From 0b05abe7bf9a46915bc1823753fc29c0a7b99ed1 Mon Sep 17 00:00:00 2001 From: Phil Yang Date: Mon, 8 Oct 2018 17:11:44 +0800 Subject: [PATCH] kni: fix FIFO synchronization 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: 3fc5ca2f6352 ("kni: initial import") Cc: stable@dpdk.org Signed-off-by: Phil Yang Reviewed-by: Honnappa Nagarahalli Reviewed-by: Gavin Hu Reviewed-by: Ola Liljedahl Reviewed-by: Jerin Jacob Reviewed-by: Ferruh Yigit --- 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 ac26a8c0b1..70ac14eec2 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); } -- 2.20.1