This is a note to let you know that I've just added the patch titled
net: macb: Increment rx bd head after allocating skb and buffer
to the 5.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-macb-increment-rx-bd-head-after-allocating-skb-a.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5d75c47d7a8d39457c7a9046ed17eaefb8b676c5
Author: Harini Katakam <harini.katakam@xxxxxxxxxx>
Date: Thu May 12 22:49:00 2022 +0530
net: macb: Increment rx bd head after allocating skb and buffer
[ Upstream commit 9500acc631dbb8b73166e25700e656b11f6007b6 ]
In gem_rx_refill rx_prepared_head is incremented at the beginning of
the while loop preparing the skb and data buffers. If the skb or data
buffer allocation fails, this BD will be unusable BDs until the head
loops back to the same BD (and obviously buffer allocation succeeds).
In the unlikely event that there's a string of allocation failures,
there will be an equal number of unusable BDs and an inconsistent RX
BD chain. Hence increment the head at the end of the while loop to be
clean.
Fixes: 4df95131ea80 ("net/macb: change RX path for GEM")
Signed-off-by: Harini Katakam <harini.katakam@xxxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>
Reviewed-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220512171900.32593-1-harini.katakam@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index c4f4b13ac469..c1100af5666b 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -1217,7 +1217,6 @@ static void gem_rx_refill(struct macb_queue *queue)
/* Make hw descriptor updates visible to CPU */
rmb();
- queue->rx_prepared_head++;
desc = macb_rx_desc(queue, entry);
if (!queue->rx_skbuff[entry]) {
@@ -1256,6 +1255,7 @@ static void gem_rx_refill(struct macb_queue *queue)
dma_wmb();
desc->addr &= ~MACB_BIT(RX_USED);
}
+ queue->rx_prepared_head++;
}
/* Make descriptor updates visible to hardware */
