[PATCH 08/12] erofs: Convert compressed files from readpages to readahead

From: Matthew Wilcox
Date: Fri Jan 24 2020 - 20:36:02 EST


From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>

Use the new readahead operation in erofs.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: linux-erofs@xxxxxxxxxxxxxxxx
---
fs/erofs/zdata.c | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index d3dd8cf1fc01..20efb87dd957 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1328,28 +1328,26 @@ static bool should_decompress_synchronously(struct erofs_sb_info *sbi,
return nr <= sbi->max_sync_decompress_pages;
}

-static int z_erofs_readpages(struct file *filp, struct address_space *mapping,
- struct list_head *pages, unsigned int nr_pages)
+static
+unsigned z_erofs_readahead(struct file *file, struct address_space *mapping,
+ pgoff_t start, unsigned int nr_pages)
{
struct inode *const inode = mapping->host;
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);

bool sync = should_decompress_synchronously(sbi, nr_pages);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
- gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);
struct page *head = NULL;
LIST_HEAD(pagepool);

- trace_erofs_readpages(mapping->host, lru_to_page(pages)->index,
- nr_pages, false);
+ trace_erofs_readpages(inode, start, nr_pages, false);

- f.headoffset = (erofs_off_t)lru_to_page(pages)->index << PAGE_SHIFT;
+ f.headoffset = (erofs_off_t)start << PAGE_SHIFT;

for (; nr_pages; --nr_pages) {
- struct page *page = lru_to_page(pages);
+ struct page *page = readahead_page(mapping, start);

prefetchw(&page->flags);
- list_del(&page->lru);

/*
* A pure asynchronous readahead is indicated if
@@ -1358,11 +1356,6 @@ static int z_erofs_readpages(struct file *filp, struct address_space *mapping,
*/
sync &= !(PageReadahead(page) && !head);

- if (add_to_page_cache_lru(page, mapping, page->index, gfp)) {
- list_add(&page->lru, &pagepool);
- continue;
- }
-
set_page_private(page, (unsigned long)head);
head = page;
}
@@ -1396,6 +1389,6 @@ static int z_erofs_readpages(struct file *filp, struct address_space *mapping,

const struct address_space_operations z_erofs_aops = {
.readpage = z_erofs_readpage,
- .readpages = z_erofs_readpages,
+ .readahead = z_erofs_readahead,
};

--
2.24.1