From: Richard Weinberger Subject: Re: [PATCH] pipe_to_sendpage: Ensure that MSG_MORE is set if we set MSG_SENDPAGE_NOTLAST Date: Mon, 25 Nov 2013 08:42:16 +0100 Message-ID: <47783210.a9ocpbYofP@sandpuppy> References: <1385336527-27304-1-git-send-email-richard@nod.at> <1385342706.10637.125.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, shawnlandden@gmail.com, linux-crypto@vger.kernel.org, netdev@vger.kernel.org, herbert@gondor.apana.org.au, Tom Herbert , "David S. Miller" , stable@vger.kernel.org To: Eric Dumazet Return-path: In-Reply-To: <1385342706.10637.125.camel@edumazet-glaptop2.roam.corp.google.com> Sender: stable-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Am Sonntag, 24. November 2013, 17:25:06 schrieb Eric Dumazet: > On Mon, 2013-11-25 at 00:42 +0100, Richard Weinberger wrote: > > Commit 35f9c09fe (tcp: tcp_sendpages() should call tcp_push() once) > > added an internal flag MSG_SENDPAGE_NOTLAST. > > We have to ensure that MSG_MORE is also set if we set > > MSG_SENDPAGE_NOTLAST. > > Otherwise users that check against MSG_MORE will not see it. > > > > This fixes sendfile() on AF_ALG. > > > > Cc: Tom Herbert > > Cc: Eric Dumazet > > Cc: David S. Miller > > Cc: # 3.4.x > > Reported-and-tested-by: Shawn Landden > > Signed-off-by: Richard Weinberger > > --- > > > > fs/splice.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/splice.c b/fs/splice.c > > index 3b7ee65..b93f1b8 100644 > > --- a/fs/splice.c > > +++ b/fs/splice.c > > @@ -701,7 +701,7 @@ static int pipe_to_sendpage(struct pipe_inode_info > > *pipe,> > > more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; > > > > if (sd->len < sd->total_len && pipe->nrbufs > 1) > > > > - more |= MSG_SENDPAGE_NOTLAST; > > + more |= MSG_SENDPAGE_NOTLAST | MSG_MORE; > > > > return file->f_op->sendpage(file, buf->page, buf->offset, > > > > sd->len, &pos, more); > > I do not think this patch is right. It looks like a revert of a useful > patch for TCP zero copy. Given the time it took to discover this > regression, I bet tcp zero copy has more users than AF_ALG, by 5 or 6 > order of magnitude ;) Yeah, but AF_ALG broke. That's why I did the patch. > Here we want to make the difference between the two flags, not merge > them. > > If AF_ALG do not care of the difference, try instead : > > diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c > index ef5356cd280a..850246206b12 100644 > --- a/crypto/algif_hash.c > +++ b/crypto/algif_hash.c > @@ -114,6 +114,9 @@ static ssize_t hash_sendpage(struct socket *sock, struct > page *page, struct hash_ctx *ctx = ask->private; > int err; > > + if (flags & MSG_SENDPAGE_NOTLAST) > + flags |= MSG_MORE; > + In the commit message of your patch you wrote "For all sendpage() providers, its a transparent change.". Why does AF_ALG need special handling? If users have to care about MSG_SENDPAGE_NOTLAST it is no longer really an internal flag. Thanks, //richard