We should fold scan_swap_map() into the only caller get_swap_page_of_type()
and update the comments referring to it to make the code more succinct.
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
Hi Andrew,
Please feel free to merge this with
mm-swapfile-move-get_swap_page_of_type-under-config_hibernation.patch and
mm-swapfile-move-get_swap_page_of_type-under-config_hibernation-fix.patch
Many thanks!
---
mm/swapfile.c | 57 ++++++++++++++++-----------------------------------
1 file changed, 18 insertions(+), 39 deletions(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 53d2161edfc0..166be489664d 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -453,10 +453,10 @@ static void swap_cluster_schedule_discard(struct swap_info_struct *si,
unsigned int idx)
{
/*
- * If scan_swap_map() can't find a free cluster, it will check
+ * If scan_swap_map_slots() can't find a free cluster, it will check
* si->swap_map directly. To make sure the discarding cluster isn't
- * taken by scan_swap_map(), mark the swap entries bad (occupied). It
- * will be cleared after discard
+ * taken by scan_swap_map_slots(), mark the swap entries bad (occupied).
+ * It will be cleared after discard
*/
memset(si->swap_map + idx * SWAPFILE_CLUSTER,
SWAP_MAP_BAD, SWAPFILE_CLUSTER);
@@ -589,7 +589,7 @@ static void dec_cluster_info_page(struct swap_info_struct *p,
}
/*
- * It's possible scan_swap_map() uses a free cluster in the middle of free
+ * It's possible scan_swap_map_slots() uses a free cluster in the middle of free
* cluster list. Avoiding such abuse to avoid list corruption.
*/
static bool
@@ -1099,14 +1099,14 @@ int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_size)
nextsi:
/*
* if we got here, it's likely that si was almost full before,
- * and since scan_swap_map() can drop the si->lock, multiple
- * callers probably all tried to get a page from the same si
- * and it filled up before we could get one; or, the si filled
- * up between us dropping swap_avail_lock and taking si->lock.
- * Since we dropped the swap_avail_lock, the swap_avail_head
- * list may have been modified; so if next is still in the
- * swap_avail_head list then try it, otherwise start over
- * if we have not gotten any slots.
+ * and since scan_swap_map_slots() can drop the si->lock,
+ * multiple callers probably all tried to get a page from the
+ * same si and it filled up before we could get one; or, the si
+ * filled up between us dropping swap_avail_lock and taking
+ * si->lock. Since we dropped the swap_avail_lock, the
+ * swap_avail_head list may have been modified; so if next is
+ * still in the swap_avail_head list then try it, otherwise
+ * start over if we have not gotten any slots.
*/
if (plist_node_empty(&next->avail_lists[node]))
goto start_over;
@@ -1774,42 +1774,21 @@ int free_swap_and_cache(swp_entry_t entry)
#ifdef CONFIG_HIBERNATION
-static unsigned long scan_swap_map(struct swap_info_struct *si,
- unsigned char usage)
-{
- swp_entry_t entry;
- int n_ret;
-
- n_ret = scan_swap_map_slots(si, usage, 1, &entry);
-
- if (n_ret)
- return swp_offset(entry);
- else
- return 0;
-
-}
-
swp_entry_t get_swap_page_of_type(int type)
{
struct swap_info_struct *si = swap_type_to_swap_info(type);
- pgoff_t offset;
+ swp_entry_t entry = {0};
if (!si)
goto fail;
+ /* This is called for allocating swap entry, not cache */
spin_lock(&si->lock);
- if (si->flags & SWP_WRITEOK) {
- /* This is called for allocating swap entry, not cache */
- offset = scan_swap_map(si, 1);
- if (offset) {
- atomic_long_dec(&nr_swap_pages);
- spin_unlock(&si->lock);
- return swp_entry(type, offset);
- }
- }
+ if ((si->flags & SWP_WRITEOK) && scan_swap_map_slots(si, 1, 1, &entry))
+ atomic_long_dec(&nr_swap_pages);
spin_unlock(&si->lock);
fail:
- return (swp_entry_t) {0};
+ return entry;
}
/*
@@ -2649,7 +2628,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
spin_lock(&p->lock);
drain_mmlist();
- /* wait for anyone still in scan_swap_map */
+ /* wait for anyone still in scan_swap_map_slots */
p->highest_bit = 0; /* cuts scans short */
while (p->flags >= SWP_SCANNING) {
spin_unlock(&p->lock);
--
2.23.0
