Patch "sfc: Fix memory leak when discarding scattered packets" has been added to the 3.10-stable tree

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

    sfc: Fix memory leak when discarding scattered packets

to the 3.10-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:
     sfc-fix-memory-leak-when-discarding-scattered-packets.patch
and it can be found in the queue-3.10 subdirectory.

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


>From 8db99edc36ca323408ba5c5bcb8952b01be50225 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
Date: Thu, 4 Jul 2013 23:48:46 +0100
Subject: sfc: Fix memory leak when discarding scattered packets

From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>

[ Upstream commit 734d4e159b283a4ae4d007b7e7a91d84398ccb92 ]

Commit 2768935a4660 ('sfc: reuse pages to avoid DMA mapping/unmapping
costs') did not fully take account of DMA scattering which was
introduced immediately before.  If a received packet is invalid and
must be discarded, we only drop a reference to the first buffer's
page, but we need to drop a reference for each buffer the packet
used.

I think this bug was missed partly because efx_recycle_rx_buffers()
was not renamed and so no longer does what its name says.  It does not
change the state of buffers, but only prepares the underlying pages
for recycling.  Rename it accordingly.

Signed-off-by: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/sfc/rx.c |   27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -282,9 +282,9 @@ static void efx_fini_rx_buffer(struct ef
 }
 
 /* Recycle the pages that are used by buffers that have just been received. */
-static void efx_recycle_rx_buffers(struct efx_channel *channel,
-				   struct efx_rx_buffer *rx_buf,
-				   unsigned int n_frags)
+static void efx_recycle_rx_pages(struct efx_channel *channel,
+				 struct efx_rx_buffer *rx_buf,
+				 unsigned int n_frags)
 {
 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
 
@@ -294,6 +294,20 @@ static void efx_recycle_rx_buffers(struc
 	} while (--n_frags);
 }
 
+static void efx_discard_rx_packet(struct efx_channel *channel,
+				  struct efx_rx_buffer *rx_buf,
+				  unsigned int n_frags)
+{
+	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
+
+	efx_recycle_rx_pages(channel, rx_buf, n_frags);
+
+	do {
+		efx_free_rx_buffer(rx_buf);
+		rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
+	} while (--n_frags);
+}
+
 /**
  * efx_fast_push_rx_descriptors - push new RX descriptors quickly
  * @rx_queue:		RX descriptor queue
@@ -533,8 +547,7 @@ void efx_rx_packet(struct efx_rx_queue *
 	 */
 	if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
 		efx_rx_flush_packet(channel);
-		put_page(rx_buf->page);
-		efx_recycle_rx_buffers(channel, rx_buf, n_frags);
+		efx_discard_rx_packet(channel, rx_buf, n_frags);
 		return;
 	}
 
@@ -570,9 +583,9 @@ void efx_rx_packet(struct efx_rx_queue *
 		efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 	}
 
-	/* All fragments have been DMA-synced, so recycle buffers and pages. */
+	/* All fragments have been DMA-synced, so recycle pages. */
 	rx_buf = efx_rx_buffer(rx_queue, index);
-	efx_recycle_rx_buffers(channel, rx_buf, n_frags);
+	efx_recycle_rx_pages(channel, rx_buf, n_frags);
 
 	/* Pipeline receives so that we give time for packet headers to be
 	 * prefetched into cache.


Patches currently in stable-queue which might be from bhutchings@xxxxxxxxxxxxxx are

queue-3.10/sfc-fix-memory-leak-when-discarding-scattered-packets.patch
queue-3.10/atl1e-unmap-partially-mapped-skb-on-dma-error-and-free-skb.patch
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