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authorJan Kara <jack@suse.cz>2014-10-30 20:43:38 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-21 09:22:53 -0800
commit9d0c27027cba7de2e42695d7bd29fa42666dac63 (patch)
tree525bd3e1d60e3bba41faac822fab37aa63cd2a27 /fs
parentaca0ab61812decb0bd0335fc9c4b065991884b66 (diff)
downloadlinux-linaro-stable-9d0c27027cba7de2e42695d7bd29fa42666dac63.tar.gz
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 e50170ca7c33..31666c92b46a 100644
--- a/fs/ioprio.c
+++ b/fs/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)