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Commit 1a998d3e authored by Zoltan Kiss's avatar Zoltan Kiss Committed by David S. Miller
Browse files

xen-netback: Fix handling frag_list on grant op error path 



The error handling for skb's with frag_list was completely wrong, it caused
double unmap attempts to happen if the error was on the first skb. Move it to
the right place in the loop.

Signed-off-by: default avatarZoltan Kiss <zoltan.kiss@citrix.com>
Reported-by: default avatarArmin Zentai <armin.zentai@ezit.hu>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7801db8a

drivers/net/xen-netback/netback.c

+20 −17
Original line number Diff line number Diff line
@@ -1030,10 +1030,16 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue, 
{

	struct gnttab_map_grant_ref *gop_map = *gopp_map;

	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;

	/* This always points to the shinfo of the skb being checked, which

	 * could be either the first or the one on the frag_list

	 */

	struct skb_shared_info *shinfo = skb_shinfo(skb);

	/* If this is non-NULL, we are currently checking the frag_list skb, and

	 * this points to the shinfo of the first one

	 */

	struct skb_shared_info *first_shinfo = NULL;

	int nr_frags = shinfo->nr_frags;

	int i, err;

	struct sk_buff *first_skb = NULL;



	/* Check status of header. */

	err = (*gopp_copy)->status;
@@ -1086,31 +1092,28 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue, 
			xenvif_idx_unmap(queue, pending_idx);

		}



		/* And if we found the error while checking the frag_list, unmap

		 * the first skb's frags

		 */

		if (first_shinfo) {

			for (j = 0; j < first_shinfo->nr_frags; j++) {

				pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);

				xenvif_idx_unmap(queue, pending_idx);

			}

		}



		/* Remember the error: invalidate all subsequent fragments. */

		err = newerr;

	}



	if (skb_has_frag_list(skb)) {

		first_skb = skb;

		skb = shinfo->frag_list;

		shinfo = skb_shinfo(skb);

	if (skb_has_frag_list(skb) && !first_shinfo) {

		first_shinfo = skb_shinfo(skb);

		shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);

		nr_frags = shinfo->nr_frags;



		goto check_frags;

	}



	/* There was a mapping error in the frag_list skb. We have to unmap

	 * the first skb's frags

	 */

	if (first_skb && err) {

		int j;

		shinfo = skb_shinfo(first_skb);

		for (j = 0; j < shinfo->nr_frags; j++) {

			pending_idx = frag_get_pending_idx(&shinfo->frags[j]);

			xenvif_idx_unmap(queue, pending_idx);

		}

	}



	*gopp_map = gop_map;

	return err;

}