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| author | Jens Axboe <jens.axboe@oracle.com> | 2010-05-20 10:43:18 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2010-05-21 21:12:40 +0200 |
| commit | 35f3d14dbbc58447c61e38a162ea10add6b31dc7 (patch) | |
| tree | 3e03cd540b7dcdac82195c4e76862c0ce6daaaf0 /kernel/relay.c | |
| parent | 3d42b3612891baecf709d93f28655a6882a65d41 (diff) | |
| download | linux-rt-35f3d14dbbc58447c61e38a162ea10add6b31dc7.tar.gz | |
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 <jens.axboe@oracle.com>
Diffstat (limited to 'kernel/relay.c')
| -rw-r--r-- | kernel/relay.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/relay.c b/kernel/relay.c index 3d97f2821611..4268287148c1 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -1231,8 +1231,8 @@ static ssize_t subbuf_splice_actor(struct file *in, size_t read_subbuf = read_start / subbuf_size; size_t padding = rbuf->padding[read_subbuf]; size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding; - struct page *pages[PIPE_BUFFERS]; - struct partial_page partial[PIPE_BUFFERS]; + struct page *pages[PIPE_DEF_BUFFERS]; + struct partial_page partial[PIPE_DEF_BUFFERS]; struct splice_pipe_desc spd = { .pages = pages, .nr_pages = 0, @@ -1245,6 +1245,8 @@ static ssize_t subbuf_splice_actor(struct file *in, if (rbuf->subbufs_produced == rbuf->subbufs_consumed) return 0; + if (splice_grow_spd(pipe, &spd)) + return -ENOMEM; /* * Adjust read len, if longer than what is available @@ -1255,7 +1257,7 @@ static ssize_t subbuf_splice_actor(struct file *in, subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT; pidx = (read_start / PAGE_SIZE) % subbuf_pages; poff = read_start & ~PAGE_MASK; - nr_pages = min_t(unsigned int, subbuf_pages, PIPE_BUFFERS); + nr_pages = min_t(unsigned int, subbuf_pages, pipe->buffers); for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) { unsigned int this_len, this_end, private; @@ -1289,16 +1291,19 @@ static ssize_t subbuf_splice_actor(struct file *in, } } + ret = 0; if (!spd.nr_pages) - return 0; + goto out; ret = *nonpad_ret = splice_to_pipe(pipe, &spd); if (ret < 0 || ret < total_len) - return ret; + goto out; if (read_start + ret == nonpad_end) ret += padding; +out: + splice_shrink_spd(pipe, &spd); return ret; } |