Patch "net/mlx5e: Do not recycle pages from emergency reserve" has been added to the 4.9-stable tree

Patch "net/mlx5e: Do not recycle pages from emergency reserve" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    net/mlx5e: Do not recycle pages from emergency reserve

to the 4.9-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-mlx5e-do-not-recycle-pages-from-emergency-reserve.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Feb  1 08:50:24 CET 2017
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 18 Jan 2017 23:03:08 -0800
Subject: net/mlx5e: Do not recycle pages from emergency reserve

From: Eric Dumazet <edumazet@google.com>


[ Upstream commit e048fc50d7bde23136e098e04a324d7e3404408d ]

A driver using dev_alloc_page() must not reuse a page allocated from
emergency memory reserve.

Otherwise all packets using this page will be immediately dropped,
unless for very specific sockets having SOCK_MEMALLOC bit set.

This issue might be hard to debug, because only a fraction of received
packets would be dropped.

Fixes: 4415a0319f92 ("net/mlx5e: Implement RX mapped page cache for page recycle")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -193,6 +193,9 @@ static inline bool mlx5e_rx_cache_put(st
 		return false;
 	}
 
+	if (unlikely(page_is_pfmemalloc(dma_info->page)))
+		return false;
+
 	cache->page_cache[cache->tail] = *dma_info;
 	cache->tail = tail_next;
 	return true;


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.9/mlx4-do-not-call-napi_schedule-without-care.patch
queue-4.9/net-mlx5e-do-not-recycle-pages-from-emergency-reserve.patch
queue-4.9/net-fix-harmonize_features-vs-netif_f_highdma.patch
queue-4.9/tcp-fix-tcp_fastopen-unaligned-access-complaints-on-sparc.patch
queue-4.9/tcp-initialize-max-window-for-a-new-fastopen-socket.patch