[ 28/36] xen/netback: dont leak pages on failure in xen_netbk_tx_check_gop.

Greg Kroah-Hartman
2013-02-12T20:45:14Z

From: Matthew Daley <mattjd@gmail.com>

[ Upstream commit 7d5145d8eb2b9791533ffe4dc003b129b9696c48 ]

Signed-off-by: Matthew Daley <mattjd@gmail.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Jan Beulich <JBeulich@suse.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 | 38 +++++++++++++-------------------------
1 file changed, 13 insertions(+), 25 deletions(-)

--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -146,7 +146,8 @@ void xen_netbk_remove_xenvif(struct xenv
atomic_dec(&netbk->netfront_count);
}

-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
+static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
+ u8 status);
static void make_tx_response(struct xenvif *vif,
struct xen_netif_tx_request *txp,
s8 st);
@@ -979,30 +980,20 @@ static int xen_netbk_tx_check_gop(struct
{
struct gnttab_copy *gop = *gopp;
u16 pending_idx = *((u16 *)skb->data);
- struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
- struct xenvif *vif = pending_tx_info[pending_idx].vif;
- struct xen_netif_tx_request *txp;
struct skb_shared_info *shinfo = skb_shinfo(skb);
int nr_frags = shinfo->nr_frags;
int i, err, start;

/* Check status of header. */
err = gop->status;
- if (unlikely(err)) {
- pending_ring_idx_t index;
- index = pending_index(netbk->pending_prod++);
- txp = &pending_tx_info[pending_idx].req;
- make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
- netbk->pending_ring[index] = pending_idx;
- xenvif_put(vif);
- }
+ if (unlikely(err))
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);

/* Skip first skb fragment if it is on same page as header fragment. */
start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);

for (i = start; i < nr_frags; i++) {
int j, newerr;
- pending_ring_idx_t index;

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

@@ -1011,16 +1002,12 @@ static int xen_netbk_tx_check_gop(struct
if (likely(!newerr)) {
/* Had a previous error? Invalidate this fragment. */
if (unlikely(err))
- xen_netbk_idx_release(netbk, pending_idx);
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
continue;
}

/* Error on this fragment: respond to client with an error. */
- txp = &netbk->pending_tx_info[pending_idx].req;
- make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
- index = pending_index(netbk->pending_prod++);
- netbk->pending_ring[index] = pending_idx;
- xenvif_put(vif);
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);

/* Not the first error? Preceding frags already invalidated. */
if (err)
@@ -1028,10 +1015,10 @@ static int xen_netbk_tx_check_gop(struct

/* First error: invalidate header and preceding fragments. */
pending_idx = *((u16 *)skb->data);
- xen_netbk_idx_release(netbk, pending_idx);
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
for (j = start; j < i; j++) {
pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
- xen_netbk_idx_release(netbk, pending_idx);
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
}

/* Remember the error: invalidate all subsequent fragments. */
@@ -1065,7 +1052,7 @@ static void xen_netbk_fill_frags(struct

/* Take an extra reference to offset xen_netbk_idx_release */
get_page(netbk->mmap_pages[pending_idx]);
- xen_netbk_idx_release(netbk, pending_idx);
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
}
}

@@ -1448,7 +1435,7 @@ static void xen_netbk_tx_submit(struct x
txp->size -= data_len;
} else {
/* Schedule a response immediately. */
- xen_netbk_idx_release(netbk, pending_idx);
+ xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
}

if (txp->flags & XEN_NETTXF_csum_blank)
@@ -1503,7 +1490,8 @@ static void xen_netbk_tx_action(struct x

}

-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
+static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
+ u8 status)
{
struct xenvif *vif;
struct pending_tx_info *pending_tx_info;
@@ -1517,7 +1505,7 @@ static void xen_netbk_idx_release(struct

vif = pending_tx_info->vif;

- make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
+ make_tx_response(vif, &pending_tx_info->req, status);

index = pending_index(netbk->pending_prod++);
netbk->pending_ring[index] = pending_idx;