diff options
| author | Jan Kara <jack@suse.cz> | 2014-10-30 20:43:38 +0100 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-02-02 17:05:17 +0800 |
| commit | 14194d6c2736eb1129579814dabb6e1751c7c964 (patch) | |
| tree | 6a47aea5edf3d44eeb2f0eb6d09de2bf9e8df6cc | |
| parent | 0ec7236b1a62c0308b1249c9304f23335a72902b (diff) | |
block: Fix computation of merged request priority
commit ece9c72accdc45c3a9484dacb1125ce572647288 upstream.
Priority of a merged request is computed by ioprio_best(). If one of the
requests has undefined priority (IOPRIO_CLASS_NONE) and another request
has priority from IOPRIO_CLASS_BE, the function will return the
undefined priority which is wrong. Fix the function to properly return
priority of a request with the defined priority.
Fixes: d58cdfb89ce0c6bd5f81ae931a984ef298dbda20
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
[lizf: Backported to 3.4: adjust filename]
Signed-off-by: Zefan Li <lizefan@huawei.com>
| -rw-r--r-- | fs/ioprio.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/fs/ioprio.c b/fs/ioprio.c index 0f1b9515213b..0dd6a2a7ae82 100644 --- a/fs/ioprio.c +++ b/fs/ioprio.c @@ -153,14 +153,16 @@ out: int ioprio_best(unsigned short aprio, unsigned short bprio) { - unsigned short aclass = IOPRIO_PRIO_CLASS(aprio); - unsigned short bclass = IOPRIO_PRIO_CLASS(bprio); + unsigned short aclass; + unsigned short bclass; - if (aclass == IOPRIO_CLASS_NONE) - aclass = IOPRIO_CLASS_BE; - if (bclass == IOPRIO_CLASS_NONE) - bclass = IOPRIO_CLASS_BE; + if (!ioprio_valid(aprio)) + aprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM); + if (!ioprio_valid(bprio)) + bprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM); + aclass = IOPRIO_PRIO_CLASS(aprio); + bclass = IOPRIO_PRIO_CLASS(bprio); if (aclass == bclass) return min(aprio, bprio); if (aclass > bclass) |