diff options
| author | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2015-06-25 15:00:32 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-25 17:00:37 -0700 |
| commit | d93435c3fba4a47b773693b0c8992470d38510d5 (patch) | |
| tree | 0eee23d9451b404c4f2aa9ad7e6a6fe970806cae | |
| parent | 4bbacd51a683e45c13f7d6df6f85cb7391590311 (diff) | |
| download | lwn-d93435c3fba4a47b773693b0c8992470d38510d5.tar.gz lwn-d93435c3fba4a47b773693b0c8992470d38510d5.zip | |
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>
| -rw-r--r-- | drivers/block/zram/zcomp.c | 5 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.h | 1 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 3 |
3 files changed, 9 insertions, 0 deletions
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index a1a8b8ee9fda..965d1afb0eaa 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -286,6 +286,11 @@ ssize_t zcomp_available_show(const char *comp, char *buf) return sz; } +bool zcomp_available_algorithm(const char *comp) +{ + return find_backend(comp) != NULL; +} + bool zcomp_set_max_streams(struct zcomp *comp, int num_strm) { return comp->set_max_streams(comp, num_strm); diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index c59d1fca72c0..46e2b9f8f1f0 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -51,6 +51,7 @@ struct zcomp { }; ssize_t zcomp_available_show(const char *comp, char *buf); +bool zcomp_available_algorithm(const char *comp); struct zcomp *zcomp_create(const char *comp, int max_strm); void zcomp_destroy(struct zcomp *comp); diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index d94696b28a85..fb655e8d1e3b 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -378,6 +378,9 @@ static ssize_t comp_algorithm_store(struct device *dev, if (sz > 0 && zram->compressor[sz - 1] == '\n') zram->compressor[sz - 1] = 0x00; + if (!zcomp_available_algorithm(zram->compressor)) + len = -EINVAL; + up_write(&zram->init_lock); return len; } |