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| author | Jan Kara <jack@suse.cz> | 2014-10-30 20:43:38 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-10-31 08:30:43 -0600 |
| commit | ece9c72accdc45c3a9484dacb1125ce572647288 (patch) | |
| tree | 9951eb6b877628b60562f4cc5ee80099f501d736 /block/ioprio.c | |
| parent | 3a2f22b7d0cc64482a91529e23c2570aa0602fa6 (diff) | |
| download | lwn-ece9c72accdc45c3a9484dacb1125ce572647288.tar.gz lwn-ece9c72accdc45c3a9484dacb1125ce572647288.zip | |
block: Fix computation of merged request priority
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
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/ioprio.c')
| -rw-r--r-- | block/ioprio.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/block/ioprio.c b/block/ioprio.c index e50170ca7c33..31666c92b46a 100644 --- a/block/ioprio.c +++ b/block/ioprio.c @@ -157,14 +157,16 @@ 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) |