tree 0eee23d9451b404c4f2aa9ad7e6a6fe970806cae
parent 4bbacd51a683e45c13f7d6df6f85cb7391590311
author Sergey Senozhatsky <sergey.senozhatsky@gmail.com> 1435269632 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1435276837 -0700

zram: check comp algorithm availability earlier

Improvement idea by Marcin Jabrzyk.

comp_algorithm_store() silently accepts any supplied algorithm name,
because zram performs algorithm availability check later, during the
device configuration phase in disksize_store() and emits the following
error:

  "zram: Cannot initialise %s compressing backend"

this error line is somewhat generic and, besides, can indicate a failed
attempt to allocate compression backend's working buffers.

add algorithm availability check to comp_algorithm_store():

  echo lzz > /sys/block/zram0/comp_algorithm
  -bash: echo: write error: Invalid argument

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Marcin Jabrzyk <m.jabrzyk@samsung.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>