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authorJan Kara <jack@suse.cz>2014-10-30 20:43:38 +0100
committerZefan Li <lizefan@huawei.com>2015-02-02 17:05:17 +0800
commit14194d6c2736eb1129579814dabb6e1751c7c964 (patch)
tree6a47aea5edf3d44eeb2f0eb6d09de2bf9e8df6cc /fs
parent0ec7236b1a62c0308b1249c9304f23335a72902b (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>
Diffstat (limited to 'fs')
-rw-r--r--fs/ioprio.c14
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)