Re: [PATCH 2/2] fs: Don't open-code lru_to_page

From: Michal Hocko
Date: Thu Nov 29 2018 - 03:18:35 EST

On Thu 29-11-18 09:52:57, Nikolay Borisov wrote:
> There are a bunch of filesystems which essentially open-code lru_to_page
> helper. Change them to using the helper. No functional changes.

I would just squash the two into a single patch. It makes the first one
more obvious. Or is there any reason to have them separate?

> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxxx>

> ---
>
> Since this is a mostly mechanical change I've actually batched all of them in
> a single patch.
>
> fs/afs/file.c | 5 +++--
> fs/btrfs/extent_io.c | 2 +-
> fs/ceph/addr.c | 5 ++---
> fs/cifs/file.c | 3 ++-
> fs/ext4/readpage.c | 2 +-
> fs/ocfs2/aops.c | 3 ++-
> fs/orangefs/inode.c | 2 +-
> mm/swap.c | 2 +-
> 8 files changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/fs/afs/file.c b/fs/afs/file.c
> index d6bc3f5d784b..323ae9912203 100644
> --- a/fs/afs/file.c
> +++ b/fs/afs/file.c
> @@ -17,6 +17,7 @@
> #include <linux/writeback.h>
> #include <linux/gfp.h>
> #include <linux/task_io_accounting_ops.h>
> +#include <linux/mm.h>
> #include "internal.h"
>
> static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
> @@ -441,7 +442,7 @@ static int afs_readpages_one(struct file *file, struct address_space *mapping,
> /* Count the number of contiguous pages at the front of the list. Note
> * that the list goes prev-wards rather than next-wards.
> */
> - first = list_entry(pages->prev, struct page, lru);
> + first = lru_to_page(pages);
> index = first->index + 1;
> n = 1;
> for (p = first->lru.prev; p != pages; p = p->prev) {
> @@ -473,7 +474,7 @@ static int afs_readpages_one(struct file *file, struct address_space *mapping,
> * page at the end of the file.
> */
> do {
> - page = list_entry(pages->prev, struct page, lru);
> + page = lru_to_page(pages);
> list_del(&page->lru);
> index = page->index;
> if (add_to_page_cache_lru(page, mapping, index,
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 19f4b8fd654f..8332c5f4b1c3 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4104,7 +4104,7 @@ int extent_readpages(struct address_space *mapping, struct list_head *pages,
> u64 prev_em_start = (u64)-1;
>
> for (page_idx = 0; page_idx < nr_pages; page_idx++) {
> - page = list_entry(pages->prev, struct page, lru);
> + page = lru_to_page(pages);
>
> prefetchw(&page->flags);
> list_del(&page->lru);
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index 8eade7a993c1..5d0c05e288cc 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -306,7 +306,7 @@ static int start_read(struct inode *inode, struct ceph_rw_context *rw_ctx,
> struct ceph_osd_client *osdc =
> &ceph_inode_to_client(inode)->client->osdc;
> struct ceph_inode_info *ci = ceph_inode(inode);
> - struct page *page = list_entry(page_list->prev, struct page, lru);
> + struct page *page = lru_to_page(page_list);
> struct ceph_vino vino;
> struct ceph_osd_request *req;
> u64 off;
> @@ -333,8 +333,7 @@ static int start_read(struct inode *inode, struct ceph_rw_context *rw_ctx,
> if (got)
> ceph_put_cap_refs(ci, got);
> while (!list_empty(page_list)) {
> - page = list_entry(page_list->prev,
> - struct page, lru);
> + page = lru_to_page(page_list);
> list_del(&page->lru);
> put_page(page);
> }
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 74c33d5fafc8..b16a4d887d17 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -33,6 +33,7 @@
> #include <linux/mount.h>
> #include <linux/slab.h>
> #include <linux/swap.h>
> +#include <linux/mm.h>
> #include <asm/div64.h>
> #include "cifsfs.h"
> #include "cifspdu.h"
> @@ -3975,7 +3976,7 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
>
> INIT_LIST_HEAD(tmplist);
>
> - page = list_entry(page_list->prev, struct page, lru);
> + page = lru_to_page(page_list);
>
> /*
> * Lock the page and put it in the cache. Since no one else
> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
> index f461d75ac049..6aa282ee455a 100644
> --- a/fs/ext4/readpage.c
> +++ b/fs/ext4/readpage.c
> @@ -128,7 +128,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
>
> prefetchw(&page->flags);
> if (pages) {
> - page = list_entry(pages->prev, struct page, lru);
> + page = lru_to_page(pages);
> list_del(&page->lru);
> if (add_to_page_cache_lru(page, mapping, page->index,
> readahead_gfp_mask(mapping)))
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index eb1ce30412dc..832c1759a09a 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -30,6 +30,7 @@
> #include <linux/quotaops.h>
> #include <linux/blkdev.h>
> #include <linux/uio.h>
> +#include <linux/mm.h>
>
> #include <cluster/masklog.h>
>
> @@ -397,7 +398,7 @@ static int ocfs2_readpages(struct file *filp, struct address_space *mapping,
> * Check whether a remote node truncated this file - we just
> * drop out in that case as it's not worth handling here.
> */
> - last = list_entry(pages->prev, struct page, lru);
> + last = lru_to_page(pages);
> start = (loff_t)last->index << PAGE_SHIFT;
> if (start >= i_size_read(inode))
> goto out_unlock;
> diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
> index fe53381b26b1..f038235c64bd 100644
> --- a/fs/orangefs/inode.c
> +++ b/fs/orangefs/inode.c
> @@ -77,7 +77,7 @@ static int orangefs_readpages(struct file *file,
> for (page_idx = 0; page_idx < nr_pages; page_idx++) {
> struct page *page;
>
> - page = list_entry(pages->prev, struct page, lru);
> + page = lru_to_page(pages);
> list_del(&page->lru);
> if (!add_to_page_cache(page,
> mapping,
> diff --git a/mm/swap.c b/mm/swap.c
> index aa483719922e..20b9e9d99652 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -126,7 +126,7 @@ void put_pages_list(struct list_head *pages)
> while (!list_empty(pages)) {
> struct page *victim;
>
> - victim = list_entry(pages->prev, struct page, lru);
> + victim = lru_to_page(pages);
> list_del(&victim->lru);
> put_page(victim);
> }
> --
> 2.17.1

--
Michal Hocko
SUSE Labs