atomic_t nr_rotate_swap = ATOMIC_INIT(0);
+static struct swap_info_struct *swap_type_to_swap_info(int type)
+{
+ if (type >= READ_ONCE(nr_swapfiles))
+ return NULL;
+
+ smp_rmb(); /* Pairs with smp_wmb in alloc_swap_info. */
+ return READ_ONCE(swap_info[type]);
+}
+
static inline unsigned char swap_count(unsigned char ent)
{
return ent & ~SWAP_HAS_CACHE; /* may include SWAP_HAS_CONT flag */
/* The only caller of this function is now suspend routine */
swp_entry_t get_swap_page_of_type(int type)
{
- struct swap_info_struct *si;
+ struct swap_info_struct *si = swap_type_to_swap_info(type);
pgoff_t offset;
- si = swap_info[type];
+ if (!si)
+ goto fail;
+
spin_lock(&si->lock);
- if (si && (si->flags & SWP_WRITEOK)) {
+ if (si->flags & SWP_WRITEOK) {
atomic_long_dec(&nr_swap_pages);
/* This is called for allocating swap entry, not cache */
offset = scan_swap_map(si, 1);
atomic_long_inc(&nr_swap_pages);
}
spin_unlock(&si->lock);
+fail:
return (swp_entry_t) {0};
}
if (!entry.val)
goto out;
type = swp_type(entry);
- if (type >= nr_swapfiles)
+ p = swap_type_to_swap_info(type);
+ if (!p)
goto bad_nofile;
- p = swap_info[type];
if (!(p->flags & SWP_USED))
goto bad_device;
offset = swp_offset(entry);
sector_t swapdev_block(int type, pgoff_t offset)
{
struct block_device *bdev;
+ struct swap_info_struct *si = swap_type_to_swap_info(type);
- if ((unsigned int)type >= nr_swapfiles)
- return 0;
- if (!(swap_info[type]->flags & SWP_WRITEOK))
+ if (!si || !(si->flags & SWP_WRITEOK))
return 0;
return map_swap_entry(swp_entry(type, offset), &bdev);
}
*/
if (PageSwapCache(page) &&
likely(page_private(page) == entry.val) &&
- !page_swapped(page))
+ (!PageTransCompound(page) ||
+ !swap_page_trans_huge_swapped(si, entry)))
delete_from_swap_cache(compound_head(page));
/*
struct swap_extent *se;
pgoff_t offset;
- sis = swap_info[swp_type(entry)];
+ sis = swp_swap_info(entry);
*bdev = sis->bdev;
offset = swp_offset(entry);
if (!l)
return SEQ_START_TOKEN;
- for (type = 0; type < nr_swapfiles; type++) {
- smp_rmb(); /* read nr_swapfiles before swap_info[type] */
- si = swap_info[type];
+ for (type = 0; (si = swap_type_to_swap_info(type)); type++) {
if (!(si->flags & SWP_USED) || !si->swap_map)
continue;
if (!--l)
else
type = si->type + 1;
- for (; type < nr_swapfiles; type++) {
- smp_rmb(); /* read nr_swapfiles before swap_info[type] */
- si = swap_info[type];
+ for (; (si = swap_type_to_swap_info(type)); type++) {
if (!(si->flags & SWP_USED) || !si->swap_map)
continue;
++*pos;
struct swap_info_struct *p;
unsigned int type;
int i;
+ int size = sizeof(*p) + nr_node_ids * sizeof(struct plist_node);
- p = kzalloc(sizeof(*p), GFP_KERNEL);
+ p = kvzalloc(size, GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);
}
if (type >= MAX_SWAPFILES) {
spin_unlock(&swap_lock);
- kfree(p);
+ kvfree(p);
return ERR_PTR(-EPERM);
}
if (type >= nr_swapfiles) {
p->type = type;
- swap_info[type] = p;
+ WRITE_ONCE(swap_info[type], p);
/*
* Write swap_info[type] before nr_swapfiles, in case a
* racing procfs swap_start() or swap_next() is reading them.
* (We never shrink nr_swapfiles, we never free this entry.)
*/
smp_wmb();
- nr_swapfiles++;
+ WRITE_ONCE(nr_swapfiles, nr_swapfiles + 1);
} else {
- kfree(p);
+ kvfree(p);
p = swap_info[type];
/*
* Do not memset this entry: a racing procfs swap_next()
return 0;
}
+
+/*
+ * Find out how many pages are allowed for a single swap device. There
+ * are two limiting factors:
+ * 1) the number of bits for the swap offset in the swp_entry_t type, and
+ * 2) the number of bits in the swap pte, as defined by the different
+ * architectures.
+ *
+ * In order to find the largest possible bit mask, a swap entry with
+ * swap type 0 and swap offset ~0UL is created, encoded to a swap pte,
+ * decoded to a swp_entry_t again, and finally the swap offset is
+ * extracted.
+ *
+ * This will mask all the bits from the initial ~0UL mask that can't
+ * be encoded in either the swp_entry_t or the architecture definition
+ * of a swap pte.
+ */
+unsigned long generic_max_swapfile_size(void)
+{
+ return swp_offset(pte_to_swp_entry(
+ swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+}
+
+/* Can be overridden by an architecture for additional checks. */
+__weak unsigned long max_swapfile_size(void)
+{
+ return generic_max_swapfile_size();
+}
+
static unsigned long read_swap_header(struct swap_info_struct *p,
union swap_header *swap_header,
struct inode *inode)
p->cluster_next = 1;
p->cluster_nr = 0;
- /*
- * Find out how many pages are allowed for a single swap
- * device. There are two limiting factors: 1) the number
- * of bits for the swap offset in the swp_entry_t type, and
- * 2) the number of bits in the swap pte as defined by the
- * different architectures. In order to find the
- * largest possible bit mask, a swap entry with swap type 0
- * and swap offset ~0UL is created, encoded to a swap pte,
- * decoded to a swp_entry_t again, and finally the swap
- * offset is extracted. This will mask all the bits from
- * the initial ~0UL mask that can't be encoded in either
- * the swp_entry_t or the architecture definition of a
- * swap pte.
- */
- maxpages = swp_offset(pte_to_swp_entry(
- swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+ maxpages = max_swapfile_size();
last_page = swap_header->info.last_page;
+ if (!last_page) {
+ pr_warn("Empty swap-file\n");
+ return 0;
+ }
if (last_page > maxpages) {
pr_warn("Truncating oversized swap area, only using %luk out of %luk\n",
maxpages << (PAGE_SHIFT - 10),
{
struct swap_info_struct *p;
struct swap_cluster_info *ci;
- unsigned long offset, type;
+ unsigned long offset;
unsigned char count;
unsigned char has_cache;
int err = -EINVAL;
if (non_swap_entry(entry))
goto out;
- type = swp_type(entry);
- if (type >= nr_swapfiles)
+ p = swp_swap_info(entry);
+ if (!p)
goto bad_file;
- p = swap_info[type];
+
offset = swp_offset(entry);
if (unlikely(offset >= p->max))
goto out;
struct swap_info_struct *swp_swap_info(swp_entry_t entry)
{
- return swap_info[swp_type(entry)];
+ return swap_type_to_swap_info(swp_type(entry));
}
struct swap_info_struct *page_swap_info(struct page *page)
projects / mirror_ubuntu-bionic-kernel.git / blobdiff