From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Use the new readahead operation in CIFS
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/cifs/file.c | 143 +++++++++----------------------------------------
1 file changed, 25 insertions(+), 118 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 043288b5c728..c9162380ad22 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -4280,70 +4280,11 @@ cifs_readpages_copy_into_pages(struct TCP_Server_Info *server,
return readpages_fill_pages(server, rdata, iter, iter->count);
}
-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;
- gfp_t gfp = readahead_gfp_mask(mapping);
-
- INIT_LIST_HEAD(tmplist);
-
- page = lru_to_page(page_list);
-
- /*
- * 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.
- */
- __SetPageLocked(page);
- rc = add_to_page_cache_locked(page, mapping,
- page->index, gfp);
-
- /* give up if we can't stick it in the cache */
- if (rc) {
- __ClearPageLocked(page);
- return rc;
- }
-
- /* move first page to the tmplist */
- *offset = (loff_t)page->index << PAGE_SHIFT;
- *bytes = PAGE_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_SIZE > rsize)
- break;
-
- __SetPageLocked(page);
- if (add_to_page_cache_locked(page, mapping, page->index, gfp)) {
- __ClearPageLocked(page);
- break;
- }
- list_move_tail(&page->lru, tmplist);
- (*bytes) += PAGE_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)
+static unsigned cifs_readahead(struct file *file,
+ struct address_space *mapping, pgoff_t start,
+ unsigned num_pages)
{
int rc;
- struct list_head tmplist;
struct cifsFileInfo *open_file = file->private_data;
struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
struct TCP_Server_Info *server;
@@ -4358,11 +4299,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
* After this point, every page in the list might have PG_fscache set,
* so we will need to clean that up off of every page we don't use.
*/
- rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
- &num_pages);
+ rc = -ENOBUFS;
if (rc == 0) {
free_xid(xid);
- return rc;
+ return num_pages;
}
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
@@ -4373,24 +4313,11 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
rc = 0;
server = tlink_tcon(open_file->tlink)->ses->server;
- cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
- __func__, file, mapping, num_pages);
+ cifs_dbg(FYI, "%s: file=%p mapping=%p start=%lu num_pages=%u\n",
+ __func__, file, mapping, start, num_pages);
- /*
- * Start with the page at end of list and move it to private
- * list. Do the same with any following pages until we hit
- * the rsize limit, hit an index discontinuity, or run out of
- * pages. Issue the async read and then start the loop again
- * until the list is empty.
- *
- * Note that list order is important. The page_list is in
- * the order of declining indexes. When we put the pages in
- * the rdata->pages, then we want them in increasing order.
- */
- while (!list_empty(page_list)) {
- unsigned int i, nr_pages, bytes, rsize;
- loff_t offset;
- struct page *page, *tpage;
+ while (num_pages) {
+ unsigned int i, nr_pages, rsize;
struct cifs_readdata *rdata;
struct cifs_credits credits_on_stack;
struct cifs_credits *credits = &credits_on_stack;
@@ -4408,21 +4335,14 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
if (rc)
break;
+ nr_pages = min_t(unsigned, rsize / PAGE_SIZE, num_pages);
/*
* Give up immediately if rsize is too small to read an entire
* page. The VFS will fall back to readpage. We should never
- * reach this point however since we set ra_pages to 0 when the
- * rsize is smaller than a cache page.
+ * reach this point however since we set ra_pages to 0 when
+ * the rsize is smaller than a cache page.
*/
- if (unlikely(rsize < PAGE_SIZE)) {
- add_credits_and_wake_if(server, credits, 0);
- free_xid(xid);
- return 0;
- }
-
- rc = readpages_get_pages(mapping, page_list, rsize, &tmplist,
- &nr_pages, &offset, &bytes);
- if (rc) {
+ if (unlikely(nr_pages < 1)) {
add_credits_and_wake_if(server, credits, 0);
break;
}
@@ -4430,21 +4350,15 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
if (!rdata) {
/* best to give up if we're out of mem */
- list_for_each_entry_safe(page, tpage, &tmplist, lru) {
- list_del(&page->lru);
- lru_cache_add_file(page);
- unlock_page(page);
- put_page(page);
- }
- rc = -ENOMEM;
add_credits_and_wake_if(server, credits, 0);
break;
}
rdata->cfile = cifsFileInfo_get(open_file);
rdata->mapping = mapping;
- rdata->offset = offset;
- rdata->bytes = bytes;
+ rdata->offset = start;
+ rdata->nr_pages = nr_pages;
+ rdata->bytes = nr_pages * PAGE_SIZE;
rdata->pid = pid;
rdata->pagesz = PAGE_SIZE;
rdata->tailsz = PAGE_SIZE;
@@ -4452,10 +4366,8 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
rdata->copy_into_pages = cifs_readpages_copy_into_pages;
rdata->credits = credits_on_stack;
- list_for_each_entry_safe(page, tpage, &tmplist, lru) {
- list_del(&page->lru);
- rdata->pages[rdata->nr_pages++] = page;
- }
+ for (i = 0; i < nr_pages; i++)
+ rdata->pages[i] = readahead_page(mapping, start++);
rc = adjust_credits(server, &rdata->credits, rdata->bytes);
@@ -4468,27 +4380,22 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
if (rc) {
add_credits_and_wake_if(server, &rdata->credits, 0);
- for (i = 0; i < rdata->nr_pages; i++) {
- page = rdata->pages[i];
- lru_cache_add_file(page);
- unlock_page(page);
- put_page(page);
- }
- /* Fallback to the readpage in error/reconnect cases */
kref_put(&rdata->refcount, cifs_readdata_release);
break;
}
kref_put(&rdata->refcount, cifs_readdata_release);
+ num_pages -= nr_pages;
}
/* Any pages that have been shown to fscache but didn't get added to
* the pagecache must be uncached before they get returned to the
* allocator.
*/
- cifs_fscache_readpages_cancel(mapping->host, page_list);
+// cifs_fscache_readpages_cancel(mapping->host, page_list);
free_xid(xid);
- return rc;
+
+ return num_pages;
}
/*
@@ -4806,7 +4713,7 @@ cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter)
const struct address_space_operations cifs_addr_ops = {
.readpage = cifs_readpage,
- .readpages = cifs_readpages,
+ .readahead = cifs_readahead,
.writepage = cifs_writepage,
.writepages = cifs_writepages,
.write_begin = cifs_write_begin,
@@ -4819,9 +4726,9 @@ const struct address_space_operations cifs_addr_ops = {
};
/*
- * cifs_readpages requires the server to support a buffer large enough to
+ * cifs_readahead requires the server to support a buffer large enough to
* contain the header plus one complete page of data. Otherwise, we need
- * to leave cifs_readpages out of the address space operations.
+ * to leave cifs_readahead out of the address space operations.
*/
const struct address_space_operations cifs_addr_ops_smallbuf = {
.readpage = cifs_readpage,
--
2.24.1
