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>
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);
};
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);
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;
}