- long incdec = value? 1: -1;
-
- entry->val = value;
- info->swapped += incdec;
- if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
- struct page *page = kmap_atomic_to_page(entry);
- set_page_private(page, page_private(page) + incdec);
- }
-}
-
-/**
- * shmem_swp_alloc - get the position of the swap entry for the page.
- * @info: info structure for the inode
- * @index: index of the page to find
- * @sgp: check and recheck i_size? skip allocation?
- * @gfp: gfp mask to use for any page allocation
- *
- * If the entry does not exist, allocate it.
- */
-static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info,
- unsigned long index, enum sgp_type sgp, gfp_t gfp)
-{
- struct inode *inode = &info->vfs_inode;
- struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
- struct page *page = NULL;
- swp_entry_t *entry;
-
- if (sgp != SGP_WRITE &&
- ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
- return ERR_PTR(-EINVAL);
-
- while (!(entry = shmem_swp_entry(info, index, &page))) {
- if (sgp == SGP_READ)
- return shmem_swp_map(ZERO_PAGE(0));
- /*
- * Test used_blocks against 1 less max_blocks, since we have 1 data
- * page (and perhaps indirect index pages) yet to allocate:
- * a waste to allocate index if we cannot allocate data.
- */
- if (sbinfo->max_blocks) {
- if (percpu_counter_compare(&sbinfo->used_blocks,
- sbinfo->max_blocks - 1) >= 0)
- return ERR_PTR(-ENOSPC);
- percpu_counter_inc(&sbinfo->used_blocks);
- inode->i_blocks += BLOCKS_PER_PAGE;
- }
-
- spin_unlock(&info->lock);
- page = shmem_dir_alloc(gfp);
- spin_lock(&info->lock);
-
- if (!page) {
- shmem_free_blocks(inode, 1);
- return ERR_PTR(-ENOMEM);
- }
- if (sgp != SGP_WRITE &&
- ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
- entry = ERR_PTR(-EINVAL);
- break;
- }
- if (info->next_index <= index)
- info->next_index = index + 1;
- }
- if (page) {
- /* another task gave its page, or truncated the file */
- shmem_free_blocks(inode, 1);
- shmem_dir_free(page);
- }
- if (info->next_index <= index && !IS_ERR(entry))
- info->next_index = index + 1;
- return entry;
-}
-
-/**
- * shmem_free_swp - free some swap entries in a directory
- * @dir: pointer to the directory
- * @edir: pointer after last entry of the directory
- * @punch_lock: pointer to spinlock when needed for the holepunch case
- */
-static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
- spinlock_t *punch_lock)
-{
- spinlock_t *punch_unlock = NULL;
- swp_entry_t *ptr;
- int freed = 0;
-
- for (ptr = dir; ptr < edir; ptr++) {
- if (ptr->val) {
- if (unlikely(punch_lock)) {
- punch_unlock = punch_lock;
- punch_lock = NULL;
- spin_lock(punch_unlock);
- if (!ptr->val)
- continue;
- }
- free_swap_and_cache(*ptr);
- *ptr = (swp_entry_t){0};
- freed++;
- }
- }
- if (punch_unlock)
- spin_unlock(punch_unlock);
- return freed;
-}
-
-static int shmem_map_and_free_swp(struct page *subdir, int offset,
- int limit, struct page ***dir, spinlock_t *punch_lock)
-{
- swp_entry_t *ptr;
- int freed = 0;
-
- ptr = shmem_swp_map(subdir);
- for (; offset < limit; offset += LATENCY_LIMIT) {
- int size = limit - offset;
- if (size > LATENCY_LIMIT)
- size = LATENCY_LIMIT;
- freed += shmem_free_swp(ptr+offset, ptr+offset+size,
- punch_lock);
- if (need_resched()) {
- shmem_swp_unmap(ptr);
- if (*dir) {
- shmem_dir_unmap(*dir);
- *dir = NULL;
- }
- cond_resched();
- ptr = shmem_swp_map(subdir);
- }
- }
- shmem_swp_unmap(ptr);
- return freed;