From: Jens Axboe Date: Mon, 10 Apr 2006 07:04:41 +0000 (+0200) Subject: [PATCH] splice: optimize the splice buffer mapping X-Git-Tag: MMI-PSA29.97-13-9~50194^2~15 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=49d0b21be21efc07526d637e0ae935019667e532;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git [PATCH] splice: optimize the splice buffer mapping We don't really need to lock down the pages, just make sure they are uptodate. Signed-off-by: Jens Axboe --- diff --git a/fs/splice.c b/fs/splice.c index 8b5efcc906dc..50c43a1e0923 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -84,26 +84,43 @@ static void *page_cache_pipe_buf_map(struct file *file, struct pipe_buffer *buf) { struct page *page = buf->page; - - lock_page(page); + int err; if (!PageUptodate(page)) { - unlock_page(page); - return ERR_PTR(-EIO); - } + lock_page(page); + + /* + * Page got truncated/unhashed. This will cause a 0-byte + * splice, if this is the first page + */ + if (!page->mapping) { + err = -ENODATA; + goto error; + } + + /* + * uh oh, read-error from disk + */ + if (!PageUptodate(page)) { + err = -EIO; + goto error; + } - if (!page->mapping) { + /* + * page is ok afterall, fall through to mapping + */ unlock_page(page); - return ERR_PTR(-ENODATA); } - return kmap(buf->page); + return kmap(page); +error: + unlock_page(page); + return ERR_PTR(err); } static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf) { - unlock_page(buf->page); kunmap(buf->page); } @@ -379,7 +396,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, int ret; /* - * after this, page will be locked and unmapped + * make sure the data in this buffer is uptodate */ src = buf->ops->map(file, info, buf); if (IS_ERR(src)) @@ -399,6 +416,9 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, if (buf->ops->steal(info, buf)) goto find_page; + /* + * this will also set the page locked + */ page = buf->page; if (add_to_page_cache(page, mapping, index, gfp_mask)) goto find_page;