From 96b7b5da2f485e7e9d76b5528f917d6f7e169a64 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 17 May 2017 13:09:16 +0200 Subject: [PATCH 10/27] curl: never invoke callbacks with s->mutex held RH-Author: Paolo Bonzini Message-id: <20170517130921.27402-3-pbonzini@redhat.com> Patchwork-id: 75262 O-Subject: [RHEL7.4 qemu-kvm PATCH v2 2/7] curl: never invoke callbacks with s->mutex held Bugzilla: 1437393 RH-Acked-by: Max Reitz RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Jeffrey Cody All curl callbacks go through curl_multi_do, and hence are called with s->mutex held. Note that with comments, and make curl_read_cb drop the lock before invoking the callback. Likewise for curl_find_buf, where the callback can be invoked by the caller. Cc: qemu-stable@nongnu.org Reviewed-by: Jeff Cody Signed-off-by: Paolo Bonzini Reviewed-by: Max Reitz Message-id: 20170515100059.15795-3-pbonzini@redhat.com Signed-off-by: Jeff Cody (cherry picked from commit 34db05e7ffe8d61ca7288b9532ad6e8300853318) Signed-off-by: Miroslav Rezanina --- block/curl.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/block/curl.c b/block/curl.c index e77a64b..94a1e16 100644 --- a/block/curl.c +++ b/block/curl.c @@ -147,6 +147,7 @@ static void curl_multi_do(void *arg); static void curl_multi_read(void *arg); #ifdef NEED_CURL_TIMER_CALLBACK +/* Called from curl_multi_do_locked, with s->mutex held. */ static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque) { BDRVCURLState *s = opaque; @@ -163,6 +164,7 @@ static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque) } #endif +/* Called from curl_multi_do_locked, with s->mutex held. */ static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action, void *userp, void *sp) { @@ -212,6 +214,7 @@ static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action, return 0; } +/* Called from curl_multi_do_locked, with s->mutex held. */ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque) { BDRVCURLState *s = opaque; @@ -226,6 +229,7 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque) return realsize; } +/* Called from curl_multi_do_locked, with s->mutex held. */ static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque) { CURLState *s = ((CURLState*)opaque); @@ -264,7 +268,9 @@ static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque) request_length - offset); } + qemu_mutex_unlock(&s->s->mutex); acb->common.cb(acb->common.opaque, 0); + qemu_mutex_lock(&s->s->mutex); qemu_aio_unref(acb); s->acb[i] = NULL; } @@ -305,8 +311,6 @@ static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len, if (clamped_len < len) { qemu_iovec_memset(acb->qiov, clamped_len, 0, len - clamped_len); } - acb->common.cb(acb->common.opaque, 0); - return FIND_RET_OK; } @@ -832,8 +836,8 @@ static void curl_readv_bh_cb(void *p) // we can just call the callback and be done. switch (curl_find_buf(s, start, acb->nb_sectors * BDRV_SECTOR_SIZE, acb)) { case FIND_RET_OK: - qemu_aio_unref(acb); - // fall through + ret = 0; + goto out; case FIND_RET_WAIT: goto out; default: -- 1.8.3.1