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CIFS: Separate page search from readpages 

Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Pavel Shilovsky 2014-06-24 13:08:54 +04:00 committed by Steve French
parent cb7e9eabb2
commit 387eb92ac6
1 changed files with 61 additions and 46 deletions
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107
fs/cifs/file.c
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@ -3340,6 +3340,63 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
return total_read > 0 && result != -EAGAIN ? total_read : result;
}
static int
readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
unsigned int rsize, struct list_head *tmplist,
unsigned int *nr_pages, loff_t *offset, unsigned int *bytes)
{
struct page *page, *tpage;
unsigned int expected_index;
int rc;
page = list_entry(page_list->prev, struct page, lru);
/*
* Lock the page and put it in the cache. Since no one else
* should have access to this page, we're safe to simply set
* PG_locked without checking it first.
*/
__set_page_locked(page);
rc = add_to_page_cache_locked(page, mapping,
page->index, GFP_KERNEL);
/* give up if we can't stick it in the cache */
if (rc) {
__clear_page_locked(page);
return rc;
}
/* move first page to the tmplist */
*offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
*bytes = PAGE_CACHE_SIZE;
*nr_pages = 1;
list_move_tail(&page->lru, tmplist);
/* now try and add more pages onto the request */
expected_index = page->index + 1;
list_for_each_entry_safe_reverse(page, tpage, page_list, lru) {
/* discontinuity ? */
if (page->index != expected_index)
break;
/* would this page push the read over the rsize? */
if (*bytes + PAGE_CACHE_SIZE > rsize)
break;
__set_page_locked(page);
if (add_to_page_cache_locked(page, mapping, page->index,
GFP_KERNEL)) {
__clear_page_locked(page);
break;
}
list_move_tail(&page->lru, tmplist);
(*bytes) += PAGE_CACHE_SIZE;
expected_index++;
(*nr_pages)++;
}
return rc;
}
static int cifs_readpages(struct file *file, struct address_space *mapping,
struct list_head *page_list, unsigned num_pages)
{
@ -3394,57 +3451,15 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
* the rdata->pages, then we want them in increasing order.
*/
while (!list_empty(page_list)) {
unsigned int i;
unsigned int bytes = PAGE_CACHE_SIZE;
unsigned int expected_index;
unsigned int nr_pages = 1;
unsigned int i, nr_pages, bytes;
loff_t offset;
struct page *page, *tpage;
struct cifs_readdata *rdata;
page = list_entry(page_list->prev, struct page, lru);
/*
* Lock the page and put it in the cache. Since no one else
* should have access to this page, we're safe to simply set
* PG_locked without checking it first.
*/
__set_page_locked(page);
rc = add_to_page_cache_locked(page, mapping,
page->index, GFP_KERNEL);
/* give up if we can't stick it in the cache */
if (rc) {
__clear_page_locked(page);
rc = readpages_get_pages(mapping, page_list, rsize, &tmplist,
&nr_pages, &offset, &bytes);
if (rc)
break;
}
/* move first page to the tmplist */
offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
list_move_tail(&page->lru, &tmplist);
/* now try and add more pages onto the request */
expected_index = page->index + 1;
list_for_each_entry_safe_reverse(page, tpage, page_list, lru) {
/* discontinuity ? */
if (page->index != expected_index)
break;
/* would this page push the read over the rsize? */
if (bytes + PAGE_CACHE_SIZE > rsize)
break;
__set_page_locked(page);
if (add_to_page_cache_locked(page, mapping,
page->index, GFP_KERNEL)) {
__clear_page_locked(page);
break;
}
list_move_tail(&page->lru, &tmplist);
bytes += PAGE_CACHE_SIZE;
expected_index++;
nr_pages++;
}
rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
if (!rdata) {