proc: move pagecount stuff to fs/proc/page.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
diff --git a/fs/proc/page.c b/fs/proc/page.c
new file mode 100644
index 0000000..767d95a
--- /dev/null
+++ b/fs/proc/page.c
@@ -0,0 +1,147 @@
+#include <linux/bootmem.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+#define KPMSIZE sizeof(u64)
+#define KPMMASK (KPMSIZE - 1)
+/* /proc/kpagecount - an array exposing page counts
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page count.
+ */
+static ssize_t kpagecount_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 pcount;
+
+ pfn = src / KPMSIZE;
+ count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+
+ while (count > 0) {
+ ppage = NULL;
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ pfn++;
+ if (!ppage)
+ pcount = 0;
+ else
+ pcount = page_mapcount(ppage);
+
+ if (put_user(pcount, out++)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ count -= KPMSIZE;
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct file_operations proc_kpagecount_operations = {
+ .llseek = mem_lseek,
+ .read = kpagecount_read,
+};
+
+/* /proc/kpageflags - an array exposing page flags
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page flags.
+ */
+
+/* These macros are used to decouple internal flags from exported ones */
+
+#define KPF_LOCKED 0
+#define KPF_ERROR 1
+#define KPF_REFERENCED 2
+#define KPF_UPTODATE 3
+#define KPF_DIRTY 4
+#define KPF_LRU 5
+#define KPF_ACTIVE 6
+#define KPF_SLAB 7
+#define KPF_WRITEBACK 8
+#define KPF_RECLAIM 9
+#define KPF_BUDDY 10
+
+#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos)
+
+static ssize_t kpageflags_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 kflags, uflags;
+
+ pfn = src / KPMSIZE;
+ count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+
+ while (count > 0) {
+ ppage = NULL;
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ pfn++;
+ if (!ppage)
+ kflags = 0;
+ else
+ kflags = ppage->flags;
+
+ uflags = kpf_copy_bit(KPF_LOCKED, PG_locked, kflags) |
+ kpf_copy_bit(kflags, KPF_ERROR, PG_error) |
+ kpf_copy_bit(kflags, KPF_REFERENCED, PG_referenced) |
+ kpf_copy_bit(kflags, KPF_UPTODATE, PG_uptodate) |
+ kpf_copy_bit(kflags, KPF_DIRTY, PG_dirty) |
+ kpf_copy_bit(kflags, KPF_LRU, PG_lru) |
+ kpf_copy_bit(kflags, KPF_ACTIVE, PG_active) |
+ kpf_copy_bit(kflags, KPF_SLAB, PG_slab) |
+ kpf_copy_bit(kflags, KPF_WRITEBACK, PG_writeback) |
+ kpf_copy_bit(kflags, KPF_RECLAIM, PG_reclaim) |
+ kpf_copy_bit(kflags, KPF_BUDDY, PG_buddy);
+
+ if (put_user(uflags, out++)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ count -= KPMSIZE;
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct file_operations proc_kpageflags_operations = {
+ .llseek = mem_lseek,
+ .read = kpageflags_read,
+};
+
+static int __init proc_page_init(void)
+{
+ proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
+ proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
+ return 0;
+}
+module_init(proc_page_init);