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[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>
This commit is contained in:
Jens Axboe 2006-04-10 09:04:41 +02:00
parent 16c523ddab
commit 49d0b21be2
1 changed files with 31 additions and 11 deletions
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42
fs/splice.c
View File

@ -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)) {
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;
}
/*
* page is ok afterall, fall through to mapping
*/
unlock_page(page);
return ERR_PTR(-EIO);
}
if (!page->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;