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[PATCH v5 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_S
From: |
Emanuele Giuseppe Esposito |
Subject: |
[PATCH v5 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE |
Date: |
Mon, 14 Jun 2021 10:29:29 +0200 |
That would be unsafe in case a rule other than the current one
is removed while the coroutine has yielded.
Keep FOREACH_SAFE because suspend_request deletes the current rule.
After this patch, *all* matching rules are deleted before suspending
the coroutine, rather than just one.
This doesn't affect the existing testcases.
Use actions_count to see how many yield to issue.
Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block/blkdebug.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/block/blkdebug.c b/block/blkdebug.c
index 6bdeb2c7b3..dd82131d1e 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -789,7 +789,6 @@ static void suspend_request(BlockDriverState *bs,
BlkdebugRule *rule)
if (!qtest_enabled()) {
printf("blkdebug: Suspended request '%s'\n", r->tag);
}
- qemu_coroutine_yield();
}
static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
@@ -834,6 +833,12 @@ static void blkdebug_debug_event(BlockDriverState *bs,
BlkdebugEvent event)
QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {
process_rule(bs, rule, actions_count);
}
+
+ while (actions_count[ACTION_SUSPEND] > 0) {
+ qemu_coroutine_yield();
+ actions_count[ACTION_SUSPEND]--;
+ }
+
s->state = s->new_state;
}
--
2.31.1
- [PATCH v5 0/6] blkdebug: fix racing condition when iterating on, Emanuele Giuseppe Esposito, 2021/06/14
- [PATCH v5 1/6] blkdebug: refactor removal of a suspended request, Emanuele Giuseppe Esposito, 2021/06/14
- [PATCH v5 2/6] blkdebug: move post-resume handling to resume_req_by_tag, Emanuele Giuseppe Esposito, 2021/06/14
- [PATCH v5 3/6] blkdebug: track all actions, Emanuele Giuseppe Esposito, 2021/06/14
- [PATCH v5 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE,
Emanuele Giuseppe Esposito <=
- [PATCH v5 6/6] blkdebug: protect rules and suspended_reqs with a lock, Emanuele Giuseppe Esposito, 2021/06/14
- [PATCH v5 5/6] block/blkdebug: remove new_state field and instead use a local variable, Emanuele Giuseppe Esposito, 2021/06/14