Patchwork [v2,3/4] xen/netback: free already allocated memory on failure in xen_netbk_get_requests

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Submitter Ian Campbell
Date Feb. 7, 2013, 9:41 a.m.
Message ID <1360230098-28218-3-git-send-email-ian.campbell@citrix.com>
Download mbox | patch
Permalink /patch/218870/
State Accepted
Delegated to: David Miller
Headers show

Comments

Ian Campbell - Feb. 7, 2013, 9:41 a.m.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: <stable@vger.kernel.org> # 3.0+
---
v2: s/reponses/responses/ (blp) & fixup block comment style (DaveM)
---
 drivers/net/xen-netback/netback.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

Patch

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index bf692df..dcb2d4d 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -978,7 +978,7 @@  static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
 		pending_idx = netbk->pending_ring[index];
 		page = xen_netbk_alloc_page(netbk, skb, pending_idx);
 		if (!page)
-			return NULL;
+			goto err;
 
 		gop->source.u.ref = txp->gref;
 		gop->source.domid = vif->domid;
@@ -1000,6 +1000,17 @@  static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
 	}
 
 	return gop;
+err:
+	/* Unwind, freeing all pages and sending error responses. */
+	while (i-- > start) {
+		xen_netbk_idx_release(netbk, frag_get_pending_idx(&frags[i]),
+				      XEN_NETIF_RSP_ERROR);
+	}
+	/* The head too, if necessary. */
+	if (start)
+		xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+
+	return NULL;
 }
 
 static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,