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From: <shaibran@amazon.com>
To: <ferruh.yigit@amd.com>
Cc: <dev@dpdk.org>, Shai Brandes <shaibran@amazon.com>
Subject: [PATCH v4 19/31] net/ena/base: modify memory barrier comment
Date: Tue, 12 Mar 2024 20:07:04 +0200	[thread overview]
Message-ID: <20240312180716.8515-20-shaibran@amazon.com> (raw)
In-Reply-To: <20240312180716.8515-1-shaibran@amazon.com>

From: Shai Brandes <shaibran@amazon.com>

The dma_rmb() memory barrier guarantees that the device set the
phase bit before continuing to read the rest of the descriptor.
Because the phase bit and the rest of the descriptor are in the same
cache line this ensures coherency of the data from the descriptor.

Signed-off-by: Shai Brandes <shaibran@amazon.com>
Reviewed-by: Amit Bernstein <amitbern@amazon.com>
---
 drivers/net/ena/base/ena_com.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ena/base/ena_com.c b/drivers/net/ena/base/ena_com.c
index f9613f7807..053e095585 100644
--- a/drivers/net/ena/base/ena_com.c
+++ b/drivers/net/ena/base/ena_com.c
@@ -2412,8 +2412,8 @@ void ena_com_aenq_intr_handler(struct ena_com_dev *ena_dev, void *data)
 	/* Go over all the events */
 	while ((READ_ONCE8(aenq_common->flags) &
 		ENA_ADMIN_AENQ_COMMON_DESC_PHASE_MASK) == phase) {
-		/* Make sure the phase bit (ownership) is as expected before
-		 * reading the rest of the descriptor.
+		/* Make sure the device finished writing the rest of the descriptor
+		 * before reading it.
 		 */
 		dma_rmb();
 
-- 
2.17.1


  parent reply	other threads:[~2024-03-12 18:09 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-12 18:06 [PATCH v4 00/31] net/ena: v2.9.0 driver release shaibran
2024-03-12 18:06 ` [PATCH v4 01/31] net/ena: rework the metrics multi-process functions shaibran
2024-03-12 18:06 ` [PATCH v4 02/31] net/ena: report new supported link speed capabilities shaibran
2024-03-12 18:06 ` [PATCH v4 03/31] net/ena: update imissed stat with Rx overruns shaibran
2024-03-13 15:59   ` Ferruh Yigit
2024-03-12 18:06 ` [PATCH v4 04/31] net/ena: sub-optimal configuration notifications support shaibran
2024-03-12 18:06 ` [PATCH v4 05/31] net/ena: fix fast mbuf free shaibran
2024-03-13 15:58   ` Ferruh Yigit
2024-03-12 18:06 ` [PATCH v4 06/31] net/ena: restructure the llq policy setting process shaibran
2024-03-12 18:06 ` [PATCH v4 07/31] net/ena/base: limit exponential backoff exp shaibran
2024-03-13 15:58   ` Ferruh Yigit
2024-03-12 18:06 ` [PATCH v4 08/31] net/ena/base: add a new csum offload bit shaibran
2024-03-13 15:58   ` Ferruh Yigit
2024-03-12 18:06 ` [PATCH v4 09/31] net/ena/base: optimize Rx ring submission queue shaibran
2024-03-12 18:06 ` [PATCH v4 10/31] net/ena/base: rename fields in completion descriptors shaibran
2024-03-12 18:06 ` [PATCH v4 11/31] net/ena/base: use correct read once on u8 field shaibran
2024-03-12 18:06 ` [PATCH v4 12/31] net/ena/base: add completion descriptor corruption check shaibran
2024-03-12 18:06 ` [PATCH v4 13/31] net/ena/base: malformed Tx descriptor error reason shaibran
2024-03-13 15:58   ` Ferruh Yigit
2024-03-12 18:06 ` [PATCH v4 14/31] net/ena/base: phc feature modifications shaibran
2024-03-12 18:07 ` [PATCH v4 15/31] net/ena/base: restructure interrupt handling shaibran
2024-03-13 15:58   ` Ferruh Yigit
2024-03-12 18:07 ` [PATCH v4 16/31] net/ena/base: add unlikely to error checks shaibran
2024-03-12 18:07 ` [PATCH v4 17/31] net/ena/base: missing admin interrupt reset reason shaibran
2024-03-12 18:07 ` [PATCH v4 18/31] net/ena/base: check for existing keep alive notification shaibran
2024-03-12 18:07 ` shaibran [this message]
2024-03-12 18:07 ` [PATCH v4 20/31] net/ena/base: rework Rx ring submission queue shaibran
2024-03-12 18:07 ` [PATCH v4 21/31] net/ena/base: remove operating system type enum shaibran
2024-03-12 18:07 ` [PATCH v4 22/31] net/ena/base: handle command abort shaibran
2024-03-12 18:07 ` [PATCH v4 23/31] net/ena/base: add support for device reset request shaibran
2024-03-12 18:07 ` [PATCH v4 24/31] net/ena: cosmetic changes shaibran
2024-03-13 15:58   ` Ferruh Yigit
2024-03-12 18:07 ` [PATCH v4 25/31] net/ena/base: modify customer metrics memory management shaibran
2024-03-12 18:07 ` [PATCH v4 26/31] net/ena/base: modify logs to use unsigned format specifier shaibran
2024-03-12 18:07 ` [PATCH v4 27/31] net/ena: update device-preferred size of rings shaibran
2024-03-12 18:07 ` [PATCH v4 28/31] net/ena: exhaust interrupt callbacks in device close shaibran
2024-03-12 18:07 ` [PATCH v4 29/31] net/ena: support max large llq depth from the device shaibran
2024-03-12 18:07 ` [PATCH v4 30/31] net/ena: control path pure polling mode shaibran
2024-03-12 18:07 ` [PATCH v4 31/31] net/ena: upgrade driver version to 2.9.0 shaibran
2024-03-13 16:00 ` [PATCH v4 00/31] net/ena: v2.9.0 driver release Ferruh Yigit
2024-03-13 17:07   ` Brandes, Shai

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