From f84d751994441292593523c7069ed147176f6cab Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 1 May 2006 19:59:03 +0200 Subject: [PATCH] pipe: introduce ->pin() buffer operation The ->map() function is really expensive on highmem machines right now, since it has to use the slower kmap() instead of kmap_atomic(). Splice rarely needs to access the virtual address of a page, so it's a waste of time doing it. Introduce ->pin() to take over the responsibility of making sure the page data is valid. ->map() is then reduced to just kmap(). That way we can also share a most of the pipe buffer ops between pipe.c and splice.c Signed-off-by: Jens Axboe --- fs/pipe.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) (limited to 'fs/pipe.c') diff --git a/fs/pipe.c b/fs/pipe.c index 888f265011b..d9644fd9cc0 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -110,14 +110,14 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe, page_cache_release(page); } -static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe, - struct pipe_buffer *buf) +void *generic_pipe_buf_map(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) { return kmap(buf->page); } -static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe, - struct pipe_buffer *buf) +void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) { kunmap(buf->page); } @@ -135,19 +135,24 @@ static int anon_pipe_buf_steal(struct pipe_inode_info *pipe, return 1; } -static void anon_pipe_buf_get(struct pipe_inode_info *info, - struct pipe_buffer *buf) +void generic_pipe_buf_get(struct pipe_inode_info *info, struct pipe_buffer *buf) { page_cache_get(buf->page); } +int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf) +{ + return 0; +} + static struct pipe_buf_operations anon_pipe_buf_ops = { .can_merge = 1, - .map = anon_pipe_buf_map, - .unmap = anon_pipe_buf_unmap, + .map = generic_pipe_buf_map, + .unmap = generic_pipe_buf_unmap, + .pin = generic_pipe_buf_pin, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, - .get = anon_pipe_buf_get, + .get = generic_pipe_buf_get, }; static ssize_t @@ -183,12 +188,14 @@ pipe_readv(struct file *filp, const struct iovec *_iov, if (chars > total_len) chars = total_len; - addr = ops->map(filp, pipe, buf); - if (IS_ERR(addr)) { + error = ops->pin(pipe, buf); + if (error) { if (!ret) - ret = PTR_ERR(addr); + error = ret; break; } + + addr = ops->map(pipe, buf); error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); ops->unmap(pipe, buf); if (unlikely(error)) { @@ -300,11 +307,11 @@ pipe_writev(struct file *filp, const struct iovec *_iov, void *addr; int error; - addr = ops->map(filp, pipe, buf); - if (IS_ERR(addr)) { - error = PTR_ERR(addr); + error = ops->pin(pipe, buf); + if (error) goto out; - } + + addr = ops->map(pipe, buf); error = pipe_iov_copy_from_user(offset + addr, iov, chars); ops->unmap(pipe, buf); -- cgit v1.2.3