[ 29/36] xen/netback: free already allocated memory on failure in xen_netbk_get_requests

Greg Kroah-Hartman
2013-02-12T20:42:00Z

From: Ian Campbell <Ian.Campbell@citrix.com>

[ Upstream commit 4cc7c1cb7b11b6f3515bd9075527576a1eecc4aa ]

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/xen-netback/netback.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -950,7 +950,7 @@ static struct gnttab_copy *xen_netbk_get
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;
@@ -972,6 +972,17 @@ static struct gnttab_copy *xen_netbk_get
}

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,