Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966118Ab2EORe2 (ORCPT ); Tue, 15 May 2012 13:34:28 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:41713 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966038Ab2EORe0 (ORCPT ); Tue, 15 May 2012 13:34:26 -0400 Subject: Re: [V2 PATCH 3/9] macvtap: zerocopy: put page when fail to get all requested user pages From: Shirley Ma To: Jason Wang Cc: eric.dumazet@gmail.com, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ebiederm@xmission.com, davem@davemloft.net In-Reply-To: <20120502034157.11782.66606.stgit@amd-6168-8-1.englab.nay.redhat.com> References: <20120502033901.11782.13157.stgit@amd-6168-8-1.englab.nay.redhat.com> <20120502034157.11782.66606.stgit@amd-6168-8-1.englab.nay.redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 15 May 2012 10:33:56 -0700 Message-ID: <1337103236.8220.13.camel@oc3660625478.ibm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 (2.28.3-24.el6) Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12051517-6078-0000-0000-00000B0AE0B9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1785 Lines: 47 On Wed, 2012-05-02 at 11:41 +0800, Jason Wang wrote: > When get_user_pages_fast() fails to get all requested pages, we could > not use > kfree_skb() to free it as it has not been put in the skb fragments. So > we need > to call put_page() instead. > > Signed-off-by: Jason Wang > --- > drivers/net/macvtap.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index 7cb2684..9ab182a 100644 > --- a/drivers/net/macvtap.c > +++ b/drivers/net/macvtap.c > @@ -531,9 +531,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff > *skb, const struct iovec *from, > size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> > PAGE_SHIFT; > num_pages = get_user_pages_fast(base, size, 0, > &page[i]); > if ((num_pages != size) || > - (num_pages > MAX_SKB_FRAGS - > skb_shinfo(skb)->nr_frags)) > - /* put_page is in skb free */ > + (num_pages > MAX_SKB_FRAGS - > skb_shinfo(skb)->nr_frags)) { > + for (i = 0; i < num_pages; i++) > + put_page(page[i]); > return -EFAULT; > + } > truesize = size * PAGE_SIZE; > skb->data_len += len; > skb->len += len; Good catch. I don't know why I thought put_page would be called in skb_free for these pages which hadn't been added to skb frags before. :( thanks Shirley -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/