Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Tty buffer allocation management |
| 3 | */ |
| 4 | |
| 5 | #include <linux/types.h> |
| 6 | #include <linux/errno.h> |
| 7 | #include <linux/tty.h> |
| 8 | #include <linux/tty_driver.h> |
| 9 | #include <linux/tty_flip.h> |
| 10 | #include <linux/timer.h> |
| 11 | #include <linux/string.h> |
| 12 | #include <linux/slab.h> |
| 13 | #include <linux/sched.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/wait.h> |
| 16 | #include <linux/bitops.h> |
| 17 | #include <linux/delay.h> |
| 18 | #include <linux/module.h> |
George Spelvin | 593fb1ae4 | 2013-02-12 02:00:43 -0500 | [diff] [blame] | 19 | #include <linux/ratelimit.h> |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 20 | |
Peter Hurley | 1cef50e | 2013-06-15 09:36:02 -0400 | [diff] [blame] | 21 | |
| 22 | #define MIN_TTYB_SIZE 256 |
| 23 | #define TTYB_ALIGN_MASK 255 |
| 24 | |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 25 | /* |
| 26 | * Byte threshold to limit memory consumption for flip buffers. |
| 27 | * The actual memory limit is > 2x this amount. |
| 28 | */ |
Peter Hurley | 4d18e6ef | 2013-11-22 12:09:55 -0500 | [diff] [blame] | 29 | #define TTYB_DEFAULT_MEM_LIMIT 65536 |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 30 | |
Peter Hurley | 9114fe8 | 2013-06-15 09:36:16 -0400 | [diff] [blame] | 31 | /* |
| 32 | * We default to dicing tty buffer allocations to this many characters |
| 33 | * in order to avoid multiple page allocations. We know the size of |
| 34 | * tty_buffer itself but it must also be taken into account that the |
| 35 | * the buffer is 256 byte aligned. See tty_buffer_find for the allocation |
| 36 | * logic this must match |
| 37 | */ |
| 38 | |
| 39 | #define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF) |
| 40 | |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 41 | |
| 42 | /** |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 43 | * tty_buffer_lock_exclusive - gain exclusive access to buffer |
| 44 | * tty_buffer_unlock_exclusive - release exclusive access |
| 45 | * |
| 46 | * @port - tty_port owning the flip buffer |
| 47 | * |
| 48 | * Guarantees safe use of the line discipline's receive_buf() method by |
| 49 | * excluding the buffer work and any pending flush from using the flip |
| 50 | * buffer. Data can continue to be added concurrently to the flip buffer |
| 51 | * from the driver side. |
| 52 | * |
| 53 | * On release, the buffer work is restarted if there is data in the |
| 54 | * flip buffer |
| 55 | */ |
| 56 | |
| 57 | void tty_buffer_lock_exclusive(struct tty_port *port) |
| 58 | { |
| 59 | struct tty_bufhead *buf = &port->buf; |
| 60 | |
| 61 | atomic_inc(&buf->priority); |
| 62 | mutex_lock(&buf->lock); |
| 63 | } |
| 64 | |
| 65 | void tty_buffer_unlock_exclusive(struct tty_port *port) |
| 66 | { |
| 67 | struct tty_bufhead *buf = &port->buf; |
| 68 | int restart; |
| 69 | |
| 70 | restart = buf->head->commit != buf->head->read; |
| 71 | |
| 72 | atomic_dec(&buf->priority); |
| 73 | mutex_unlock(&buf->lock); |
| 74 | if (restart) |
| 75 | queue_work(system_unbound_wq, &buf->work); |
| 76 | } |
| 77 | |
| 78 | /** |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 79 | * tty_buffer_space_avail - return unused buffer space |
| 80 | * @port - tty_port owning the flip buffer |
| 81 | * |
| 82 | * Returns the # of bytes which can be written by the driver without |
| 83 | * reaching the buffer limit. |
| 84 | * |
| 85 | * Note: this does not guarantee that memory is available to write |
| 86 | * the returned # of bytes (use tty_prepare_flip_string_xxx() to |
| 87 | * pre-allocate if memory guarantee is required). |
| 88 | */ |
| 89 | |
| 90 | int tty_buffer_space_avail(struct tty_port *port) |
| 91 | { |
Peter Hurley | 5dda4ca | 2013-11-22 12:09:56 -0500 | [diff] [blame] | 92 | int space = port->buf.mem_limit - atomic_read(&port->buf.mem_used); |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 93 | return max(space, 0); |
| 94 | } |
Peter Hurley | c4a8dab | 2013-11-22 13:06:08 -0500 | [diff] [blame] | 95 | EXPORT_SYMBOL_GPL(tty_buffer_space_avail); |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 96 | |
Peter Hurley | 9dd5139 | 2013-06-15 09:36:03 -0400 | [diff] [blame] | 97 | static void tty_buffer_reset(struct tty_buffer *p, size_t size) |
| 98 | { |
| 99 | p->used = 0; |
| 100 | p->size = size; |
| 101 | p->next = NULL; |
| 102 | p->commit = 0; |
| 103 | p->read = 0; |
| 104 | } |
| 105 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 106 | /** |
| 107 | * tty_buffer_free_all - free buffers used by a tty |
| 108 | * @tty: tty to free from |
| 109 | * |
| 110 | * Remove all the buffers pending on a tty whether queued with data |
| 111 | * or in the free ring. Must be called when the tty is no longer in use |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 112 | */ |
| 113 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 114 | void tty_buffer_free_all(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 115 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 116 | struct tty_bufhead *buf = &port->buf; |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 117 | struct tty_buffer *p, *next; |
| 118 | struct llist_node *llist; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 119 | |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 120 | while ((p = buf->head) != NULL) { |
| 121 | buf->head = p->next; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 122 | if (p->size > 0) |
| 123 | kfree(p); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 124 | } |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 125 | llist = llist_del_all(&buf->free); |
| 126 | llist_for_each_entry_safe(p, next, llist, free) |
Peter Hurley | 2cf7b67 | 2013-06-15 09:36:05 -0400 | [diff] [blame] | 127 | kfree(p); |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 128 | |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 129 | tty_buffer_reset(&buf->sentinel, 0); |
| 130 | buf->head = &buf->sentinel; |
| 131 | buf->tail = &buf->sentinel; |
Peter Hurley | 7bfe0b7 | 2013-06-15 09:36:08 -0400 | [diff] [blame] | 132 | |
Peter Hurley | 5dda4ca | 2013-11-22 12:09:56 -0500 | [diff] [blame] | 133 | atomic_set(&buf->mem_used, 0); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 134 | } |
| 135 | |
| 136 | /** |
| 137 | * tty_buffer_alloc - allocate a tty buffer |
| 138 | * @tty: tty device |
| 139 | * @size: desired size (characters) |
| 140 | * |
| 141 | * Allocate a new tty buffer to hold the desired number of characters. |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 142 | * We round our buffers off in 256 character chunks to get better |
| 143 | * allocation behaviour. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 144 | * Return NULL if out of memory or the allocation would exceed the |
| 145 | * per device queue |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 146 | */ |
| 147 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 148 | static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 149 | { |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 150 | struct llist_node *free; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 151 | struct tty_buffer *p; |
| 152 | |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 153 | /* Round the buffer size out */ |
| 154 | size = __ALIGN_MASK(size, TTYB_ALIGN_MASK); |
| 155 | |
| 156 | if (size <= MIN_TTYB_SIZE) { |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 157 | free = llist_del_first(&port->buf.free); |
| 158 | if (free) { |
| 159 | p = llist_entry(free, struct tty_buffer, free); |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 160 | goto found; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | /* Should possibly check if this fails for the largest buffer we |
| 165 | have queued and recycle that ? */ |
Peter Hurley | 5dda4ca | 2013-11-22 12:09:56 -0500 | [diff] [blame] | 166 | if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 167 | return NULL; |
| 168 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); |
| 169 | if (p == NULL) |
| 170 | return NULL; |
Peter Hurley | 9dd5139 | 2013-06-15 09:36:03 -0400 | [diff] [blame] | 171 | |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 172 | found: |
Peter Hurley | 9dd5139 | 2013-06-15 09:36:03 -0400 | [diff] [blame] | 173 | tty_buffer_reset(p, size); |
Peter Hurley | 5dda4ca | 2013-11-22 12:09:56 -0500 | [diff] [blame] | 174 | atomic_add(size, &port->buf.mem_used); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 175 | return p; |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * tty_buffer_free - free a tty buffer |
| 180 | * @tty: tty owning the buffer |
| 181 | * @b: the buffer to free |
| 182 | * |
| 183 | * Free a tty buffer, or add it to the free list according to our |
| 184 | * internal strategy |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 185 | */ |
| 186 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 187 | static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 188 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 189 | struct tty_bufhead *buf = &port->buf; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 190 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 191 | /* Dumb strategy for now - should keep some stats */ |
Peter Hurley | 5dda4ca | 2013-11-22 12:09:56 -0500 | [diff] [blame] | 192 | WARN_ON(atomic_sub_return(b->size, &buf->mem_used) < 0); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 193 | |
Peter Hurley | 1cef50e | 2013-06-15 09:36:02 -0400 | [diff] [blame] | 194 | if (b->size > MIN_TTYB_SIZE) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 195 | kfree(b); |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 196 | else if (b->size > 0) |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 197 | llist_add(&b->free, &buf->free); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 198 | } |
| 199 | |
| 200 | /** |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 201 | * tty_buffer_flush - flush full tty buffers |
| 202 | * @tty: tty to flush |
| 203 | * |
Peter Hurley | 753023d | 2013-12-02 16:12:02 -0500 | [diff] [blame] | 204 | * flush all the buffers containing receive data. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 205 | * |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 206 | * Locking: takes buffer lock to ensure single-threaded flip buffer |
Peter Hurley | e9975fd | 2013-06-15 09:36:10 -0400 | [diff] [blame] | 207 | * 'consumer' |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 208 | */ |
| 209 | |
| 210 | void tty_buffer_flush(struct tty_struct *tty) |
| 211 | { |
Jiri Slaby | 2fc2066 | 2012-10-18 22:26:44 +0200 | [diff] [blame] | 212 | struct tty_port *port = tty->port; |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 213 | struct tty_bufhead *buf = &port->buf; |
Peter Hurley | 47aa658 | 2013-06-15 09:36:14 -0400 | [diff] [blame] | 214 | struct tty_buffer *next; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 215 | |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 216 | atomic_inc(&buf->priority); |
Peter Hurley | e9975fd | 2013-06-15 09:36:10 -0400 | [diff] [blame] | 217 | |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 218 | mutex_lock(&buf->lock); |
Peter Hurley | 47aa658 | 2013-06-15 09:36:14 -0400 | [diff] [blame] | 219 | while ((next = buf->head->next) != NULL) { |
| 220 | tty_buffer_free(port, buf->head); |
| 221 | buf->head = next; |
| 222 | } |
| 223 | buf->head->read = buf->head->commit; |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 224 | atomic_dec(&buf->priority); |
| 225 | mutex_unlock(&buf->lock); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 226 | } |
| 227 | |
| 228 | /** |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 229 | * tty_buffer_request_room - grow tty buffer if needed |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 230 | * @tty: tty structure |
| 231 | * @size: size desired |
| 232 | * |
| 233 | * Make at least size bytes of linear space available for the tty |
| 234 | * buffer. If we fail return the size we managed to find. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 235 | */ |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 236 | int tty_buffer_request_room(struct tty_port *port, size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 237 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 238 | struct tty_bufhead *buf = &port->buf; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 239 | struct tty_buffer *b, *n; |
| 240 | int left; |
Peter Hurley | e8437d7 | 2013-06-15 09:36:09 -0400 | [diff] [blame] | 241 | |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 242 | b = buf->tail; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 243 | left = b->size - b->used; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 244 | |
| 245 | if (left < size) { |
| 246 | /* This is the slow path - looking for new buffers to use */ |
Peter Hurley | 11b9faa | 2013-06-15 09:36:04 -0400 | [diff] [blame] | 247 | if ((n = tty_buffer_alloc(port, size)) != NULL) { |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 248 | buf->tail = n; |
Peter Hurley | e8437d7 | 2013-06-15 09:36:09 -0400 | [diff] [blame] | 249 | b->commit = b->used; |
| 250 | smp_mb(); |
| 251 | b->next = n; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 252 | } else |
| 253 | size = left; |
| 254 | } |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 255 | return size; |
| 256 | } |
| 257 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
| 258 | |
| 259 | /** |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 260 | * tty_insert_flip_string_fixed_flag - Add characters to the tty buffer |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 261 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 262 | * @chars: characters |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 263 | * @flag: flag value for each character |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 264 | * @size: size |
| 265 | * |
| 266 | * Queue a series of bytes to the tty buffering. All the characters |
Johan Hovold | ccc5ca8 | 2010-05-07 19:58:32 +0200 | [diff] [blame] | 267 | * passed are marked with the supplied flag. Returns the number added. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 268 | */ |
| 269 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 270 | int tty_insert_flip_string_fixed_flag(struct tty_port *port, |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 271 | const unsigned char *chars, char flag, size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 272 | { |
| 273 | int copied = 0; |
| 274 | do { |
Fang Wenqi | d4bee0a | 2010-03-09 18:54:28 +0800 | [diff] [blame] | 275 | int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 276 | int space = tty_buffer_request_room(port, goal); |
| 277 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 278 | if (unlikely(space == 0)) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 279 | break; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 280 | memcpy(char_buf_ptr(tb, tb->used), chars, space); |
| 281 | memset(flag_buf_ptr(tb, tb->used), flag, space); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 282 | tb->used += space; |
| 283 | copied += space; |
| 284 | chars += space; |
| 285 | /* There is a small chance that we need to split the data over |
| 286 | several buffers. If this is the case we must loop */ |
| 287 | } while (unlikely(size > copied)); |
| 288 | return copied; |
| 289 | } |
Alan Cox | 2832fc1 | 2010-02-18 16:43:54 +0000 | [diff] [blame] | 290 | EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 291 | |
| 292 | /** |
| 293 | * tty_insert_flip_string_flags - Add characters to the tty buffer |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 294 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 295 | * @chars: characters |
| 296 | * @flags: flag bytes |
| 297 | * @size: size |
| 298 | * |
| 299 | * Queue a series of bytes to the tty buffering. For each character |
| 300 | * the flags array indicates the status of the character. Returns the |
| 301 | * number added. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 302 | */ |
| 303 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 304 | int tty_insert_flip_string_flags(struct tty_port *port, |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 305 | const unsigned char *chars, const char *flags, size_t size) |
| 306 | { |
| 307 | int copied = 0; |
| 308 | do { |
Fang Wenqi | d4bee0a | 2010-03-09 18:54:28 +0800 | [diff] [blame] | 309 | int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 310 | int space = tty_buffer_request_room(port, goal); |
| 311 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 312 | if (unlikely(space == 0)) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 313 | break; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 314 | memcpy(char_buf_ptr(tb, tb->used), chars, space); |
| 315 | memcpy(flag_buf_ptr(tb, tb->used), flags, space); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 316 | tb->used += space; |
| 317 | copied += space; |
| 318 | chars += space; |
| 319 | flags += space; |
| 320 | /* There is a small chance that we need to split the data over |
| 321 | several buffers. If this is the case we must loop */ |
| 322 | } while (unlikely(size > copied)); |
| 323 | return copied; |
| 324 | } |
| 325 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
| 326 | |
| 327 | /** |
| 328 | * tty_schedule_flip - push characters to ldisc |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 329 | * @port: tty port to push from |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 330 | * |
| 331 | * Takes any pending buffers and transfers their ownership to the |
| 332 | * ldisc side of the queue. It then schedules those characters for |
| 333 | * processing by the line discipline. |
Ivo Sieben | cee4ad1 | 2012-09-27 14:02:05 +0200 | [diff] [blame] | 334 | * Note that this function can only be used when the low_latency flag |
| 335 | * is unset. Otherwise the workqueue won't be flushed. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 336 | */ |
| 337 | |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 338 | void tty_schedule_flip(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 339 | { |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 340 | struct tty_bufhead *buf = &port->buf; |
Jiri Slaby | 6732c8b | 2013-01-03 15:53:07 +0100 | [diff] [blame] | 341 | WARN_ON(port->low_latency); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 342 | |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 343 | buf->tail->commit = buf->tail->used; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 344 | schedule_work(&buf->work); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 345 | } |
| 346 | EXPORT_SYMBOL(tty_schedule_flip); |
| 347 | |
| 348 | /** |
| 349 | * tty_prepare_flip_string - make room for characters |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 350 | * @port: tty port |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 351 | * @chars: return pointer for character write area |
| 352 | * @size: desired size |
| 353 | * |
| 354 | * Prepare a block of space in the buffer for data. Returns the length |
| 355 | * available and buffer pointer to the space which is now allocated and |
| 356 | * accounted for as ready for normal characters. This is used for drivers |
| 357 | * that need their own block copy routines into the buffer. There is no |
| 358 | * guarantee the buffer is a DMA target! |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 359 | */ |
| 360 | |
Jiri Slaby | 2f69335 | 2013-01-03 15:53:02 +0100 | [diff] [blame] | 361 | int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 362 | size_t size) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 363 | { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 364 | int space = tty_buffer_request_room(port, size); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 365 | if (likely(space)) { |
Ilya Zykov | 64325a3 | 2013-01-19 18:16:20 +0400 | [diff] [blame] | 366 | struct tty_buffer *tb = port->buf.tail; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 367 | *chars = char_buf_ptr(tb, tb->used); |
| 368 | memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 369 | tb->used += space; |
| 370 | } |
| 371 | return space; |
| 372 | } |
| 373 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); |
| 374 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 375 | |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 376 | static int |
| 377 | receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count) |
| 378 | { |
| 379 | struct tty_ldisc *disc = tty->ldisc; |
Peter Hurley | 1fc359f | 2013-06-15 09:36:01 -0400 | [diff] [blame] | 380 | unsigned char *p = char_buf_ptr(head, head->read); |
| 381 | char *f = flag_buf_ptr(head, head->read); |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 382 | |
Peter Hurley | 24a89d1 | 2013-06-15 09:14:15 -0400 | [diff] [blame] | 383 | if (disc->ops->receive_buf2) |
| 384 | count = disc->ops->receive_buf2(tty, p, f, count); |
| 385 | else { |
| 386 | count = min_t(int, count, tty->receive_room); |
| 387 | if (count) |
| 388 | disc->ops->receive_buf(tty, p, f, count); |
| 389 | } |
Peter Hurley | da261e7 | 2013-06-15 09:14:14 -0400 | [diff] [blame] | 390 | head->read += count; |
| 391 | return count; |
| 392 | } |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 393 | |
| 394 | /** |
| 395 | * flush_to_ldisc |
| 396 | * @work: tty structure passed from work queue. |
| 397 | * |
| 398 | * This routine is called out of the software interrupt to flush data |
| 399 | * from the buffer chain to the line discipline. |
| 400 | * |
Peter Hurley | e9975fd | 2013-06-15 09:36:10 -0400 | [diff] [blame] | 401 | * The receive_buf method is single threaded for each tty instance. |
| 402 | * |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 403 | * Locking: takes buffer lock to ensure single-threaded flip buffer |
Peter Hurley | e9975fd | 2013-06-15 09:36:10 -0400 | [diff] [blame] | 404 | * 'consumer' |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 405 | */ |
| 406 | |
| 407 | static void flush_to_ldisc(struct work_struct *work) |
| 408 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 409 | struct tty_port *port = container_of(work, struct tty_port, buf.work); |
| 410 | struct tty_bufhead *buf = &port->buf; |
| 411 | struct tty_struct *tty; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 412 | struct tty_ldisc *disc; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 413 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 414 | tty = port->itty; |
Jiri Slaby | 34dcfb8 | 2013-02-27 22:30:24 +0100 | [diff] [blame] | 415 | if (tty == NULL) |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 416 | return; |
| 417 | |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 418 | disc = tty_ldisc_ref(tty); |
Peter Hurley | 3669752 | 2013-06-15 07:04:48 -0400 | [diff] [blame] | 419 | if (disc == NULL) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 420 | return; |
| 421 | |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 422 | mutex_lock(&buf->lock); |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 423 | |
Peter Hurley | d7a68be | 2013-06-15 09:36:11 -0400 | [diff] [blame] | 424 | while (1) { |
| 425 | struct tty_buffer *head = buf->head; |
| 426 | int count; |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 427 | |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 428 | /* Ldisc or user is trying to gain exclusive access */ |
| 429 | if (atomic_read(&buf->priority)) |
Peter Hurley | d7a68be | 2013-06-15 09:36:11 -0400 | [diff] [blame] | 430 | break; |
Peter Hurley | e9975fd | 2013-06-15 09:36:10 -0400 | [diff] [blame] | 431 | |
Peter Hurley | d7a68be | 2013-06-15 09:36:11 -0400 | [diff] [blame] | 432 | count = head->commit - head->read; |
| 433 | if (!count) { |
| 434 | if (head->next == NULL) |
Peter Hurley | 39f610e | 2013-03-20 13:20:43 -0400 | [diff] [blame] | 435 | break; |
Peter Hurley | d7a68be | 2013-06-15 09:36:11 -0400 | [diff] [blame] | 436 | buf->head = head->next; |
| 437 | tty_buffer_free(port, head); |
| 438 | continue; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 439 | } |
Peter Hurley | d7a68be | 2013-06-15 09:36:11 -0400 | [diff] [blame] | 440 | |
| 441 | count = receive_buf(tty, head, count); |
| 442 | if (!count) |
| 443 | break; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 444 | } |
Linus Torvalds | 4524200 | 2009-10-14 08:59:49 -0700 | [diff] [blame] | 445 | |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 446 | mutex_unlock(&buf->lock); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 447 | |
| 448 | tty_ldisc_deref(disc); |
| 449 | } |
| 450 | |
| 451 | /** |
OGAWA Hirofumi | e043e42 | 2009-07-29 12:15:56 -0700 | [diff] [blame] | 452 | * tty_flush_to_ldisc |
| 453 | * @tty: tty to push |
| 454 | * |
| 455 | * Push the terminal flip buffers to the line discipline. |
| 456 | * |
| 457 | * Must not be called from IRQ context. |
| 458 | */ |
| 459 | void tty_flush_to_ldisc(struct tty_struct *tty) |
| 460 | { |
Jiri Slaby | d6c53c0 | 2013-01-03 15:53:05 +0100 | [diff] [blame] | 461 | if (!tty->port->low_latency) |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 462 | flush_work(&tty->port->buf.work); |
OGAWA Hirofumi | e043e42 | 2009-07-29 12:15:56 -0700 | [diff] [blame] | 463 | } |
| 464 | |
| 465 | /** |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 466 | * tty_flip_buffer_push - terminal |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 467 | * @port: tty port to push |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 468 | * |
| 469 | * Queue a push of the terminal flip buffers to the line discipline. This |
Jiri Slaby | d6c53c0 | 2013-01-03 15:53:05 +0100 | [diff] [blame] | 470 | * function must not be called from IRQ context if port->low_latency is |
| 471 | * set. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 472 | * |
| 473 | * In the event of the queue being busy for flipping the work will be |
| 474 | * held off and retried later. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 475 | */ |
| 476 | |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 477 | void tty_flip_buffer_push(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 478 | { |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 479 | struct tty_bufhead *buf = &port->buf; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 480 | |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 481 | buf->tail->commit = buf->tail->used; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 482 | |
Jiri Slaby | 2e124b4 | 2013-01-03 15:53:06 +0100 | [diff] [blame] | 483 | if (port->low_latency) |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 484 | flush_to_ldisc(&buf->work); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 485 | else |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 486 | schedule_work(&buf->work); |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 487 | } |
| 488 | EXPORT_SYMBOL(tty_flip_buffer_push); |
| 489 | |
| 490 | /** |
| 491 | * tty_buffer_init - prepare a tty buffer structure |
| 492 | * @tty: tty to initialise |
| 493 | * |
| 494 | * Set up the initial state of the buffer management for a tty device. |
| 495 | * Must be called before the other tty buffer functions are used. |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 496 | */ |
| 497 | |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 498 | void tty_buffer_init(struct tty_port *port) |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 499 | { |
Jiri Slaby | ecbbfd4 | 2012-10-18 22:26:47 +0200 | [diff] [blame] | 500 | struct tty_bufhead *buf = &port->buf; |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 501 | |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 502 | mutex_init(&buf->lock); |
Peter Hurley | 7391ee1 | 2013-06-15 09:36:07 -0400 | [diff] [blame] | 503 | tty_buffer_reset(&buf->sentinel, 0); |
| 504 | buf->head = &buf->sentinel; |
| 505 | buf->tail = &buf->sentinel; |
Peter Hurley | 809850b | 2013-06-15 09:36:06 -0400 | [diff] [blame] | 506 | init_llist_head(&buf->free); |
Peter Hurley | 5dda4ca | 2013-11-22 12:09:56 -0500 | [diff] [blame] | 507 | atomic_set(&buf->mem_used, 0); |
Peter Hurley | a7c8d58 | 2013-06-15 09:36:15 -0400 | [diff] [blame] | 508 | atomic_set(&buf->priority, 0); |
Jiri Slaby | 5cff39c | 2012-10-18 22:26:45 +0200 | [diff] [blame] | 509 | INIT_WORK(&buf->work, flush_to_ldisc); |
Peter Hurley | 4d18e6ef | 2013-11-22 12:09:55 -0500 | [diff] [blame] | 510 | buf->mem_limit = TTYB_DEFAULT_MEM_LIMIT; |
Alan Cox | e049573 | 2008-10-13 10:36:58 +0100 | [diff] [blame] | 511 | } |
Peter Hurley | 4d18e6ef | 2013-11-22 12:09:55 -0500 | [diff] [blame] | 512 | |
| 513 | /** |
| 514 | * tty_buffer_set_limit - change the tty buffer memory limit |
| 515 | * @port: tty port to change |
| 516 | * |
| 517 | * Change the tty buffer memory limit. |
| 518 | * Must be called before the other tty buffer functions are used. |
| 519 | */ |
| 520 | |
| 521 | int tty_buffer_set_limit(struct tty_port *port, int limit) |
| 522 | { |
| 523 | if (limit < MIN_TTYB_SIZE) |
| 524 | return -EINVAL; |
| 525 | port->buf.mem_limit = limit; |
| 526 | return 0; |
| 527 | } |
| 528 | EXPORT_SYMBOL_GPL(tty_buffer_set_limit); |