From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49530) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dACoW-0000Xr-IY for qemu-devel@nongnu.org; Mon, 15 May 2017 06:01:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dACoV-0005tf-7x for qemu-devel@nongnu.org; Mon, 15 May 2017 06:01:16 -0400 From: Paolo Bonzini Date: Mon, 15 May 2017 12:00:54 +0200 Message-Id: <20170515100059.15795-3-pbonzini@redhat.com> In-Reply-To: <20170515100059.15795-1-pbonzini@redhat.com> References: <20170515100059.15795-1-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH v3 2/7] curl: never invoke callbacks with s->mutex held List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: jcody@redhat.com, rjones@redhat.com, qemu-block@nongnu.org, qemu-stable@nongnu.org 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 --- block/curl.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/block/curl.c b/block/curl.c index 010b0604c5..924c2a2088 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: -- 2.12.2