Re: [PATCH v3 2/5] blkdebug: move post-resume handling to resume_req_by_tag

2021-05-31 Thread Vladimir Sementsov-Ogievskiy

17.05.2021 17:50, Emanuele Giuseppe Esposito wrote:

We want to move qemu_coroutine_yield() after the loop on rules,
because QLIST_FOREACH_SAFE is wrong if the rule list is modified
while the coroutine has yielded.  Therefore move the suspended
request to the heap and clean it up from the remove side.
All that is left is for blkdebug_debug_event to handle the
yielding.

Co-developed-by: Paolo Bonzini
Signed-off-by: Emanuele Giuseppe Esposito



Reviewed-by: Vladimir Sementsov-Ogievskiy 

--
Best regards,
Vladimir



[PATCH v3 2/5] blkdebug: move post-resume handling to resume_req_by_tag

2021-05-17 Thread Emanuele Giuseppe Esposito
We want to move qemu_coroutine_yield() after the loop on rules,
because QLIST_FOREACH_SAFE is wrong if the rule list is modified
while the coroutine has yielded.  Therefore move the suspended
request to the heap and clean it up from the remove side.
All that is left is for blkdebug_debug_event to handle the
yielding.

Co-developed-by: Paolo Bonzini 
Signed-off-by: Emanuele Giuseppe Esposito 
---
 block/blkdebug.c | 31 ++-
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/block/blkdebug.c b/block/blkdebug.c
index 8f19d991fa..e37f999254 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -775,25 +775,20 @@ static void blkdebug_close(BlockDriverState *bs)
 static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)
 {
 BDRVBlkdebugState *s = bs->opaque;
-BlkdebugSuspendedReq r;
+BlkdebugSuspendedReq *r;
 
-r = (BlkdebugSuspendedReq) {
-.co = qemu_coroutine_self(),
-.tag= g_strdup(rule->options.suspend.tag),
-};
+r = g_new(BlkdebugSuspendedReq, 1);
+
+r->co = qemu_coroutine_self();
+r->tag= g_strdup(rule->options.suspend.tag);
 
 remove_rule(rule);
-QLIST_INSERT_HEAD(>suspended_reqs, , next);
+QLIST_INSERT_HEAD(>suspended_reqs, r, next);
 
 if (!qtest_enabled()) {
-printf("blkdebug: Suspended request '%s'\n", r.tag);
+printf("blkdebug: Suspended request '%s'\n", r->tag);
 }
 qemu_coroutine_yield();
-if (!qtest_enabled()) {
-printf("blkdebug: Resuming request '%s'\n", r.tag);
-}
-
-g_free(r.tag);
 }
 
 static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
@@ -875,8 +870,18 @@ static int resume_req_by_tag(BDRVBlkdebugState *s, const 
char *tag, bool all)
 retry:
 QLIST_FOREACH(r, >suspended_reqs, next) {
 if (!strcmp(r->tag, tag)) {
+Coroutine *co = r->co;
+
+if (!qtest_enabled()) {
+printf("blkdebug: Resuming request '%s'\n", r->tag);
+}
+
 QLIST_REMOVE(r, next);
-qemu_coroutine_enter(r->co);
+g_free(r->tag);
+g_free(r);
+
+qemu_coroutine_enter(co);
+
 if (all) {
 goto retry;
 }
-- 
2.30.2