| Message ID | 20191104101811.GA20821@mwanda (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iocost: add a comment about locking in ioc_weight_write() | expand |
Dan Carpenter <dan.carpenter@oracle.com> writes: > It wasn't very clear that blkg_conf_prep() disables IRQ and that they > are enabled in blkg_conf_finish() so this patch adds a comment about it. > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Thanks, Dan! > --- > I don't know if it's too late to fold this in with the previous patch? > > block/blk-iocost.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/block/blk-iocost.c b/block/blk-iocost.c > index a7ed434eae03..c5a8703ca6aa 100644 > --- a/block/blk-iocost.c > +++ b/block/blk-iocost.c > @@ -2095,6 +2095,7 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, > return nbytes; > } > > + /* blkg_conf_prep() takes the q->queue_lock and disables IRQs */ > ret = blkg_conf_prep(blkcg, &blkcg_policy_iocost, buf, &ctx); > if (ret) > return ret; > @@ -2115,6 +2116,7 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, > weight_updated(iocg); > spin_unlock(&iocg->ioc->lock); > > + /* blkg_conf_finish() unlocks the q->queue_lock and enables IRQs */ > blkg_conf_finish(&ctx); > return nbytes;
diff --git a/block/blk-iocost.c b/block/blk-iocost.c index a7ed434eae03..c5a8703ca6aa 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -2095,6 +2095,7 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, return nbytes; } + /* blkg_conf_prep() takes the q->queue_lock and disables IRQs */ ret = blkg_conf_prep(blkcg, &blkcg_policy_iocost, buf, &ctx); if (ret) return ret; @@ -2115,6 +2116,7 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, weight_updated(iocg); spin_unlock(&iocg->ioc->lock); + /* blkg_conf_finish() unlocks the q->queue_lock and enables IRQs */ blkg_conf_finish(&ctx); return nbytes;
It wasn't very clear that blkg_conf_prep() disables IRQ and that they are enabled in blkg_conf_finish() so this patch adds a comment about it. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- I don't know if it's too late to fold this in with the previous patch? block/blk-iocost.c | 2 ++ 1 file changed, 2 insertions(+)