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| author |   Coly Li <colyli@suse.de> | 2018-08-10 23:45:50 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2018-08-10 12:18:47 -0600 |
| commit | 46451874c7c9afaa4e014aea0f0970f886444e0d (patch) | |
| tree | 4c9629924666c0c27a213f8f81293087afaad268 /drivers/md/bcache/sysfs.c | |
| parent | null_blk: add lock drop/acquire annotation (diff) | |
| download | linux-dev-46451874c7c9afaa4e014aea0f0970f886444e0d.tar.xz linux-dev-46451874c7c9afaa4e014aea0f0970f886444e0d.zip | |
bcache: fix error setting writeback_rate through sysfs interface
Commit ea8c5356d390 ("bcache: set max writeback rate when I/O request
is idle") changes struct bch_ratelimit member rate from uint32_t to
atomic_long_t and uses atomic_long_set() in drivers/md/bcache/sysfs.c
to set new writeback rate, after the input is converted from memory
buf to long int by sysfs_strtoul_clamp().
The above change has a problem because there is an implicit return
inside sysfs_strtoul_clamp() so the following atomic_long_set()
won't be called. This error is detected by 0day system with following
snipped smatch warnings:
drivers/md/bcache/sysfs.c:271 __cached_dev_store() error: uninitialized
symbol 'v'.
270 sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@271 atomic_long_set(&dc->writeback_rate.rate, v);
This patch fixes the above error by using strtoul_safe_clamp() to
convert the input buffer into a long int type result.
Fixes: ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle")
Cc: Kai Krakow <kai@kaishome.de>
Cc: Stefan Priebe <s.priebe@profihost.ag>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache/sysfs.c')
| -rw-r--r-- | drivers/md/bcache/sysfs.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index 22f8565d2bf1..81d3520b0702 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -265,10 +265,17 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40); if (attr == &sysfs_writeback_rate) { - int v; + ssize_t ret; + long int v = atomic_long_read(&dc->writeback_rate.rate); + + ret = strtoul_safe_clamp(buf, v, 1, INT_MAX); - sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX); - atomic_long_set(&dc->writeback_rate.rate, v); + if (!ret) { + atomic_long_set(&dc->writeback_rate.rate, v); + ret = size; + } + + return ret; } sysfs_strtoul_clamp(writeback_rate_update_seconds, |