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[PULL 1/6] blkdebug: refactor removal of a suspended request
From: |
Max Reitz |
Subject: |
[PULL 1/6] blkdebug: refactor removal of a suspended request |
Date: |
Mon, 19 Jul 2021 19:26:53 +0200 |
From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Extract to a separate function. Do not rely on FOREACH_SAFE, which is
only "safe" if the *current* node is removed---not if another node is
removed. Instead, just walk the entire list from the beginning when
asked to resume all suspended requests with a given tag.
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>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210614082931.24925-2-eesposit@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block/blkdebug.c | 33 ++++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)
diff --git a/block/blkdebug.c b/block/blkdebug.c
index 2c0b9b0ee8..5ccbfcab42 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -793,7 +793,6 @@ static void suspend_request(BlockDriverState *bs,
BlkdebugRule *rule)
printf("blkdebug: Resuming request '%s'\n", r.tag);
}
- QLIST_REMOVE(&r, next);
g_free(r.tag);
}
@@ -869,25 +868,40 @@ static int blkdebug_debug_breakpoint(BlockDriverState
*bs, const char *event,
return 0;
}
-static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
+static int resume_req_by_tag(BDRVBlkdebugState *s, const char *tag, bool all)
{
- BDRVBlkdebugState *s = bs->opaque;
- BlkdebugSuspendedReq *r, *next;
+ BlkdebugSuspendedReq *r;
- QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, next) {
+retry:
+ /*
+ * No need for _SAFE, since a different coroutine can remove another node
+ * (not the current one) in this list, and when the current one is removed
+ * the iteration starts back from beginning anyways.
+ */
+ QLIST_FOREACH(r, &s->suspended_reqs, next) {
if (!strcmp(r->tag, tag)) {
+ QLIST_REMOVE(r, next);
qemu_coroutine_enter(r->co);
+ if (all) {
+ goto retry;
+ }
return 0;
}
}
return -ENOENT;
}
+static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
+{
+ BDRVBlkdebugState *s = bs->opaque;
+
+ return resume_req_by_tag(s, tag, false);
+}
+
static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
const char *tag)
{
BDRVBlkdebugState *s = bs->opaque;
- BlkdebugSuspendedReq *r, *r_next;
BlkdebugRule *rule, *next;
int i, ret = -ENOENT;
@@ -900,11 +914,8 @@ static int
blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
}
}
}
- QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, r_next) {
- if (!strcmp(r->tag, tag)) {
- qemu_coroutine_enter(r->co);
- ret = 0;
- }
+ if (resume_req_by_tag(s, tag, true) == 0) {
+ ret = 0;
}
return ret;
}
--
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 <=
- [PULL 2/6] blkdebug: move post-resume handling to resume_req_by_tag, Max Reitz, 2021/07/19
- [PULL 3/6] blkdebug: track all actions, Max Reitz, 2021/07/19
- [PULL 4/6] blkdebug: do not suspend in the middle of QLIST_FOREACH_SAFE, 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 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