Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-wi0-f170.google.com ([209.85.212.170]:53453 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932544AbaLDRwT (ORCPT ); Thu, 4 Dec 2014 12:52:19 -0500 From: Pieter Smith To: linux-kernel@vger.kernel.org Cc: Josh Triplett , Pieter Smith , Alexander Duyck , Alexander Viro , Alexei Starovoitov , Andrew Morton , Bertrand Jacquin , Catalina Mocanu , Daniel Borkmann , "David S. Miller" , Eric Dumazet , "Eric W. Biederman" , Fabian Frederick , fuse-devel@lists.sourceforge.net (open list:FUSE: FILESYSTEM...), Geert Uytterhoeven , Hugh Dickins , Iulia Manda , Jan Beulich , "J. Bruce Fields" , Jeff Layton , linux-api@vger.kernel.org (open list:ABI/API), linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org (open list:KERNEL NFSD, SUNR...), "Luis R. Rodriguez" , Matt Turner , Mel Gorman , "Michael S. Tsirkin" , Miklos Szeredi , netdev@vger.kernel.org (open list:NETWORKING [GENERAL]), Oleg Nesterov , Paul Durrant , "Paul E. McKenney" , Peter Foley , Thomas Graf , Tom Herbert , Trond Myklebust , Willem de Bruijn , Xiao Guangrong , =?UTF-8?q?=E8=94=A1=E6=AD=A3=E9=BE=99?= Subject: [PATCH v6 5/7] net/core: support compiling out splice Date: Thu, 4 Dec 2014 18:50:53 +0100 Message-Id: <1417715473-24110-6-git-send-email-pieter@boesman.nl> In-Reply-To: <1417715473-24110-1-git-send-email-pieter@boesman.nl> References: <1417715473-24110-1-git-send-email-pieter@boesman.nl> Sender: linux-nfs-owner@vger.kernel.org List-ID: To implement splice support, net/core makes use of nosteal_pipe_buf_ops. This struct is exported by fs/splice. The goal of the larger patch set is to completely compile out fs/splice, so uses of the exported struct need to be compiled out along with fs/splice. This patch therefore compiles out splice support in net/core when CONFIG_SYSCALL_SPLICE is undefined. The compiled out function skb_splice_bits is transparently mocked out with a static inline. The greater patch set removes userspace splice support so it cannot be called anyway. Signed-off-by: Pieter Smith --- include/linux/skbuff.h | 10 ++++++++++ net/core/skbuff.c | 11 +++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index a59d934..5cd636b 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2640,9 +2640,19 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len); int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len); __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to, int len, __wsum csum); +#ifdef CONFIG_SYSCALL_SPLICE int skb_splice_bits(struct sk_buff *skb, unsigned int offset, struct pipe_inode_info *pipe, unsigned int len, unsigned int flags); +#else +static inline int +skb_splice_bits(struct sk_buff *skb, unsigned int offset, + struct pipe_inode_info *pipe, unsigned int len, + unsigned int flags) +{ + return -EPERM; +} +#endif void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to); unsigned int skb_zerocopy_headlen(const struct sk_buff *from); int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 61059a0..bb426d9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1678,7 +1678,8 @@ EXPORT_SYMBOL(skb_copy_bits); * Callback from splice_to_pipe(), if we need to release some pages * at the end of the spd in case we error'ed out in filling the pipe. */ -static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) +static void __maybe_unused sock_spd_release(struct splice_pipe_desc *spd, + unsigned int i) { put_page(spd->pages[i]); } @@ -1781,9 +1782,9 @@ static bool __splice_segment(struct page *page, unsigned int poff, * Map linear and fragment data from the skb to spd. It reports true if the * pipe is full or if we already spliced the requested length. */ -static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, - unsigned int *offset, unsigned int *len, - struct splice_pipe_desc *spd, struct sock *sk) +static bool __maybe_unused __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, + unsigned int *offset, unsigned int *len, + struct splice_pipe_desc *spd, struct sock *sk) { int seg; @@ -1821,6 +1822,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, * the frag list, if such a thing exists. We'd probably need to recurse to * handle that cleanly. */ +#ifdef CONFIG_SYSCALL_SPLICE int skb_splice_bits(struct sk_buff *skb, unsigned int offset, struct pipe_inode_info *pipe, unsigned int tlen, unsigned int flags) @@ -1876,6 +1878,7 @@ done: return ret; } +#endif /* CONFIG_SYSCALL_SPLICE */ /** * skb_store_bits - store bits from kernel buffer to skb -- 2.1.0