From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46779) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dAeoC-0003U8-CC for qemu-devel@nongnu.org; Tue, 16 May 2017 11:54:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dAeoB-0001dU-C7 for qemu-devel@nongnu.org; Tue, 16 May 2017 11:54:48 -0400 From: Jeff Cody Date: Tue, 16 May 2017 11:54:15 -0400 Message-Id: <20170516155420.10106-4-jcody@redhat.com> In-Reply-To: <20170516155420.10106-1-jcody@redhat.com> References: <20170516155420.10106-1-jcody@redhat.com> Subject: [Qemu-devel] [PULL 3/8] curl: never invoke callbacks with s->mutex held List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: peter.maydell@linaro.org, jcody@redhat.com, qemu-devel@nongnu.org, Paolo Bonzini , qemu-stable@nongnu.org From: Paolo Bonzini 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 --- block/curl.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/block/curl.c b/block/curl.c index 562340f..18b82bc 100644 --- a/block/curl.c +++ b/block/curl.c @@ -148,6 +148,7 @@ 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; @@ -164,6 +165,7 @@ 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) { @@ -213,6 +215,7 @@ 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; @@ -227,6 +230,7 @@ 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); @@ -265,7 +269,9 @@ 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; } @@ -306,8 +312,6 @@ 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; } @@ -854,8 +858,8 @@ 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: -- 2.9.3