[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 <axboe@suse.de>
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parent
16c523ddab
commit
49d0b21be2
1 changed files with 31 additions and 11 deletions
42
fs/splice.c
42
fs/splice.c
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@ -84,26 +84,43 @@ static void *page_cache_pipe_buf_map(struct file *file,
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struct pipe_buffer *buf)
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{
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struct page *page = buf->page;
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lock_page(page);
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int err;
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if (!PageUptodate(page)) {
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lock_page(page);
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/*
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* Page got truncated/unhashed. This will cause a 0-byte
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* splice, if this is the first page
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*/
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if (!page->mapping) {
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err = -ENODATA;
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goto error;
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}
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/*
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* uh oh, read-error from disk
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*/
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if (!PageUptodate(page)) {
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err = -EIO;
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goto error;
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}
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/*
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* page is ok afterall, fall through to mapping
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*/
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unlock_page(page);
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return ERR_PTR(-EIO);
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}
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if (!page->mapping) {
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unlock_page(page);
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return ERR_PTR(-ENODATA);
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}
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return kmap(buf->page);
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return kmap(page);
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error:
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unlock_page(page);
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return ERR_PTR(err);
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}
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static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
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struct pipe_buffer *buf)
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{
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unlock_page(buf->page);
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kunmap(buf->page);
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}
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@ -379,7 +396,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
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int ret;
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/*
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* after this, page will be locked and unmapped
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* make sure the data in this buffer is uptodate
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*/
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src = buf->ops->map(file, info, buf);
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if (IS_ERR(src))
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@ -399,6 +416,9 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
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if (buf->ops->steal(info, buf))
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goto find_page;
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/*
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* this will also set the page locked
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*/
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page = buf->page;
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if (add_to_page_cache(page, mapping, index, gfp_mask))
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goto find_page;
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