From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Yang Subject: [PATCH v3 2/4] kni: fix kni fifo synchronization Date: Mon, 8 Oct 2018 17:11:44 +0800 Message-ID: <1538989906-8349-2-git-send-email-phil.yang@arm.com> References: <1537364560-4124-1-git-send-email-phil.yang@arm.com> <1538989906-8349-1-git-send-email-phil.yang@arm.com> Cc: jerin.jacob@caviumnetworks.com, Gavin.Hu@arm.com, Honnappa.Nagarahalli@arm.com, Ola.Liljedahl@arm.com, ferruh.yigit@intel.com, phil.yang@arm.com To: dev@dpdk.org Return-path: Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by dpdk.org (Postfix) with ESMTP id CDACD4C80 for ; Mon, 8 Oct 2018 11:11:59 +0200 (CEST) In-Reply-To: <1538989906-8349-1-git-send-email-phil.yang@arm.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" With existing code in kni_fifo_put, rx_q values are not being updated before updating fifo_write. While reading rx_q in kni_net_rx_normal, This is causing the sync issue on other core. The same situation happens in kni_fifo_get as well. So syncing the values by adding memory barriers to make sure the values being synced before updating fifo_write and fifo_read. Fixes: 3fc5ca2 ("kni: initial import") Signed-off-by: Phil Yang Reviewed-by: Honnappa Nagarahalli Reviewed-by: Gavin Hu Reviewed-by: Ola Liljedahl Reviewed-by: Jerin Jacob --- lib/librte_kni/rte_kni_fifo.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/lib/librte_kni/rte_kni_fifo.h b/lib/librte_kni/rte_kni_fifo.h index ac26a8c..70ac14e 100644 --- a/lib/librte_kni/rte_kni_fifo.h +++ b/lib/librte_kni/rte_kni_fifo.h @@ -28,8 +28,9 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num) { unsigned i = 0; unsigned fifo_write = fifo->write; - unsigned fifo_read = fifo->read; unsigned new_write = fifo_write; + rte_smp_rmb(); + unsigned fifo_read = fifo->read; for (i = 0; i < num; i++) { new_write = (new_write + 1) & (fifo->len - 1); @@ -39,6 +40,7 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num) fifo->buffer[fifo_write] = data[i]; fifo_write = new_write; } + rte_smp_wmb(); fifo->write = fifo_write; return i; } @@ -51,7 +53,9 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num) { unsigned i = 0; unsigned new_read = fifo->read; + rte_smp_rmb(); unsigned fifo_write = fifo->write; + for (i = 0; i < num; i++) { if (new_read == fifo_write) break; @@ -59,6 +63,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num) data[i] = fifo->buffer[new_read]; new_read = (new_read + 1) & (fifo->len - 1); } + rte_smp_rmb(); fifo->read = new_read; return i; } @@ -69,5 +74,8 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num) static inline uint32_t kni_fifo_count(struct rte_kni_fifo *fifo) { - return (fifo->len + fifo->write - fifo->read) & (fifo->len - 1); + unsigned fifo_write = fifo->write; + rte_smp_rmb(); + unsigned fifo_read = fifo->read; + return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1); } -- 2.7.4