[PATCH 5/6] net/core: support compiling out splice
From: Pieter Smith <hidden>
Date: 2014-11-23 14:20:49
Also in:
linux-api, linux-fsdevel, lkml
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2014-11-22 · Re: [PATCH 5/6] net/core: support compiling out splice · Josh Triplett <josh@joshtriplett.org>
- 2014-11-22 · Re: [PATCH 5/6] net/core: support compiling out splice · Josh Triplett <josh@joshtriplett.org>
- 2014-11-22 · [PATCH 5/6] net/core: support compiling out splice · Pieter Smith <hidden>
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 <redacted> --- include/linux/skbuff.h | 9 +++++++++ net/core/skbuff.c | 9 ++++++--- 2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a59d934..54a50c1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -2640,9 +2640,18 @@ 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..74fad8a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -1781,9 +1781,9 @@ 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 +1821,7 @@ 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 +1877,8 @@ done: return ret; } +#endif /* #ifdef CONFIG_SYSCALL_SPLICE */ + /** * skb_store_bits - store bits from kernel buffer to skb
--
2.1.0
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