Commit 7c1c3eb8 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block

* 'splice' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] splice: make the read-side do batched page lookups
  [PATCH] Add find_get_pages_contig(): contiguous variant of find_get_pages()
  [PATCH] splice: switch to using page_cache_readahead()
parents 6e5882cf eb20796b
......@@ -279,7 +279,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
pgoff_t index, end_index;
loff_t isize;
size_t total_len;
int error;
int error, page_nr;
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
......@@ -299,32 +299,34 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
* read-ahead if this is a non-zero offset (we are likely doing small
* chunk splice and the page is already there) for a single page.
*/
if (!loff || spd.nr_pages > 1)
do_page_cache_readahead(mapping, in, index, spd.nr_pages);
if (!loff || nr_pages > 1)
page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
/*
* Now fill in the holes:
*/
error = 0;
total_len = 0;
for (spd.nr_pages = 0; spd.nr_pages < nr_pages; spd.nr_pages++, index++) {
unsigned int this_len;
if (!len)
break;
/*
* Lookup the (hopefully) full range of pages we need.
*/
spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages);
/*
* this_len is the max we'll use from this page
* If find_get_pages_contig() returned fewer pages than we needed,
* allocate the rest.
*/
this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
find_page:
index += spd.nr_pages;
while (spd.nr_pages < nr_pages) {
/*
* lookup the page for this index
* Page could be there, find_get_pages_contig() breaks on
* the first hole.
*/
page = find_get_page(mapping, index);
if (!page) {
/*
* page didn't exist, allocate one
* page didn't exist, allocate one.
*/
page = page_cache_alloc_cold(mapping);
if (!page)
......@@ -336,10 +338,36 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
page_cache_release(page);
break;
}
/*
* add_to_page_cache() locks the page, unlock it
* to avoid convoluting the logic below even more.
*/
unlock_page(page);
}
goto readpage;
pages[spd.nr_pages++] = page;
index++;
}
/*
* Now loop over the map and see if we need to start IO on any
* pages, fill in the partial map, etc.
*/
index = *ppos >> PAGE_CACHE_SHIFT;
nr_pages = spd.nr_pages;
spd.nr_pages = 0;
for (page_nr = 0; page_nr < nr_pages; page_nr++) {
unsigned int this_len;
if (!len)
break;
/*
* this_len is the max we'll use from this page
*/
this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
page = pages[page_nr];
/*
* If the page isn't uptodate, we may need to start io on it
*/
......@@ -360,7 +388,6 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
*/
if (!page->mapping) {
unlock_page(page);
page_cache_release(page);
break;
}
/*
......@@ -371,16 +398,20 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
goto fill_it;
}
readpage:
/*
* need to read in the page
*/
error = mapping->a_ops->readpage(in, page);
if (unlikely(error)) {
page_cache_release(page);
/*
* We really should re-lookup the page here,
* but it complicates things a lot. Instead
* lets just do what we already stored, and
* we'll get it the next time we are called.
*/
if (error == AOP_TRUNCATED_PAGE)
goto find_page;
error = 0;
break;
}
......@@ -389,10 +420,8 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
*/
isize = i_size_read(mapping->host);
end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
if (unlikely(!isize || index > end_index)) {
page_cache_release(page);
if (unlikely(!isize || index > end_index))
break;
}
/*
* if this is the last page, see if we need to shrink
......@@ -400,27 +429,33 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
*/
if (end_index == index) {
loff = PAGE_CACHE_SIZE - (isize & ~PAGE_CACHE_MASK);
if (total_len + loff > isize) {
page_cache_release(page);
if (total_len + loff > isize)
break;
}
/*
* force quit after adding this page
*/
nr_pages = spd.nr_pages;
len = this_len;
this_len = min(this_len, loff);
loff = 0;
}
}
fill_it:
pages[spd.nr_pages] = page;
partial[spd.nr_pages].offset = loff;
partial[spd.nr_pages].len = this_len;
partial[page_nr].offset = loff;
partial[page_nr].len = this_len;
len -= this_len;
total_len += this_len;
loff = 0;
spd.nr_pages++;
index++;
}
/*
* Release any pages at the end, if we quit early. 'i' is how far
* we got, 'nr_pages' is how many pages are in the map.
*/
while (page_nr < nr_pages)
page_cache_release(pages[page_nr++]);
if (spd.nr_pages)
return splice_to_pipe(pipe, &spd);
......
......@@ -78,6 +78,8 @@ extern struct page * find_or_create_page(struct address_space *mapping,
unsigned long index, gfp_t gfp_mask);
unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
int tag, unsigned int nr_pages, struct page **pages);
......
......@@ -697,6 +697,38 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
return ret;
}
/**
* find_get_pages_contig - gang contiguous pagecache lookup
* @mapping: The address_space to search
* @index: The starting page index
* @nr_pages: The maximum number of pages
* @pages: Where the resulting pages are placed
*
* find_get_pages_contig() works exactly like find_get_pages(), except
* that the returned number of pages are guaranteed to be contiguous.
*
* find_get_pages_contig() returns the number of pages which were found.
*/
unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
unsigned int nr_pages, struct page **pages)
{
unsigned int i;
unsigned int ret;
read_lock_irq(&mapping->tree_lock);
ret = radix_tree_gang_lookup(&mapping->page_tree,
(void **)pages, index, nr_pages);
for (i = 0; i < ret; i++) {
if (pages[i]->mapping == NULL || pages[i]->index != index)
break;
page_cache_get(pages[i]);
index++;
}
read_unlock_irq(&mapping->tree_lock);
return i;
}
/*
* Like find_get_pages, except we only return pages which are tagged with
* `tag'. We update *index to index the next page for the traversal.
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment