[PATCH 3/3] zram: remove swap_slot_free_notify

[Minchan Kim <minchan@kernel.org>]

Frontswap replaces the need for swap_slot_free_notify in block_device.
Therefore, we can remove it.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 Documentation/filesystems/locking.rst |  5 -----
 drivers/block/zram/zram_drv.c         | 20 +-------------------
 include/linux/blkdev.h                |  2 --
 mm/swapfile.c                         |  8 --------
 4 files changed, 1 insertion(+), 34 deletions(-)

diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index aa1a233b0fa8..c94ef7d9fc6e 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -477,7 +477,6 @@ block_device_operations
 				unsigned long *);
 	void (*unlock_native_capacity) (struct gendisk *);
 	int (*getgeo)(struct block_device *, struct hd_geometry *);
-	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
 
 locking rules:
 
@@ -491,12 +490,8 @@ compat_ioctl:		no
 direct_access:		no
 unlock_native_capacity:	no
 getgeo:			no
-swap_slot_free_notify:	no	(see below)
 ======================= ===================
 
-swap_slot_free_notify is called with swap_lock and sometimes the page lock
-held.
-
 
 file_operations
 ===============
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 5e973c982235..ec040ab3ab91 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1947,23 +1947,6 @@ static void zram_submit_bio(struct bio *bio)
 	}
 }
 
-static void zram_slot_free_notify(struct block_device *bdev,
-				unsigned long index)
-{
-	struct zram *zram;
-
-	zram = bdev->bd_disk->private_data;
-
-	atomic64_inc(&zram->stats.notify_free);
-	if (!zram_slot_trylock(zram, index)) {
-		atomic64_inc(&zram->stats.miss_free);
-		return;
-	}
-
-	zram_free_page(zram, index);
-	zram_slot_unlock(zram, index);
-}
-
 static void zram_destroy_comps(struct zram *zram)
 {
 	u32 prio;
@@ -2117,7 +2100,6 @@ static int zram_open(struct block_device *bdev, fmode_t mode)
 static const struct block_device_operations zram_devops = {
 	.open = zram_open,
 	.submit_bio = zram_submit_bio,
-	.swap_slot_free_notify = zram_slot_free_notify,
 	.owner = THIS_MODULE
 };
 
@@ -2206,7 +2188,7 @@ static int zram_frontswap_load(unsigned int type, pgoff_t index,
 
 	err = zram_read_from_zspool(zram, page, index);
 	if (!err)
-		zram_accessed(zram, index);
+		zram_free_page(zram, index);
 	zram_slot_unlock(zram, index);
 
 	return err;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c0ffe203a602..49e1843e44ea 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1390,8 +1390,6 @@ struct block_device_operations {
 	int (*getgeo)(struct block_device *, struct hd_geometry *);
 	int (*set_read_only)(struct block_device *bdev, bool ro);
 	void (*free_disk)(struct gendisk *disk);
-	/* this callback is with swap_lock and sometimes page table lock held */
-	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
 	int (*report_zones)(struct gendisk *, sector_t sector,
 			unsigned int nr_zones, report_zones_cb cb, void *data);
 	char *(*devnode)(struct gendisk *disk, umode_t *mode);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index a9424fd226bc..adc16d8883c8 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -726,7 +726,6 @@ static void swap_range_free(struct swap_info_struct *si, unsigned long offset,
 {
 	unsigned long begin = offset;
 	unsigned long end = offset + nr_entries - 1;
-	void (*swap_slot_free_notify)(struct block_device *, unsigned long);
 
 	if (offset < si->lowest_bit)
 		si->lowest_bit = offset;
@@ -739,16 +738,9 @@ static void swap_range_free(struct swap_info_struct *si, unsigned long offset,
 	}
 	atomic_long_add(nr_entries, &nr_swap_pages);
 	WRITE_ONCE(si->inuse_pages, si->inuse_pages - nr_entries);
-	if (si->flags & SWP_BLKDEV)
-		swap_slot_free_notify =
-			si->bdev->bd_disk->fops->swap_slot_free_notify;
-	else
-		swap_slot_free_notify = NULL;
 	while (offset <= end) {
 		arch_swap_invalidate_page(si->type, offset);
 		frontswap_invalidate_page(si->type, offset);
-		if (swap_slot_free_notify)
-			swap_slot_free_notify(si->bdev, offset);
 		offset++;
 	}
 	clear_shadow_from_swap_cache(si->type, begin, end);
-- 
2.41.0.255.g8b1d071c50-goog