 | read_subbuf = (read_subbuf + 1) % n_subbufs; |
| 1087 | read_pos = read_subbuf * subbuf_size; |
| 1088 | } |
| 1089 | |
| 1090 | return read_pos; |
| 1091 | } |
| 1092 | |
| 1093 | /** |
| 1094 | * relay_file_read_end_pos - return the new read position |
Randy Dunlap | 4c78a66 | 2006-09-29 01:59:10 -0700 | [diff] [blame] | 1095 | * @read_pos: file read position |
| 1096 | * @buf: relay channel buffer |
| 1097 | * @count: number of bytes to be read |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1098 | */ |
| 1099 | static size_t relay_file_read_end_pos(struct rchan_buf *buf, |
| 1100 | size_t read_pos, |
| 1101 | size_t count) |
| 1102 | { |
| 1103 | size_t read_subbuf, padding, end_pos; |
| 1104 | size_t subbuf_size = buf->chan->subbuf_size; |
| 1105 | size_t n_subbufs = buf->chan->n_subbufs; |
| 1106 | |
| 1107 | read_subbuf = read_pos / subbuf_size; |
| 1108 | padding = buf->padding[read_subbuf]; |
| 1109 | if (read_pos % subbuf_size + count + padding == subbuf_size) |
| 1110 | end_pos = (read_subbuf + 1) * subbuf_size; |
| 1111 | else |
| 1112 | end_pos = read_pos + count; |
| 1113 | if (end_pos >= subbuf_size * n_subbufs) |
| 1114 | end_pos = 0; |
| 1115 | |
| 1116 | return end_pos; |
| 1117 | } |
| 1118 | |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1119 | static ssize_t relay_file_read(struct file *filp, |
| 1120 | char __user *buffer, |
| 1121 | size_t count, |
| 1122 | loff_t *ppos) |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1123 | { |
| 1124 | struct rchan_buf *buf = filp->private_data; |
| 1125 | size_t read_start, avail; |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1126 | size_t written = 0; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1127 | int ret; |
| 1128 | |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1129 | if (!count) |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1130 | return 0; |
| 1131 | |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 1132 | inode_lock(file_inode(filp)); |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1133 | do { |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1134 | void *from; |
| 1135 | |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1136 | if (!relay_file_read_avail(buf, *ppos)) |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1137 | break; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1138 | |
| 1139 | read_start = relay_file_read_start_pos(*ppos, buf); |
| 1140 | avail = relay_file_read_subbuf_avail(read_start, buf); |
| 1141 | if (!avail) |
| 1142 | break; |
| 1143 | |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1144 | avail = min(count, avail); |
| 1145 | from = buf->start + read_start; |
| 1146 | ret = avail; |
| 1147 | if (copy_to_user(buffer, from, avail)) |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1148 | break; |
| 1149 | |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1150 | buffer += ret; |
| 1151 | written += ret; |
| 1152 | count -= ret; |
| 1153 | |
| 1154 | relay_file_read_consume(buf, read_start, ret); |
| 1155 | *ppos = relay_file_read_end_pos(buf, read_start, ret); |
| 1156 | } while (count); |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 1157 | inode_unlock(file_inode(filp)); |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1158 | |
Al Viro | a7c2242 | 2016-09-25 22:52:02 -0400 | [diff] [blame] | 1159 | return written; |
Tom Zanussi | 6dac40a | 2006-03-23 19:58:45 +0100 | [diff] [blame] | 1160 | } |
| 1161 | |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1162 | static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed) |
| 1163 | { |
| 1164 | rbuf->bytes_consumed += bytes_consumed; |
| 1165 | |
| 1166 | if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) { |
| 1167 | relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1); |
| 1168 | rbuf->bytes_consumed %= rbuf->chan->subbuf_size; |
| 1169 | } |
| 1170 | } |
| 1171 | |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1172 | static void relay_pipe_buf_release(struct pipe_inode_info *pipe, |
| 1173 | struct pipe_buffer *buf) |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1174 | { |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1175 | struct rchan_buf *rbuf; |
| 1176 | |
| 1177 | rbuf = (struct rchan_buf *)page_private(buf->page); |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1178 | relay_consume_bytes(rbuf, buf->private); |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1179 | } |
| 1180 | |
Alexey Dobriyan | 28dfef8 | 2009-12-15 16:46:48 -0800 | [diff] [blame] | 1181 | static const struct pipe_buf_operations relay_pipe_buf_ops = { |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1182 | .can_merge = 0, |
Jens Axboe | cac36bb0 | 2007-06-14 13:10:48 +0200 | [diff] [blame] | 1183 | .confirm = generic_pipe_buf_confirm, |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1184 | .release = relay_pipe_buf_release, |
| 1185 | .steal = generic_pipe_buf_steal, |
| 1186 | .get = generic_pipe_buf_get, |
| 1187 | }; |
| 1188 | |
Jens Axboe | 5eb7f9f | 2008-03-26 12:04:09 +0100 | [diff] [blame] | 1189 | static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i) |
| 1190 | { |
| 1191 | } |
| 1192 | |
Tom Zanussi | d3f35d9 | 2007-07-12 08:12:05 +0200 | [diff] [blame] | 1193 | /* |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1194 | * subbuf_splice_actor - splice up to one subbuf's worth of data |
| 1195 | */ |
Dan Carpenter | 5f1664f | 2010-03-05 13:42:51 -0800 | [diff] [blame] | 1196 | static ssize_t subbuf_splice_actor(struct file *in, |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1197 | loff_t *ppos, |
| 1198 | struct pipe_inode_info *pipe, |
| 1199 | size_t len, |
| 1200 | unsigned int flags, |
| 1201 | int *nonpad_ret) |
| 1202 | { |
Dan Carpenter | 5f1664f | 2010-03-05 13:42:51 -0800 | [diff] [blame] | 1203 | unsigned int pidx, poff, total_len, subbuf_pages, nr_pages; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1204 | struct rchan_buf *rbuf = in->private_data; |
| 1205 | unsigned int subbuf_size = rbuf->chan->subbuf_size; |
Tom Zanussi | 24da24d | 2007-07-12 08:12:04 +0200 | [diff] [blame] | 1206 | uint64_t pos = (uint64_t) *ppos; |
| 1207 | uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size; |
| 1208 | size_t read_start = (size_t) do_div(pos, alloc_size); |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1209 | size_t read_subbuf = read_start / subbuf_size; |
| 1210 | size_t padding = rbuf->padding[read_subbuf]; |
| 1211 | size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1212 | struct page *pages[PIPE_DEF_BUFFERS]; |
| 1213 | struct partial_page partial[PIPE_DEF_BUFFERS]; |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1214 | struct splice_pipe_desc spd = { |
| 1215 | .pages = pages, |
| 1216 | .nr_pages = 0, |
Eric Dumazet | 047fe36 | 2012-06-12 15:24:40 +0200 | [diff] [blame] | 1217 | .nr_pages_max = PIPE_DEF_BUFFERS, |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1218 | .partial = partial, |
| 1219 | .flags = flags, |
| 1220 | .ops = &relay_pipe_buf_ops, |
Jens Axboe | 5eb7f9f | 2008-03-26 12:04:09 +0100 | [diff] [blame] | 1221 | .spd_release = relay_page_release, |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1222 | }; |
Dan Carpenter | 5f1664f | 2010-03-05 13:42:51 -0800 | [diff] [blame] | 1223 | ssize_t ret; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1224 | |
| 1225 | if (rbuf->subbufs_produced == rbuf->subbufs_consumed) |
| 1226 | return 0; |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1227 | if (splice_grow_spd(pipe, &spd)) |
| 1228 | return -ENOMEM; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1229 | |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1230 | /* |
| 1231 | * Adjust read len, if longer than what is available |
| 1232 | */ |
| 1233 | if (len > (subbuf_size - read_start % subbuf_size)) |
| 1234 | len = subbuf_size - read_start % subbuf_size; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1235 | |
| 1236 | subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT; |
| 1237 | pidx = (read_start / PAGE_SIZE) % subbuf_pages; |
| 1238 | poff = read_start & ~PAGE_MASK; |
Al Viro | a786c06 | 2014-04-11 12:01:03 -0400 | [diff] [blame] | 1239 | nr_pages = min_t(unsigned int, subbuf_pages, spd.nr_pages_max); |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1240 | |
Jens Axboe | 16d5466 | 2008-03-17 09:04:59 +0100 | [diff] [blame] | 1241 | for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) { |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1242 | unsigned int this_len, this_end, private; |
| 1243 | unsigned int cur_pos = read_start + total_len; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1244 | |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1245 | if (!len) |
| 1246 | break; |
| 1247 | |
| 1248 | this_len = min_t(unsigned long, len, PAGE_SIZE - poff); |
| 1249 | private = this_len; |
| 1250 | |
| 1251 | spd.pages[spd.nr_pages] = rbuf->page_array[pidx]; |
| 1252 | spd.partial[spd.nr_pages].offset = poff; |
| 1253 | |
| 1254 | this_end = cur_pos + this_len; |
| 1255 | if (this_end >= nonpad_end) { |
| 1256 | this_len = nonpad_end - cur_pos; |
| 1257 | private = this_len + padding; |
| 1258 | } |
| 1259 | spd.partial[spd.nr_pages].len = this_len; |
| 1260 | spd.partial[spd.nr_pages].private = private; |
| 1261 | |
| 1262 | len -= this_len; |
| 1263 | total_len += this_len; |
| 1264 | poff = 0; |
| 1265 | pidx = (pidx + 1) % subbuf_pages; |
| 1266 | |
| 1267 | if (this_end >= nonpad_end) { |
| 1268 | spd.nr_pages++; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1269 | break; |
| 1270 | } |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1271 | } |
| 1272 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1273 | ret = 0; |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1274 | if (!spd.nr_pages) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1275 | goto out; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1276 | |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1277 | ret = *nonpad_ret = splice_to_pipe(pipe, &spd); |
| 1278 | if (ret < 0 || ret < total_len) |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1279 | goto out; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1280 | |
Jens Axboe | 1db60cf | 2007-06-12 08:43:46 +0200 | [diff] [blame] | 1281 | if (read_start + ret == nonpad_end) |
| 1282 | ret += padding; |
| 1283 | |
Jens Axboe | 35f3d14 | 2010-05-20 10:43:18 +0200 | [diff] [blame] | 1284 | out: |
Eric Dumazet | 047fe36 | 2012-06-12 15:24:40 +0200 | [diff] [blame] | 1285 | splice_shrink_spd(&spd); |
| 1286 | return ret; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1287 | } |
| 1288 | |
| 1289 | static ssize_t relay_file_splice_read(struct file *in, |
| 1290 | loff_t *ppos, |
| 1291 | struct pipe_inode_info *pipe, |
| 1292 | size_t len, |
| 1293 | unsigned int flags) |
| 1294 | { |
| 1295 | ssize_t spliced; |
| 1296 | int ret; |
| 1297 | int nonpad_ret = 0; |
| 1298 | |
| 1299 | ret = 0; |
| 1300 | spliced = 0; |
| 1301 | |
Tom Zanussi | a82c53a | 2008-05-09 13:28:36 +0200 | [diff] [blame] | 1302 | while (len && !spliced) { |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1303 | ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret); |
| 1304 | if (ret < 0) |
| 1305 | break; |
| 1306 | else if (!ret) { |
Tom Zanussi | fbb5b7a | 2008-12-09 13:14:10 -0800 | [diff] [blame] | 1307 | if (flags & SPLICE_F_NONBLOCK) |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1308 | ret = -EAGAIN; |
Tom Zanussi | fbb5b7a | 2008-12-09 13:14:10 -0800 | [diff] [blame] | 1309 | break; |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1310 | } |
| 1311 | |
| 1312 | *ppos += ret; |
| 1313 | if (ret > len) |
| 1314 | len = 0; |
| 1315 | else |
| 1316 | len -= ret; |
| 1317 | spliced += nonpad_ret; |
| 1318 | nonpad_ret = 0; |
| 1319 | } |
| 1320 | |
| 1321 | if (spliced) |
| 1322 | return spliced; |
| 1323 | |
| 1324 | return ret; |
Jens Axboe | 221415d | 2006-03-23 19:57:55 +0100 | [diff] [blame] | 1325 | } |
| 1326 | |
Helge Deller | 15ad7cd | 2006-12-06 20:40:36 -0800 | [diff] [blame] | 1327 | const struct file_operations relay_file_operations = { |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1328 | .open = relay_file_open, |
| 1329 | .poll = relay_file_poll, |
| 1330 | .mmap = relay_file_mmap, |
| 1331 | .read = relay_file_read, |
| 1332 | .llseek = no_llseek, |
| 1333 | .release = relay_file_release, |
Tom Zanussi | ebf9909 | 2007-06-04 09:12:05 +0200 | [diff] [blame] | 1334 | .splice_read = relay_file_splice_read, |
Jens Axboe | b86ff981 | 2006-03-23 19:56:55 +0100 | [diff] [blame] | 1335 | }; |
| 1336 | EXPORT_SYMBOL_GPL(relay_file_operations); |