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-rw-r--r--include/linux/swap.h2
-rw-r--r--mm/swapfile.c70
2 files changed, 37 insertions, 35 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index f1c2487..109dfe7 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -165,7 +165,7 @@ struct swap_info_struct {
signed char next; /* next type on the swap list */
struct file *swap_file;
struct block_device *bdev;
- struct list_head extent_list;
+ struct swap_extent first_swap_extent;
struct swap_extent *curr_swap_extent;
unsigned short *swap_map;
unsigned int lowest_bit;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index dc88a7e..16de84b 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -145,23 +145,28 @@ void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page)
static int discard_swap(struct swap_info_struct *si)
{
struct swap_extent *se;
+ sector_t start_block;
+ sector_t nr_blocks;
int err = 0;
- list_for_each_entry(se, &si->extent_list, list) {
- sector_t start_block = se->start_block << (PAGE_SHIFT - 9);
- sector_t nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9);
+ /* Do not discard the swap header page! */
+ se = &si->first_swap_extent;
+ start_block = (se->start_block + 1) << (PAGE_SHIFT - 9);
+ nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9);
+ if (nr_blocks) {
+ err = blkdev_issue_discard(si->bdev, start_block,
+ nr_blocks, GFP_KERNEL, DISCARD_FL_BARRIER);
+ if (err)
+ return err;
+ cond_resched();
+ }
- if (se->start_page == 0) {
- /* Do not discard the swap header page! */
- start_block += 1 << (PAGE_SHIFT - 9);
- nr_blocks -= 1 << (PAGE_SHIFT - 9);
- if (!nr_blocks)
- continue;
- }
+ list_for_each_entry(se, &si->first_swap_extent.list, list) {
+ start_block = se->start_block << (PAGE_SHIFT - 9);
+ nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9);
err = blkdev_issue_discard(si->bdev, start_block,
- nr_blocks, GFP_KERNEL,
- DISCARD_FL_BARRIER);
+ nr_blocks, GFP_KERNEL, DISCARD_FL_BARRIER);
if (err)
break;
@@ -200,14 +205,11 @@ static void discard_swap_cluster(struct swap_info_struct *si,
start_block <<= PAGE_SHIFT - 9;
nr_blocks <<= PAGE_SHIFT - 9;
if (blkdev_issue_discard(si->bdev, start_block,
- nr_blocks, GFP_NOIO,
- DISCARD_FL_BARRIER))
+ nr_blocks, GFP_NOIO, DISCARD_FL_BARRIER))
break;
}
lh = se->list.next;
- if (lh == &si->extent_list)
- lh = lh->next;
se = list_entry(lh, struct swap_extent, list);
}
}
@@ -761,10 +763,8 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p)
return type;
}
if (bdev == sis->bdev) {
- struct swap_extent *se;
+ struct swap_extent *se = &sis->first_swap_extent;
- se = list_entry(sis->extent_list.next,
- struct swap_extent, list);
if (se->start_block == offset) {
if (bdev_p)
*bdev_p = bdgrab(sis->bdev);
@@ -1310,8 +1310,6 @@ sector_t map_swap_page(swp_entry_t entry, struct block_device **bdev)
return se->start_block + (offset - se->start_page);
}
lh = se->list.next;
- if (lh == &sis->extent_list)
- lh = lh->next;
se = list_entry(lh, struct swap_extent, list);
sis->curr_swap_extent = se;
BUG_ON(se == start_se); /* It *must* be present */
@@ -1340,10 +1338,10 @@ sector_t swapdev_block(int type, pgoff_t offset)
*/
static void destroy_swap_extents(struct swap_info_struct *sis)
{
- while (!list_empty(&sis->extent_list)) {
+ while (!list_empty(&sis->first_swap_extent.list)) {
struct swap_extent *se;
- se = list_entry(sis->extent_list.next,
+ se = list_entry(sis->first_swap_extent.list.next,
struct swap_extent, list);
list_del(&se->list);
kfree(se);
@@ -1364,8 +1362,15 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
struct swap_extent *new_se;
struct list_head *lh;
- lh = sis->extent_list.prev; /* The highest page extent */
- if (lh != &sis->extent_list) {
+ if (start_page == 0) {
+ se = &sis->first_swap_extent;
+ sis->curr_swap_extent = se;
+ se->start_page = 0;
+ se->nr_pages = nr_pages;
+ se->start_block = start_block;
+ return 1;
+ } else {
+ lh = sis->first_swap_extent.list.prev; /* Highest extent */
se = list_entry(lh, struct swap_extent, list);
BUG_ON(se->start_page + se->nr_pages != start_page);
if (se->start_block + se->nr_pages == start_block) {
@@ -1385,7 +1390,7 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
new_se->nr_pages = nr_pages;
new_se->start_block = start_block;
- list_add_tail(&new_se->list, &sis->extent_list);
+ list_add_tail(&new_se->list, &sis->first_swap_extent.list);
return 1;
}
@@ -1437,7 +1442,7 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
if (S_ISBLK(inode->i_mode)) {
ret = add_swap_extent(sis, 0, sis->max, 0);
*span = sis->pages;
- goto done;
+ goto out;
}
blkbits = inode->i_blkbits;
@@ -1508,15 +1513,12 @@ reprobe:
sis->max = page_no;
sis->pages = page_no - 1;
sis->highest_bit = page_no - 1;
-done:
- sis->curr_swap_extent = list_entry(sis->extent_list.prev,
- struct swap_extent, list);
- goto out;
+out:
+ return ret;
bad_bmap:
printk(KERN_ERR "swapon: swapfile has holes\n");
ret = -EINVAL;
-out:
- return ret;
+ goto out;
}
SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
@@ -1815,7 +1817,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
kfree(p);
goto out;
}
- INIT_LIST_HEAD(&p->extent_list);
if (type >= nr_swapfiles) {
p->type = type;
swap_info[type] = p;
@@ -1834,6 +1835,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
* would be relying on p->type to remain valid.
*/
}
+ INIT_LIST_HEAD(&p->first_swap_extent.list);
p->flags = SWP_USED;
p->next = -1;
spin_unlock(&swap_lock);
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