From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 5324D1B8C8; Wed, 27 Jun 2018 11:44:28 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jun 2018 02:44:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,278,1526367600"; d="scan'208";a="66720547" Received: from irvmail001.ir.intel.com ([163.33.26.43]) by fmsmga004.fm.intel.com with ESMTP; 27 Jun 2018 02:44:26 -0700 Received: from sivswdev01.ir.intel.com (sivswdev01.ir.intel.com [10.237.217.45]) by irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id w5R9iPT8025963; Wed, 27 Jun 2018 10:44:25 +0100 Received: from sivswdev01.ir.intel.com (localhost [127.0.0.1]) by sivswdev01.ir.intel.com with ESMTP id w5R9iPRN014459; Wed, 27 Jun 2018 10:44:25 +0100 Received: (from aburakov@localhost) by sivswdev01.ir.intel.com with LOCAL id w5R9iPIp014455; Wed, 27 Jun 2018 10:44:25 +0100 From: Anatoly Burakov To: dev@dpdk.org Cc: qi.z.zhang@intel.com, stable@dpdk.org Date: Wed, 27 Jun 2018 10:44:25 +0100 Message-Id: <164824cc66c16755416bb8d3d6911385f52f8c1e.1530092380.git.anatoly.burakov@intel.com> X-Mailer: git-send-email 1.7.0.7 Subject: [dpdk-dev] [PATCH] ipc: fix locking while sending messages X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jun 2018 09:44:29 -0000 Previously, we were putting an exclusive lock to prevent secondary processes spinning up while we are sending our messages. However, using exclusive locks had an effect of disallowing multiple simultaenous unrelated messages/requests being sent, which was not the intention behind locking. Fix it to put a shared lock on the directory. That way, we still prevent secondary process initializations while sending data over IPC, but allow multiple unrelated transmissions to proceed. Fixes: 89f1fe7e6d95 ("eal: lock IPC directory on init and send") Cc: stable@dpdk.org Signed-off-by: Anatoly Burakov --- Notes: This patch is needed for multiprocess hotplug support [1], to avoid cases where multiple requests deadlock while in progress. [1] http://patches.dpdk.org/project/dpdk/list/?series=252 lib/librte_eal/common/eal_common_proc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/librte_eal/common/eal_common_proc.c b/lib/librte_eal/common/eal_common_proc.c index 707d8ab30..f010ef59e 100644 --- a/lib/librte_eal/common/eal_common_proc.c +++ b/lib/librte_eal/common/eal_common_proc.c @@ -786,7 +786,7 @@ mp_send(struct rte_mp_msg *msg, const char *peer, int type) dir_fd = dirfd(mp_dir); /* lock the directory to prevent processes spinning up while we send */ - if (flock(dir_fd, LOCK_EX)) { + if (flock(dir_fd, LOCK_SH)) { RTE_LOG(ERR, EAL, "Unable to lock directory %s\n", mp_dir_path); rte_errno = errno; @@ -1020,7 +1020,7 @@ rte_mp_request_sync(struct rte_mp_msg *req, struct rte_mp_reply *reply, dir_fd = dirfd(mp_dir); /* lock the directory to prevent processes spinning up while we send */ - if (flock(dir_fd, LOCK_EX)) { + if (flock(dir_fd, LOCK_SH)) { RTE_LOG(ERR, EAL, "Unable to lock directory %s\n", mp_dir_path); closedir(mp_dir); @@ -1146,7 +1146,7 @@ rte_mp_request_async(struct rte_mp_msg *req, const struct timespec *ts, dir_fd = dirfd(mp_dir); /* lock the directory to prevent processes spinning up while we send */ - if (flock(dir_fd, LOCK_EX)) { + if (flock(dir_fd, LOCK_SH)) { RTE_LOG(ERR, EAL, "Unable to lock directory %s\n", mp_dir_path); rte_errno = errno; -- 2.17.1