From 35f3d14dbbc58447c61e38a162ea10add6b31dc7 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 20 May 2010 10:43:18 +0200 Subject: pipe: add support for shrinking and growing pipes This patch adds F_GETPIPE_SZ and F_SETPIPE_SZ fcntl() actions for growing and shrinking the size of a pipe and adjusts pipe.c and splice.c (and relay and network splice) usage to work with these larger (or smaller) pipes. Signed-off-by: Jens Axboe --- net/core/skbuff.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) (limited to 'net/core/skbuff.c') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 93c4e060c91..931981774b1 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1417,12 +1417,13 @@ new_page: /* * Fill page/offset/length into spd, if it can hold more pages. */ -static inline int spd_fill_page(struct splice_pipe_desc *spd, struct page *page, +static inline int spd_fill_page(struct splice_pipe_desc *spd, + struct pipe_inode_info *pipe, struct page *page, unsigned int *len, unsigned int offset, struct sk_buff *skb, int linear, struct sock *sk) { - if (unlikely(spd->nr_pages == PIPE_BUFFERS)) + if (unlikely(spd->nr_pages == pipe->buffers)) return 1; if (linear) { @@ -1458,7 +1459,8 @@ static inline int __splice_segment(struct page *page, unsigned int poff, unsigned int plen, unsigned int *off, unsigned int *len, struct sk_buff *skb, struct splice_pipe_desc *spd, int linear, - struct sock *sk) + struct sock *sk, + struct pipe_inode_info *pipe) { if (!*len) return 1; @@ -1481,7 +1483,7 @@ static inline int __splice_segment(struct page *page, unsigned int poff, /* the linear region may spread across several pages */ flen = min_t(unsigned int, flen, PAGE_SIZE - poff); - if (spd_fill_page(spd, page, &flen, poff, skb, linear, sk)) + if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk)) return 1; __segment_seek(&page, &poff, &plen, flen); @@ -1496,9 +1498,9 @@ static inline int __splice_segment(struct page *page, unsigned int poff, * Map linear and fragment data from the skb to spd. It reports failure if the * pipe is full or if we already spliced the requested length. */ -static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, - unsigned int *len, struct splice_pipe_desc *spd, - struct sock *sk) +static int __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; @@ -1508,7 +1510,7 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, if (__splice_segment(virt_to_page(skb->data), (unsigned long) skb->data & (PAGE_SIZE - 1), skb_headlen(skb), - offset, len, skb, spd, 1, sk)) + offset, len, skb, spd, 1, sk, pipe)) return 1; /* @@ -1518,7 +1520,7 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, const skb_frag_t *f = &skb_shinfo(skb)->frags[seg]; if (__splice_segment(f->page, f->page_offset, f->size, - offset, len, skb, spd, 0, sk)) + offset, len, skb, spd, 0, sk, pipe)) return 1; } @@ -1535,8 +1537,8 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset, struct pipe_inode_info *pipe, unsigned int tlen, unsigned int flags) { - struct partial_page partial[PIPE_BUFFERS]; - struct page *pages[PIPE_BUFFERS]; + struct partial_page partial[PIPE_DEF_BUFFERS]; + struct page *pages[PIPE_DEF_BUFFERS]; struct splice_pipe_desc spd = { .pages = pages, .partial = partial, @@ -1546,12 +1548,16 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset, }; struct sk_buff *frag_iter; struct sock *sk = skb->sk; + int ret = 0; + + if (splice_grow_spd(pipe, &spd)) + return -ENOMEM; /* * __skb_splice_bits() only fails if the output has no room left, * so no point in going over the frag_list for the error case. */ - if (__skb_splice_bits(skb, &offset, &tlen, &spd, sk)) + if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk)) goto done; else if (!tlen) goto done; @@ -1562,14 +1568,12 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset, skb_walk_frags(skb, frag_iter) { if (!tlen) break; - if (__skb_splice_bits(frag_iter, &offset, &tlen, &spd, sk)) + if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk)) break; } done: if (spd.nr_pages) { - int ret; - /* * Drop the socket lock, otherwise we have reverse * locking dependencies between sk_lock and i_mutex @@ -1582,10 +1586,10 @@ done: release_sock(sk); ret = splice_to_pipe(pipe, &spd); lock_sock(sk); - return ret; } - return 0; + splice_shrink_spd(pipe, &spd); + return ret; } /** -- cgit v1.2.3-18-g5258