blkcg, writeback: Rename wbc_account_io() to wbc_account_cgroup_owner()

wbc_account_io() does a very specific job - try to see which cgroup is
actually dirtying an inode and transfer its ownership to the majority
dirtier if needed.  The name is too generic and confusing.  Let's
rename it to something more specific.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/admin-guide/cgroup-v2.rst

@@ -2114,7 +2114,7 @@ following two functions.
 	a queue (device) has been associated with the bio and
 	before submission.
 
-  wbc_account_io(@wbc, @page, @bytes)
+  wbc_account_cgroup_owner(@wbc, @page, @bytes)
 	Should be called for each data segment being written out.
 	While this function doesn't care exactly when it's called
 	during the writeback session, it's the easiest and most

fs/btrfs/extent_io.c

@@ -2911,7 +2911,7 @@ static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
 			bio = NULL;
 		} else {
 			if (wbc)
-				wbc_account_io(wbc, page, page_size);
+				wbc_account_cgroup_owner(wbc, page, page_size);
 			return 0;
 		}
 	}
@@ -2924,7 +2924,7 @@ static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
 	bio->bi_opf = opf;
 	if (wbc) {
 		wbc_init_bio(wbc, bio);
-		wbc_account_io(wbc, page, page_size);
+		wbc_account_cgroup_owner(wbc, page, page_size);
 	}
 
 	*bio_ret = bio;

fs/buffer.c

@@ -3093,7 +3093,7 @@ static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
 
 	if (wbc) {
 		wbc_init_bio(wbc, bio);
-		wbc_account_io(wbc, bh->b_page, bh->b_size);
+		wbc_account_cgroup_owner(wbc, bh->b_page, bh->b_size);
 	}
 
 	submit_bio(bio);

fs/ext4/page-io.c

@@ -404,7 +404,7 @@ static int io_submit_add_bh(struct ext4_io_submit *io,
 	ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
 	if (ret != bh->b_size)
 		goto submit_and_retry;
-	wbc_account_io(io->io_wbc, page, bh->b_size);
+	wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size);
 	io->io_next_block++;
 	return 0;
 }

fs/f2fs/data.c

@@ -470,7 +470,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 	}
 
 	if (fio->io_wbc && !is_read_io(fio->op))
-		wbc_account_io(fio->io_wbc, page, PAGE_SIZE);
+		wbc_account_cgroup_owner(fio->io_wbc, page, PAGE_SIZE);
 
 	bio_set_op_attrs(bio, fio->op, fio->op_flags);
 
@@ -537,7 +537,7 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	}
 
 	if (fio->io_wbc)
-		wbc_account_io(fio->io_wbc, bio_page, PAGE_SIZE);
+		wbc_account_cgroup_owner(fio->io_wbc, bio_page, PAGE_SIZE);
 
 	io->last_block_in_bio = fio->new_blkaddr;
 	f2fs_trace_ios(fio, 0);

fs/fs-writeback.c

@@ -706,7 +706,7 @@ void wbc_detach_inode(struct writeback_control *wbc)
 EXPORT_SYMBOL_GPL(wbc_detach_inode);
 
 /**
- * wbc_account_io - account IO issued during writeback
+ * wbc_account_cgroup_owner - account writeback to update inode cgroup ownership
  * @wbc: writeback_control of the writeback in progress
  * @page: page being written out
  * @bytes: number of bytes being written out
@@ -715,8 +715,8 @@ EXPORT_SYMBOL_GPL(wbc_detach_inode);
  * controlled by @wbc.  Keep the book for foreign inode detection.  See
  * wbc_detach_inode().
  */
-void wbc_account_io(struct writeback_control *wbc, struct page *page,
-		    size_t bytes)
+void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page,
+			      size_t bytes)
 {
 	struct cgroup_subsys_state *css;
 	int id;
@@ -753,7 +753,7 @@ void wbc_account_io(struct writeback_control *wbc, struct page *page,
 	else
 		wbc->wb_tcand_bytes -= min(bytes, wbc->wb_tcand_bytes);
 }
-EXPORT_SYMBOL_GPL(wbc_account_io);
+EXPORT_SYMBOL_GPL(wbc_account_cgroup_owner);
 
 /**
  * inode_congested - test whether an inode is congested

fs/mpage.c

@@ -647,7 +647,7 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
 	 * the confused fail path above (OOM) will be very confused when
 	 * it finds all bh marked clean (i.e. it will not write anything)
 	 */
-	wbc_account_io(wbc, page, PAGE_SIZE);
+	wbc_account_cgroup_owner(wbc, page, PAGE_SIZE);
 	length = first_unmapped << blkbits;
 	if (bio_add_page(bio, page, length, 0) < length) {
 		bio = mpage_bio_submit(REQ_OP_WRITE, op_flags, bio);

include/linux/writeback.h

@@ -188,8 +188,8 @@ void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
 				 struct inode *inode)
 	__releases(&inode->i_lock);
 void wbc_detach_inode(struct writeback_control *wbc);
-void wbc_account_io(struct writeback_control *wbc, struct page *page,
-		    size_t bytes);
+void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page,
+			      size_t bytes);
 void cgroup_writeback_umount(void);
 
 /**
@@ -291,8 +291,8 @@ static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio)
 {
 }
 
-static inline void wbc_account_io(struct writeback_control *wbc,
-				  struct page *page, size_t bytes)
+static inline void wbc_account_cgroup_owner(struct writeback_control *wbc,
+					    struct page *page, size_t bytes)
 {
 }