zram: use scnprintf() in attrs show() methods

sysfs.txt documentation lists the following requirements:

 - The buffer will always be PAGE_SIZE bytes in length. On i386, this
   is 4096.

 - show() methods should return the number of bytes printed into the
   buffer. This is the return value of scnprintf().

 - show() should always use scnprintf().

Use scnprintf() in show() functions.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index b0e7592c44d8..f1ff39a3d1c1 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -275,12 +275,14 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
 
         while (backends[i]) {
                 if (sysfs_streq(comp, backends[i]->name))
-                        sz += sprintf(buf + sz, "[%s] ", backends[i]->name);
+                        sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+                                        "[%s] ", backends[i]->name);
                 else
-                        sz += sprintf(buf + sz, "%s ", backends[i]->name);
+                        sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+                                        "%s ", backends[i]->name);
                 i++;
         }
-        sz += sprintf(buf + sz, "\n");
+        sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
         return sz;
 }