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[PULL 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE
From: |
Max Reitz |
Subject: |
[PULL 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE |
Date: |
Mon, 19 Jul 2021 19:26:56 +0200 |
From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
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>
Message-Id: <20210614082931.24925-5-eesposit@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.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
- [PULL 0/6] Block patches for 6.1-rc0, Max Reitz, 2021/07/19
- [PULL 1/6] blkdebug: refactor removal of a suspended request, Max Reitz, 2021/07/19
- [PULL 3/6] blkdebug: track all actions, Max Reitz, 2021/07/19
- [PULL 2/6] blkdebug: move post-resume handling to resume_req_by_tag, Max Reitz, 2021/07/19
- [PULL 5/6] block/blkdebug: remove new_state field and instead use a local variable, Max Reitz, 2021/07/19
- [PULL 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE,
Max Reitz <=
- [PULL 6/6] blkdebug: protect rules and suspended_reqs with a lock, Max Reitz, 2021/07/19
- Re: [PULL 0/6] Block patches for 6.1-rc0, Peter Maydell, 2021/07/20