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author | Zoltan Kiss <zoltan.kiss@citrix.com> | 2014-07-18 19:08:02 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-28 08:08:26 -0700 |
commit | f6526b2a7f32c894d55e27d31f4c47396b93be2d (patch) | |
tree | 1b630ab16ca2374ec79fdf7746649c4ab69984d0 /drivers | |
parent | 9b78a74623c7789c6b6d3abe4b802fa8cb7d1946 (diff) | |
download | lwn-f6526b2a7f32c894d55e27d31f4c47396b93be2d.tar.gz lwn-f6526b2a7f32c894d55e27d31f4c47396b93be2d.zip |
xen-netback: Fix handling frag_list on grant op error path
[ Upstream commit 1a998d3e6bc1e44f4c0bc7509bdedef8ed3845ec ]
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: Zoltan Kiss <zoltan.kiss@citrix.com>
Reported-by: Armin 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: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/net/xen-netback/netback.c | 37 |
1 files changed, 20 insertions, 17 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 7367208ee8cd..9b0f482fc8d0 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1007,10 +1007,16 @@ static int xenvif_tx_check_gop(struct xenvif *vif, { 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; @@ -1063,31 +1069,28 @@ check_frags: xenvif_idx_unmap(vif, 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(vif, 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(vif, pending_idx); - } - } - *gopp_map = gop_map; return err; } |