The patch titled
Subject: zram: check comp algorithm availability earlier
has been added to the -mm tree. Its filename is
zram-check-comp-algorithm-availability-earlier.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/zram-check-comp-algorithm-availability-earlier.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/zram-check-comp-algorithm-availability-earlier.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Subject: zram: check comp algorithm availability earlier
Improvement idea by Marcin Jabrzyk.
comp_algorithm_store() silently accepts any supplied algorithm name,
because zram performs the algorithm availability check later, during the
device configuration phase in disksize_store() and prints
"zram: Cannot initialise %s compressing backend"
to syslog. this error line is somewhat generic and, besides, can indicate
a failed attempt to allocate compression backend's working buffers.
Make algorithm availability check earlier, in comp_algorithm_store(), and
be move verbose:
echo lzz > /sys/block/zram0/comp_algorithm
-bash: echo: write error: Invalid argument
dmesg:
zram: Error: unavailable compression algorithm: lzz
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Reported-by: Marcin Jabrzyk <m.jabrzyk@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zcomp.c | 5 +++++
drivers/block/zram/zcomp.h | 1 +
drivers/block/zram/zram_drv.c | 6 ++++++
3 files changed, 12 insertions(+)
diff -puN drivers/block/zram/zcomp.c~zram-check-comp-algorithm-availability-earlier drivers/block/zram/zcomp.c
--- a/drivers/block/zram/zcomp.c~zram-check-comp-algorithm-availability-earlier
+++ a/drivers/block/zram/zcomp.c
@@ -320,6 +320,11 @@ void zcomp_destroy(struct zcomp *comp)
kfree(comp);
}
+bool zcomp_available_algorithm(const char *comp)
+{
+ return find_backend(comp) != NULL;
+}
+
/*
* search available compressors for requested algorithm.
* allocate new zcomp and initialize it. return compressing
diff -puN drivers/block/zram/zcomp.h~zram-check-comp-algorithm-availability-earlier drivers/block/zram/zcomp.h
--- a/drivers/block/zram/zcomp.h~zram-check-comp-algorithm-availability-earlier
+++ a/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 -puN drivers/block/zram/zram_drv.c~zram-check-comp-algorithm-availability-earlier drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-check-comp-algorithm-availability-earlier
+++ a/drivers/block/zram/zram_drv.c
@@ -378,6 +378,12 @@ static ssize_t comp_algorithm_store(stru
if (sz > 0 && zram->compressor[sz - 1] == '\n')
zram->compressor[sz - 1] = 0x00;
+ if (!zcomp_available_algorithm(zram->compressor)) {
+ pr_err("Error: unavailable compression algorithm: %s\n",
+ zram->compressor);
+ len = -EINVAL;
+ }
+
up_write(&zram->init_lock);
return len;
}
_
Patches currently in -mm which might be from sergey.senozhatsky@xxxxxxxxx are
zram-add-compact-sysfs-entry-to-documentation.patch
zram-cosmetic-zram_attr_ro-code-formatting-tweak.patch
zram-use-idr-instead-of-zram_devices-array.patch
zram-reorganize-code-layout.patch
zram-remove-max_num_devices-limitation.patch
zram-report-every-added-and-removed-device.patch
zram-trivial-correct-flag-operations-comment.patch
zram-return-zram-device_id-from-zram_add.patch
zram-close-race-by-open-overriding.patch
zram-add-dynamic-device-add-remove-functionality.patch
zram-cosmetic-zram_bvec_write-cleanup.patch
zram-cut-trailing-newline-in-algorithm-name.patch
zram-check-comp-algorithm-availability-earlier.patch
linux-next.patch
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