* [RESEND][PATCH v2] cfq: clear queue pointers from cfqg after unpinning them in cfq_pd_offline
@ 2018-10-10 21:16 Maciej S. Szmigiero
2018-10-11 17:46 ` Jens Axboe
0 siblings, 1 reply; 3+ messages in thread
From: Maciej S. Szmigiero @ 2018-10-10 21:16 UTC (permalink / raw)
To: Jens Axboe
Cc: Caspar Zhang, jiufei.xue, Tejun Heo, Joseph Qi, linux-kernel,
linux-block
BFQ is already doing a similar thing in its .pd_offline_fn() method
implementation.
While it seems that after commit 4c6994806f70
("blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()")
was reverted leaving these pointers intact no longer causes crashes
clearing them is still a sensible thing to do to make the code more robust.
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
---
Changes from v1: Drop stable and fixes tags, rewrite the commit message
as after commit 4c6994806f70 was reverted this change is no longer
required to fix a crash.
block/cfq-iosched.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d219e9a1af65..6a3d87dd3c1a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1644,14 +1644,20 @@ static void cfq_pd_offline(struct blkg_policy_data *pd)
int i;
for (i = 0; i < IOPRIO_BE_NR; i++) {
- if (cfqg->async_cfqq[0][i])
+ if (cfqg->async_cfqq[0][i]) {
cfq_put_queue(cfqg->async_cfqq[0][i]);
- if (cfqg->async_cfqq[1][i])
+ cfqg->async_cfqq[0][i] = NULL;
+ }
+ if (cfqg->async_cfqq[1][i]) {
cfq_put_queue(cfqg->async_cfqq[1][i]);
+ cfqg->async_cfqq[1][i] = NULL;
+ }
}
- if (cfqg->async_idle_cfqq)
+ if (cfqg->async_idle_cfqq) {
cfq_put_queue(cfqg->async_idle_cfqq);
+ cfqg->async_idle_cfqq = NULL;
+ }
/*
* @blkg is going offline and will be ignored by
--
2.17.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RESEND][PATCH v2] cfq: clear queue pointers from cfqg after unpinning them in cfq_pd_offline
2018-10-10 21:16 [RESEND][PATCH v2] cfq: clear queue pointers from cfqg after unpinning them in cfq_pd_offline Maciej S. Szmigiero
@ 2018-10-11 17:46 ` Jens Axboe
0 siblings, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2018-10-11 17:46 UTC (permalink / raw)
To: Maciej S. Szmigiero
Cc: Caspar Zhang, jiufei.xue, Tejun Heo, Joseph Qi, linux-kernel,
linux-block
On 10/10/18 3:16 PM, Maciej S. Szmigiero wrote:
> BFQ is already doing a similar thing in its .pd_offline_fn() method
> implementation.
>
> While it seems that after commit 4c6994806f70
> ("blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()")
> was reverted leaving these pointers intact no longer causes crashes
> clearing them is still a sensible thing to do to make the code more robust.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
* [RESEND][PATCH v2] cfq: clear queue pointers from cfqg after unpinning them in cfq_pd_offline
@ 2018-09-19 21:58 Maciej S. Szmigiero
0 siblings, 0 replies; 3+ messages in thread
From: Maciej S. Szmigiero @ 2018-09-19 21:58 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-block, linux-kernel, Joseph Qi, Tejun Heo, jiufei.xue,
Caspar Zhang
BFQ is already doing a similar thing in its .pd_offline_fn() method
implementation.
While it seems that after
commit 4c6994806f70 ("blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()")
was reverted leaving these pointers intact no longer causes crashes
clearing them is still a sensible thing to do to make the code more robust.
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
---
Changes from v1: Drop stable and fixes tags, rewrite the commit message
as after commit 4c6994806f70 was reverted this change is no longer
required to fix a crash.
block/cfq-iosched.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 2eb87444b157..ed41aa978c4a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1644,14 +1644,20 @@ static void cfq_pd_offline(struct blkg_policy_data *pd)
int i;
for (i = 0; i < IOPRIO_BE_NR; i++) {
- if (cfqg->async_cfqq[0][i])
+ if (cfqg->async_cfqq[0][i]) {
cfq_put_queue(cfqg->async_cfqq[0][i]);
- if (cfqg->async_cfqq[1][i])
+ cfqg->async_cfqq[0][i] = NULL;
+ }
+ if (cfqg->async_cfqq[1][i]) {
cfq_put_queue(cfqg->async_cfqq[1][i]);
+ cfqg->async_cfqq[1][i] = NULL;
+ }
}
- if (cfqg->async_idle_cfqq)
+ if (cfqg->async_idle_cfqq) {
cfq_put_queue(cfqg->async_idle_cfqq);
+ cfqg->async_idle_cfqq = NULL;
+ }
/*
* @blkg is going offline and will be ignored by
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2018-10-10 21:16 [RESEND][PATCH v2] cfq: clear queue pointers from cfqg after unpinning them in cfq_pd_offline Maciej S. Szmigiero
2018-10-11 17:46 ` Jens Axboe
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2018-09-19 21:58 Maciej S. Szmigiero
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