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FAILED: patch "[PATCH] sfc: The RX page_ring is optional" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Jan 7, 2022

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Network drivers Stable branch Sfc network driver
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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1d5a474240407c38ca8c7484a656ee39f585399c Mon Sep 17 00:00:00 2001
From: Martin Habets <[email protected]>
Date: Sun, 2 Jan 2022 08:41:22 +0000
Subject: [PATCH] sfc: The RX page_ring is optional

The RX page_ring is an optional feature that improves performance. When allocation fails the driver can still function, but possibly with a lower bandwidth. Guard against dereferencing a NULL page_ring.

Fixes 2768935a4660 ("sfc: reuse pages to avoid DMA mapping/unmapping costs")
Signed-off-by Martin Habets <[email protected]>
Reported-by Jiasheng Jiang <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Jakub Kicinski <[email protected]>
drivers/net/ethernet/sfc/falcon/rx.c +5 -0
index 11a6aee852e9..0c6cc2191369 100644
@@ -110,6 +110,8 @@ static struct page *ef4_reuse_page(struct ef4_rx_queue *rx_queue)
 	struct ef4_rx_page_state *state;
 	unsigned index;
 
+	if (unlikely(!rx_queue->page_ring))
+		return NULL;
 	index = rx_queue->page_remove & rx_queue->page_ptr_mask;
 	page = rx_queue->page_ring[index];
 	if (page == NULL)

@@ -293,6 +295,9 @@ static void ef4_recycle_rx_pages(struct ef4_channel *channel,
 {
 	struct ef4_rx_queue *rx_queue = ef4_channel_get_rx_queue(channel);
 
+	if (unlikely(!rx_queue->page_ring))
+		return;
+
 	do {
 		ef4_recycle_rx_page(channel, rx_buf);
 		rx_buf = ef4_rx_buf_next(rx_queue, rx_buf);
drivers/net/ethernet/sfc/rx_common.c +5 -0
index 0983abc0cc5f..633ca77a26fd 100644
@@ -45,6 +45,8 @@ static struct page *efx_reuse_page(struct efx_rx_queue *rx_queue)
 	unsigned int index;
 	struct page *page;
 
+	if (unlikely(!rx_queue->page_ring))
+		return NULL;
 	index = rx_queue->page_remove & rx_queue->page_ptr_mask;
 	page = rx_queue->page_ring[index];
 	if (page == NULL)

@@ -114,6 +116,9 @@ void efx_recycle_rx_pages(struct efx_channel *channel,
 {
 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
 
+	if (unlikely(!rx_queue->page_ring))
+		return;
+
 	do {
 		efx_recycle_rx_page(channel, rx_buf);
 		rx_buf = efx_rx_buf_next(rx_queue, rx_buf);