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

[Michal Hocko <mhocko@kernel.org>]

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@suse.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
> 
> 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