#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/security.h>
#include <linux/backing-dev.h>
int count;
VM_BUG_ON(!PageLocked(page));
+ if (unlikely(PageKsm(page)))
+ return 0;
count = page_mapcount(page);
if (count <= 1 && PageSwapCache(page)) {
count += page_swapcount(page);
SetPageDirty(page);
}
}
- return count == 1;
+ return count <= 1;
}
/*
goto out;
}
- inc_mm_counter(vma->vm_mm, anon_rss);
+ dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
+ inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
get_page(page);
set_pte_at(vma->vm_mm, addr, pte,
pte_mkold(mk_pte(page, vma->vm_page_prot)));
* read from disk into another page. Splitting into two
* pages would be incorrect if swap supported "shared
* private" pages, but they are handled by tmpfs files.
+ *
+ * Given how unuse_vma() targets one particular offset
+ * in an anon_vma, once the anon_vma has been determined,
+ * this splitting happens to be just what is needed to
+ * handle where KSM pages have been swapped out: re-reading
+ * is unnecessarily slow, but we can fix that later on.
*/
if (swap_count(*swap_map) &&
PageDirty(page) && PageSwapCache(page)) {
unsigned int type;
int i, prev;
int error;
- union swap_header *swap_header = NULL;
- unsigned int nr_good_pages = 0;
+ union swap_header *swap_header;
+ unsigned int nr_good_pages;
int nr_extents = 0;
sector_t span;
- unsigned long maxpages = 1;
+ unsigned long maxpages;
unsigned long swapfilepages;
unsigned char *swap_map = NULL;
struct page *page = NULL;
* swap pte.
*/
maxpages = swp_offset(pte_to_swp_entry(
- swp_entry_to_pte(swp_entry(0, ~0UL)))) - 1;
- if (maxpages > swap_header->info.last_page)
- maxpages = swap_header->info.last_page;
+ swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+ if (maxpages > swap_header->info.last_page) {
+ maxpages = swap_header->info.last_page + 1;
+ /* p->max is an unsigned int: don't overflow it */
+ if ((unsigned int)maxpages == 0)
+ maxpages = UINT_MAX;
+ }
p->highest_bit = maxpages - 1;
error = -EINVAL;
}
memset(swap_map, 0, maxpages);
+ nr_good_pages = maxpages - 1; /* omit header page */
+
for (i = 0; i < swap_header->info.nr_badpages; i++) {
- int page_nr = swap_header->info.badpages[i];
- if (page_nr <= 0 || page_nr >= swap_header->info.last_page) {
+ unsigned int page_nr = swap_header->info.badpages[i];
+ if (page_nr == 0 || page_nr > swap_header->info.last_page) {
error = -EINVAL;
goto bad_swap;
}
- swap_map[page_nr] = SWAP_MAP_BAD;
+ if (page_nr < maxpages) {
+ swap_map[page_nr] = SWAP_MAP_BAD;
+ nr_good_pages--;
+ }
}
error = swap_cgroup_swapon(type, maxpages);
if (error)
goto bad_swap;
- nr_good_pages = swap_header->info.last_page -
- swap_header->info.nr_badpages -
- 1 /* header page */;
-
if (nr_good_pages) {
swap_map[0] = SWAP_MAP_BAD;
p->max = maxpages;
}
/*
- * increase reference count of swap entry by 1.
+ * Increase reference count of swap entry by 1.
+ * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required
+ * but could not be atomically allocated. Returns 0, just as if it succeeded,
+ * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which
+ * might occur if a page table entry has got corrupted.
*/
int swap_duplicate(swp_entry_t entry)
{