Commit 78d6a12d authored by Kairui Song's avatar Kairui Song Committed by Andrew Morton
Browse files

mm, swap: split locked entry duplicating into a standalone helper 

No feature change, split the common logic into a stand alone helper to be
reused later.

Link: https://lkml.kernel.org/r/20251220-swap-table-p2-v5-11-8862a265a033@tencent.com


Signed-off-by: default avatarKairui Song <kasong@tencent.com>
Reviewed-by: default avatarBaoquan He <bhe@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: Deepanshu Kartikey <kartikey406@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <ryncsn@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent cda2504c

mm/swapfile.c

+31 −31
Original line number Diff line number Diff line
@@ -3667,26 +3667,14 @@ void si_swapinfo(struct sysinfo *val) 
 * - swap-cache reference is requested but the entry is not used. -> ENOENT

 * - swap-mapped reference requested but needs continued swap count. -> ENOMEM

 */

static int __swap_duplicate(swp_entry_t entry, unsigned char usage, int nr)

static int swap_dup_entries(struct swap_info_struct *si,

			    struct swap_cluster_info *ci,

			    unsigned long offset,

			    unsigned char usage, int nr)

{

	struct swap_info_struct *si;

	struct swap_cluster_info *ci;

	unsigned long offset;

	unsigned char count;

	unsigned char has_cache;

	int err, i;



	si = swap_entry_to_info(entry);

	if (WARN_ON_ONCE(!si)) {

		pr_err("%s%08lx\n", Bad_file, entry.val);

		return -EINVAL;

	}



	offset = swp_offset(entry);

	VM_WARN_ON(nr > SWAPFILE_CLUSTER - offset % SWAPFILE_CLUSTER);

	ci = swap_cluster_lock(si, offset);

	int i;

	unsigned char count, has_cache;



	err = 0;

	for (i = 0; i < nr; i++) {

		count = si->swap_map[offset + i];
@@ -3694,25 +3682,20 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage, int nr) 
		 * For swapin out, allocator never allocates bad slots. for

		 * swapin, readahead is guarded by swap_entry_swapped.

		 */

		if (WARN_ON(swap_count(count) == SWAP_MAP_BAD)) {

			err = -ENOENT;

			goto unlock_out;

		}

		if (WARN_ON(swap_count(count) == SWAP_MAP_BAD))

			return -ENOENT;



		has_cache = count & SWAP_HAS_CACHE;

		count &= ~SWAP_HAS_CACHE;



		if (!count && !has_cache) {

			err = -ENOENT;

			return -ENOENT;

		} else if (usage == SWAP_HAS_CACHE) {

			if (has_cache)

				err = -EEXIST;

				return -EEXIST;

		} else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) {

			err = -EINVAL;

			return -EINVAL;

		}



		if (err)

			goto unlock_out;

	}



	for (i = 0; i < nr; i++) {
@@ -3731,14 +3714,31 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage, int nr) 
			 * Don't need to rollback changes, because if

			 * usage == 1, there must be nr == 1.

			 */

			err = -ENOMEM;

			goto unlock_out;

			return -ENOMEM;

		}



		WRITE_ONCE(si->swap_map[offset + i], count | has_cache);

	}



unlock_out:

	return 0;

}



static int __swap_duplicate(swp_entry_t entry, unsigned char usage, int nr)

{

	int err;

	struct swap_info_struct *si;

	struct swap_cluster_info *ci;

	unsigned long offset = swp_offset(entry);



	si = swap_entry_to_info(entry);

	if (WARN_ON_ONCE(!si)) {

		pr_err("%s%08lx\n", Bad_file, entry.val);

		return -EINVAL;

	}



	VM_WARN_ON(nr > SWAPFILE_CLUSTER - offset % SWAPFILE_CLUSTER);

	ci = swap_cluster_lock(si, offset);

	err = swap_dup_entries(si, ci, offset, usage, nr);

	swap_cluster_unlock(ci);

	return err;

}