Hello,
On Mon, Jul 10, 2023 at 03:16:59PM -0700, Minchan Kim wrote:
> Frontswap replaces the need for swap_slot_free_notify in block_device.
> Therefore, we can remove it.
>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> ---
> 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);
Probably it should be in the previous commit.
> 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
>
>
--
Thank you,
Alexey
