* [PATCHv2] zram: check comp algorithm availability earlier
@ 2015-05-27 11:20 Sergey Senozhatsky
2015-05-27 13:32 ` Minchan Kim
0 siblings, 1 reply; 2+ messages in thread
From: Sergey Senozhatsky @ 2015-05-27 11:20 UTC (permalink / raw)
To: Andrew Morton, Minchan Kim
Cc: Marcin Jabrzyk, Nitin Gupta, linux-kernel, Sergey Senozhatsky,
Sergey Senozhatsky
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>
---
drivers/block/zram/zcomp.c | 5 +++++
drivers/block/zram/zcomp.h | 1 +
drivers/block/zram/zram_drv.c | 3 +++
3 files changed, 9 insertions(+)
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index a1a8b8e..965d1af 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 c59d1fc..46e2b9f 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 28f6e46..1cd8ade 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;
}
--
2.4.1.314.g9532ead
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCHv2] zram: check comp algorithm availability earlier
2015-05-27 11:20 [PATCHv2] zram: check comp algorithm availability earlier Sergey Senozhatsky
@ 2015-05-27 13:32 ` Minchan Kim
0 siblings, 0 replies; 2+ messages in thread
From: Minchan Kim @ 2015-05-27 13:32 UTC (permalink / raw)
To: Sergey Senozhatsky
Cc: Andrew Morton, Marcin Jabrzyk, Nitin Gupta, linux-kernel,
Sergey Senozhatsky
On Wed, May 27, 2015 at 08:20:12PM +0900, Sergey Senozhatsky wrote:
> 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>
Thanks.
--
Kind regards,
Minchan Kim
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2015-05-27 13:32 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-05-27 11:20 [PATCHv2] zram: check comp algorithm availability earlier Sergey Senozhatsky
2015-05-27 13:32 ` Minchan Kim
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).