| /* |
| * linux/mm/swapfile.c |
| * |
| * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| * Swap reorganised 29.12.95, Stephen Tweedie |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/mm.h> |
| #include <linux/hugetlb.h> |
| #include <linux/mman.h> |
| #include <linux/slab.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/swap.h> |
| #include <linux/vmalloc.h> |
| #include <linux/pagemap.h> |
| #include <linux/namei.h> |
| #include <linux/shm.h> |
| #include <linux/blkdev.h> |
| #include <linux/writeback.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/rmap.h> |
| #include <linux/security.h> |
| #include <linux/backing-dev.h> |
| #include <linux/syscalls.h> |
| |
| #include <asm/pgtable.h> |
| #include <asm/tlbflush.h> |
| #include <linux/swapops.h> |
| |
| DEFINE_SPINLOCK(swaplock); |
| unsigned int nr_swapfiles; |
| long total_swap_pages; |
| static int swap_overflow; |
| |
| EXPORT_SYMBOL(total_swap_pages); |
| |
| static const char Bad_file[] = "Bad swap file entry "; |
| static const char Unused_file[] = "Unused swap file entry "; |
| static const char Bad_offset[] = "Bad swap offset entry "; |
| static const char Unused_offset[] = "Unused swap offset entry "; |
| |
| struct swap_list_t swap_list = {-1, -1}; |
| |
| struct swap_info_struct swap_info[MAX_SWAPFILES]; |
| |
| static DECLARE_MUTEX(swapon_sem); |
| |
| /* |
| * We need this because the bdev->unplug_fn can sleep and we cannot |
| * hold swap_list_lock while calling the unplug_fn. And swap_list_lock |
| * cannot be turned into a semaphore. |
| */ |
| static DECLARE_RWSEM(swap_unplug_sem); |
| |
| #define SWAPFILE_CLUSTER 256 |
| |
| void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page) |
| { |
| swp_entry_t entry; |
| |
| down_read(&swap_unplug_sem); |
| entry.val = page->private; |
| if (PageSwapCache(page)) { |
| struct block_device *bdev = swap_info[swp_type(entry)].bdev; |
| struct backing_dev_info *bdi; |
| |
| /* |
| * If the page is removed from swapcache from under us (with a |
| * racy try_to_unuse/swapoff) we need an additional reference |
| * count to avoid reading garbage from page->private above. If |
| * the WARN_ON triggers during a swapoff it maybe the race |
| * condition and it's harmless. However if it triggers without |
| * swapoff it signals a problem. |
| */ |
| WARN_ON(page_count(page) <= 1); |
| |
| bdi = bdev->bd_inode->i_mapping->backing_dev_info; |
| blk_run_backing_dev(bdi, page); |
| } |
| up_read(&swap_unplug_sem); |
| } |
| |
| static inline int scan_swap_map(struct swap_info_struct *si) |
| { |
| unsigned long offset; |
| /* |
| * We try to cluster swap pages by allocating them |
| * sequentially in swap. Once we've allocated |
| * SWAPFILE_CLUSTER pages this way, however, we resort to |
| * first-free allocation, starting a new cluster. This |
| * prevents us from scattering swap pages all over the entire |
| * swap partition, so that we reduce overall disk seek times |
| * between swap pages. -- sct */ |
| if (si->cluster_nr) { |
| while (si->cluster_next <= si->highest_bit) { |
| offset = si->cluster_next++; |
| if (si->swap_map[offset]) |
| continue; |
| si->cluster_nr--; |
| goto got_page; |
| } |
| } |
| si->cluster_nr = SWAPFILE_CLUSTER; |
| |
| /* try to find an empty (even not aligned) cluster. */ |
| offset = si->lowest_bit; |
| check_next_cluster: |
| if (offset+SWAPFILE_CLUSTER-1 <= si->highest_bit) |
| { |
| unsigned long nr; |
| for (nr = offset; nr < offset+SWAPFILE_CLUSTER; nr++) |
| if (si->swap_map[nr]) |
| { |
| offset = nr+1; |
| goto check_next_cluster; |
| } |
| /* We found a completly empty cluster, so start |
| * using it. |
| */ |
| goto got_page; |
| } |
| /* No luck, so now go finegrined as usual. -Andrea */ |
| for (offset = si->lowest_bit; offset <= si->highest_bit ; offset++) { |
| if (si->swap_map[offset]) |
| continue; |
| si->lowest_bit = offset+1; |
| got_page: |
| if (offset == si->lowest_bit) |
| si->lowest_bit++; |
| if (offset == si->highest_bit) |
| si->highest_bit--; |
| if (si->lowest_bit > si->highest_bit) { |
| si->lowest_bit = si->max; |
| si->highest_bit = 0; |
| } |
| si->swap_map[offset] = 1; |
| si->inuse_pages++; |
| nr_swap_pages--; |
| si->cluster_next = offset+1; |
| return offset; |
| } |
| si->lowest_bit = si->max; |
| si->highest_bit = 0; |
| return 0; |
| } |
| |
| swp_entry_t get_swap_page(void) |
| { |
| struct swap_info_struct * p; |
| unsigned long offset; |
| swp_entry_t entry; |
| int type, wrapped = 0; |
| |
| entry.val = 0; /* Out of memory */ |
| swap_list_lock(); |
| type = swap_list.next; |
| if (type < 0) |
| goto out; |
| if (nr_swap_pages <= 0) |
| goto out; |
| |
| while (1) { |
| p = &swap_info[type]; |
| if ((p->flags & SWP_ACTIVE) == SWP_ACTIVE) { |
| swap_device_lock(p); |
| offset = scan_swap_map(p); |
| swap_device_unlock(p); |
| if (offset) { |
| entry = swp_entry(type,offset); |
| type = swap_info[type].next; |
| if (type < 0 || |
| p->prio != swap_info[type].prio) { |
| swap_list.next = swap_list.head; |
| } else { |
| swap_list.next = type; |
| } |
| goto out; |
| } |
| } |
| type = p->next; |
| if (!wrapped) { |
| if (type < 0 || p->prio != swap_info[type].prio) { |
| type = swap_list.head; |
| wrapped = 1; |
| } |
| } else |
| if (type < 0) |
| goto out; /* out of swap space */ |
| } |
| out: |
| swap_list_unlock(); |
| return entry; |
| } |
| |
| static struct swap_info_struct * swap_info_get(swp_entry_t entry) |
| { |
| struct swap_info_struct * p; |
| unsigned long offset, type; |
| |
| if (!entry.val) |
| goto out; |
| type = swp_type(entry); |
| if (type >= nr_swapfiles) |
| goto bad_nofile; |
| p = & swap_info[type]; |
| if (!(p->flags & SWP_USED)) |
| goto bad_device; |
| offset = swp_offset(entry); |
| if (offset >= p->max) |
| goto bad_offset; |
| if (!p->swap_map[offset]) |
| goto bad_free; |
| swap_list_lock(); |
| if (p->prio > swap_info[swap_list.next].prio) |
| swap_list.next = type; |
| swap_device_lock(p); |
| return p; |
| |
| bad_free: |
| printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val); |
| goto out; |
| bad_offset: |
| printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val); |
| goto out; |
| bad_device: |
| printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val); |
| goto out; |
| bad_nofile: |
| printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val); |
| out: |
| return NULL; |
| } |
| |
| static void swap_info_put(struct swap_info_struct * p) |
| { |
| swap_device_unlock(p); |
| swap_list_unlock(); |
| } |
| |
| static int swap_entry_free(struct swap_info_struct *p, unsigned long offset) |
| { |
| int count = p->swap_map[offset]; |
| |
| if (count < SWAP_MAP_MAX) { |
| count--; |
| p->swap_map[offset] = count; |
| if (!count) { |
| if (offset < p->lowest_bit) |
| p->lowest_bit = offset; |
| if (offset > p->highest_bit) |
| p->highest_bit = offset; |
| nr_swap_pages++; |
| p->inuse_pages--; |
| } |
| } |
| return count; |
| } |
| |
| /* |
| * Caller has made sure that the swapdevice corresponding to entry |
| * is still around or has not been recycled. |
| */ |
| void swap_free(swp_entry_t entry) |
| { |
| struct swap_info_struct * p; |
| |
| p = swap_info_get(entry); |
| if (p) { |
| swap_entry_free(p, swp_offset(entry)); |
| swap_info_put(p); |
| } |
| } |
| |
| /* |
| * How many references to page are currently swapped out? |
| */ |
| static inline int page_swapcount(struct page *page) |
| { |
| int count = 0; |
| struct swap_info_struct *p; |
| swp_entry_t entry; |
| |
| entry.val = page->private; |
| p = swap_info_get(entry); |
| if (p) { |
| /* Subtract the 1 for the swap cache itself */ |
| count = p->swap_map[swp_offset(entry)] - 1; |
| swap_info_put(p); |
| } |
| return count; |
| } |
| |
| /* |
| * We can use this swap cache entry directly |
| * if there are no other references to it. |
| */ |
| int can_share_swap_page(struct page *page) |
| { |
| int count; |
| |
| BUG_ON(!PageLocked(page)); |
| count = page_mapcount(page); |
| if (count <= 1 && PageSwapCache(page)) |
| count += page_swapcount(page); |
| return count == 1; |
| } |
| |
| /* |
| * Work out if there are any other processes sharing this |
| * swap cache page. Free it if you can. Return success. |
| */ |
| int remove_exclusive_swap_page(struct page *page) |
| { |
| int retval; |
| struct swap_info_struct * p; |
| swp_entry_t entry; |
| |
| BUG_ON(PagePrivate(page)); |
| BUG_ON(!PageLocked(page)); |
| |
| if (!PageSwapCache(page)) |
| return 0; |
| if (PageWriteback(page)) |
| return 0; |
| if (page_count(page) != 2) /* 2: us + cache */ |
| return 0; |
| |
| entry.val = page->private; |
| p = swap_info_get(entry); |
| if (!p) |
| return 0; |
| |
| /* Is the only swap cache user the cache itself? */ |
| retval = 0; |
| if (p->swap_map[swp_offset(entry)] == 1) { |
| /* Recheck the page count with the swapcache lock held.. */ |
| write_lock_irq(&swapper_space.tree_lock); |
| if ((page_count(page) == 2) && !PageWriteback(page)) { |
| __delete_from_swap_cache(page); |
| SetPageDirty(page); |
| retval = 1; |
| } |
| write_unlock_irq(&swapper_space.tree_lock); |
| } |
| swap_info_put(p); |
| |
| if (retval) { |
| swap_free(entry); |
| page_cache_release(page); |
| } |
| |
| return retval; |
| } |
| |
| /* |
| * Free the swap entry like above, but also try to |
| * free the page cache entry if it is the last user. |
| */ |
| void free_swap_and_cache(swp_entry_t entry) |
| { |
| struct swap_info_struct * p; |
| struct page *page = NULL; |
| |
| p = swap_info_get(entry); |
| if (p) { |
| if (swap_entry_free(p, swp_offset(entry)) == 1) |
| page = find_trylock_page(&swapper_space, entry.val); |
| swap_info_put(p); |
| } |
| if (page) { |
| int one_user; |
| |
| BUG_ON(PagePrivate(page)); |
| page_cache_get(page); |
| one_user = (page_count(page) == 2); |
| /* Only cache user (+us), or swap space full? Free it! */ |
| if (!PageWriteback(page) && (one_user || vm_swap_full())) { |
| delete_from_swap_cache(page); |
| SetPageDirty(page); |
| } |
| unlock_page(page); |
| page_cache_release(page); |
| } |
| } |
| |
| /* |
| * Always set the resulting pte to be nowrite (the same as COW pages |
| * after one process has exited). We don't know just how many PTEs will |
| * share this swap entry, so be cautious and let do_wp_page work out |
| * what to do if a write is requested later. |
| * |
| * vma->vm_mm->page_table_lock is held. |
| */ |
| static void unuse_pte(struct vm_area_struct *vma, pte_t *pte, |
| unsigned long addr, swp_entry_t entry, struct page *page) |
| { |
| inc_mm_counter(vma->vm_mm, rss); |
| get_page(page); |
| set_pte_at(vma->vm_mm, addr, pte, |
| pte_mkold(mk_pte(page, vma->vm_page_prot))); |
| page_add_anon_rmap(page, vma, addr); |
| swap_free(entry); |
| /* |
| * Move the page to the active list so it is not |
| * immediately swapped out again after swapon. |
| */ |
| activate_page(page); |
| } |
| |
| static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
| unsigned long addr, unsigned long end, |
| swp_entry_t entry, struct page *page) |
| { |
| pte_t *pte; |
| pte_t swp_pte = swp_entry_to_pte(entry); |
| |
| pte = pte_offset_map(pmd, addr); |
| do { |
| /* |
| * swapoff spends a _lot_ of time in this loop! |
| * Test inline before going to call unuse_pte. |
| */ |
| if (unlikely(pte_same(*pte, swp_pte))) { |
| unuse_pte(vma, pte, addr, entry, page); |
| pte_unmap(pte); |
| return 1; |
| } |
| } while (pte++, addr += PAGE_SIZE, addr != end); |
| pte_unmap(pte - 1); |
| return 0; |
| } |
| |
| static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, |
| unsigned long addr, unsigned long end, |
| swp_entry_t entry, struct page *page) |
| { |
| pmd_t *pmd; |
| unsigned long next; |
| |
| pmd = pmd_offset(pud, addr); |
| do { |
| next = pmd_addr_end(addr, end); |
| if (pmd_none_or_clear_bad(pmd)) |
| continue; |
| if (unuse_pte_range(vma, pmd, addr, next, entry, page)) |
| return 1; |
| } while (pmd++, addr = next, addr != end); |
| return 0; |
| } |
| |
| static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, |
| unsigned long addr, unsigned long end, |
| swp_entry_t entry, struct page *page) |
| { |
| pud_t *pud; |
| unsigned long next; |
| |
| pud = pud_offset(pgd, addr); |
| do { |
| next = pud_addr_end(addr, end); |
| if (pud_none_or_clear_bad(pud)) |
| continue; |
| if (unuse_pmd_range(vma, pud, addr, next, entry, page)) |
| return 1; |
| } while (pud++, addr = next, addr != end); |
| return 0; |
| } |
| |
| static int unuse_vma(struct vm_area_struct *vma, |
| swp_entry_t entry, struct page *page) |
| { |
| pgd_t *pgd; |
| unsigned long addr, end, next; |
| |
| if (page->mapping) { |
| addr = page_address_in_vma(page, vma); |
| if (addr == -EFAULT) |
| return 0; |
| else |
| end = addr + PAGE_SIZE; |
| } else { |
| addr = vma->vm_start; |
| end = vma->vm_end; |
| } |
| |
| pgd = pgd_offset(vma->vm_mm, addr); |
| do { |
| next = pgd_addr_end(addr, end); |
| if (pgd_none_or_clear_bad(pgd)) |
| continue; |
| if (unuse_pud_range(vma, pgd, addr, next, entry, page)) |
| return 1; |
| } while (pgd++, addr = next, addr != end); |
| return 0; |
| } |
| |
| static int unuse_mm(struct mm_struct *mm, |
| swp_entry_t entry, struct page *page) |
| { |
| struct vm_area_struct *vma; |
| |
| if (!down_read_trylock(&mm->mmap_sem)) { |
| /* |
| * Activate page so shrink_cache is unlikely to unmap its |
| * ptes while lock is dropped, so swapoff can make progress. |
| */ |
| activate_page(page); |
| unlock_page(page); |
| down_read(&mm->mmap_sem); |
| lock_page(page); |
| } |
| spin_lock(&mm->page_table_lock); |
| for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| if (vma->anon_vma && unuse_vma(vma, entry, page)) |
| break; |
| } |
| spin_unlock(&mm->page_table_lock); |
| up_read(&mm->mmap_sem); |
| /* |
| * Currently unuse_mm cannot fail, but leave error handling |
| * at call sites for now, since we change it from time to time. |
| */ |
| return 0; |
| } |
| |
| /* |
| * Scan swap_map from current position to next entry still in use. |
| * Recycle to start on reaching the end, returning 0 when empty. |
| */ |
| static int find_next_to_unuse(struct swap_info_struct *si, int prev) |
| { |
| int max = si->max; |
| int i = prev; |
| int count; |
| |
| /* |
| * No need for swap_device_lock(si) here: we're just looking |
| * for whether an entry is in use, not modifying it; false |
| * hits are okay, and sys_swapoff() has already prevented new |
| * allocations from this area (while holding swap_list_lock()). |
| */ |
| for (;;) { |
| if (++i >= max) { |
| if (!prev) { |
| i = 0; |
| break; |
| } |
| /* |
| * No entries in use at top of swap_map, |
| * loop back to start and recheck there. |
| */ |
| max = prev + 1; |
| prev = 0; |
| i = 1; |
| } |
| count = si->swap_map[i]; |
| if (count && count != SWAP_MAP_BAD) |
| break; |
| } |
| return i; |
| } |
| |
| /* |
| * We completely avoid races by reading each swap page in advance, |
| * and then search for the process using it. All the necessary |
| * page table adjustments can then be made atomically. |
| */ |
| static int try_to_unuse(unsigned int type) |
| { |
| struct swap_info_struct * si = &swap_info[type]; |
| struct mm_struct *start_mm; |
| unsigned short *swap_map; |
| unsigned short swcount; |
| struct page *page; |
| swp_entry_t entry; |
| int i = 0; |
| int retval = 0; |
| int reset_overflow = 0; |
| int shmem; |
| |
| /* |
| * When searching mms for an entry, a good strategy is to |
| * start at the first mm we freed the previous entry from |
| * (though actually we don't notice whether we or coincidence |
| * freed the entry). Initialize this start_mm with a hold. |
| * |
| * A simpler strategy would be to start at the last mm we |
| * freed the previous entry from; but that would take less |
| * advantage of mmlist ordering, which clusters forked mms |
| * together, child after parent. If we race with dup_mmap(), we |
| * prefer to resolve parent before child, lest we miss entries |
| * duplicated after we scanned child: using last mm would invert |
| * that. Though it's only a serious concern when an overflowed |
| * swap count is reset from SWAP_MAP_MAX, preventing a rescan. |
| */ |
| start_mm = &init_mm; |
| atomic_inc(&init_mm.mm_users); |
| |
| /* |
| * Keep on scanning until all entries have gone. Usually, |
| * one pass through swap_map is enough, but not necessarily: |
| * there are races when an instance of an entry might be missed. |
| */ |
| while ((i = find_next_to_unuse(si, i)) != 0) { |
| if (signal_pending(current)) { |
| retval = -EINTR; |
| break; |
| } |
| |
| /* |
| * Get a page for the entry, using the existing swap |
| * cache page if there is one. Otherwise, get a clean |
| * page and read the swap into it. |
| */ |
| swap_map = &si->swap_map[i]; |
| entry = swp_entry(type, i); |
| page = read_swap_cache_async(entry, NULL, 0); |
| if (!page) { |
| /* |
| * Either swap_duplicate() failed because entry |
| * has been freed independently, and will not be |
| * reused since sys_swapoff() already disabled |
| * allocation from here, or alloc_page() failed. |
| */ |
| if (!*swap_map) |
| continue; |
| retval = -ENOMEM; |
| break; |
| } |
| |
| /* |
| * Don't hold on to start_mm if it looks like exiting. |
| */ |
| if (atomic_read(&start_mm->mm_users) == 1) { |
| mmput(start_mm); |
| start_mm = &init_mm; |
| atomic_inc(&init_mm.mm_users); |
| } |
| |
| /* |
| * Wait for and lock page. When do_swap_page races with |
| * try_to_unuse, do_swap_page can handle the fault much |
| * faster than try_to_unuse can locate the entry. This |
| * apparently redundant "wait_on_page_locked" lets try_to_unuse |
| * defer to do_swap_page in such a case - in some tests, |
| * do_swap_page and try_to_unuse repeatedly compete. |
| */ |
| wait_on_page_locked(page); |
| wait_on_page_writeback(page); |
| lock_page(page); |
| wait_on_page_writeback(page); |
| |
| /* |
| * Remove all references to entry. |
| * Whenever we reach init_mm, there's no address space |
| * to search, but use it as a reminder to search shmem. |
| */ |
| shmem = 0; |
| swcount = *swap_map; |
| if (swcount > 1) { |
| if (start_mm == &init_mm) |
| shmem = shmem_unuse(entry, page); |
| else |
| retval = unuse_mm(start_mm, entry, page); |
| } |
| if (*swap_map > 1) { |
| int set_start_mm = (*swap_map >= swcount); |
| struct list_head *p = &start_mm->mmlist; |
| struct mm_struct *new_start_mm = start_mm; |
| struct mm_struct *prev_mm = start_mm; |
| struct mm_struct *mm; |
| |
| atomic_inc(&new_start_mm->mm_users); |
| atomic_inc(&prev_mm->mm_users); |
| spin_lock(&mmlist_lock); |
| while (*swap_map > 1 && !retval && |
| (p = p->next) != &start_mm->mmlist) { |
| mm = list_entry(p, struct mm_struct, mmlist); |
| if (atomic_inc_return(&mm->mm_users) == 1) { |
| atomic_dec(&mm->mm_users); |
| continue; |
| } |
| spin_unlock(&mmlist_lock); |
| mmput(prev_mm); |
| prev_mm = mm; |
| |
| cond_resched(); |
| |
| swcount = *swap_map; |
| if (swcount <= 1) |
| ; |
| else if (mm == &init_mm) { |
| set_start_mm = 1; |
| shmem = shmem_unuse(entry, page); |
| } else |
| retval = unuse_mm(mm, entry, page); |
| if (set_start_mm && *swap_map < swcount) { |
| mmput(new_start_mm); |
| atomic_inc(&mm->mm_users); |
| new_start_mm = mm; |
| set_start_mm = 0; |
| } |
| spin_lock(&mmlist_lock); |
| } |
| spin_unlock(&mmlist_lock); |
| mmput(prev_mm); |
| mmput(start_mm); |
| start_mm = new_start_mm; |
| } |
| if (retval) { |
| unlock_page(page); |
| page_cache_release(page); |
| break; |
| } |
| |
| /* |
| * How could swap count reach 0x7fff when the maximum |
| * pid is 0x7fff, and there's no way to repeat a swap |
| * page within an mm (except in shmem, where it's the |
| * shared object which takes the reference count)? |
| * We believe SWAP_MAP_MAX cannot occur in Linux 2.4. |
| * |
| * If that's wrong, then we should worry more about |
| * exit_mmap() and do_munmap() cases described above: |
| * we might be resetting SWAP_MAP_MAX too early here. |
| * We know "Undead"s can happen, they're okay, so don't |
| * report them; but do report if we reset SWAP_MAP_MAX. |
| */ |
| if (*swap_map == SWAP_MAP_MAX) { |
| swap_device_lock(si); |
| *swap_map = 1; |
| swap_device_unlock(si); |
| reset_overflow = 1; |
| } |
| |
| /* |
| * If a reference remains (rare), we would like to leave |
| * the page in the swap cache; but try_to_unmap could |
| * then re-duplicate the entry once we drop page lock, |
| * so we might loop indefinitely; also, that page could |
| * not be swapped out to other storage meanwhile. So: |
| * delete from cache even if there's another reference, |
| * after ensuring that the data has been saved to disk - |
| * since if the reference remains (rarer), it will be |
| * 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. |
| * |
| * Note shmem_unuse already deleted a swappage from |
| * the swap cache, unless the move to filepage failed: |
| * in which case it left swappage in cache, lowered its |
| * swap count to pass quickly through the loops above, |
| * and now we must reincrement count to try again later. |
| */ |
| if ((*swap_map > 1) && PageDirty(page) && PageSwapCache(page)) { |
| struct writeback_control wbc = { |
| .sync_mode = WB_SYNC_NONE, |
| }; |
| |
| swap_writepage(page, &wbc); |
| lock_page(page); |
| wait_on_page_writeback(page); |
| } |
| if (PageSwapCache(page)) { |
| if (shmem) |
| swap_duplicate(entry); |
| else |
| delete_from_swap_cache(page); |
| } |
| |
| /* |
| * So we could skip searching mms once swap count went |
| * to 1, we did not mark any present ptes as dirty: must |
| * mark page dirty so shrink_list will preserve it. |
| */ |
| SetPageDirty(page); |
| unlock_page(page); |
| page_cache_release(page); |
| |
| /* |
| * Make sure that we aren't completely killing |
| * interactive performance. |
| */ |
| cond_resched(); |
| } |
| |
| mmput(start_mm); |
| if (reset_overflow) { |
| printk(KERN_WARNING "swapoff: cleared swap entry overflow\n"); |
| swap_overflow = 0; |
| } |
| return retval; |
| } |
| |
| /* |
| * After a successful try_to_unuse, if no swap is now in use, we know we |
| * can empty the mmlist. swap_list_lock must be held on entry and exit. |
| * Note that mmlist_lock nests inside swap_list_lock, and an mm must be |
| * added to the mmlist just after page_duplicate - before would be racy. |
| */ |
| static void drain_mmlist(void) |
| { |
| struct list_head *p, *next; |
| unsigned int i; |
| |
| for (i = 0; i < nr_swapfiles; i++) |
| if (swap_info[i].inuse_pages) |
| return; |
| spin_lock(&mmlist_lock); |
| list_for_each_safe(p, next, &init_mm.mmlist) |
| list_del_init(p); |
| spin_unlock(&mmlist_lock); |
| } |
| |
| /* |
| * Use this swapdev's extent info to locate the (PAGE_SIZE) block which |
| * corresponds to page offset `offset'. |
| */ |
| sector_t map_swap_page(struct swap_info_struct *sis, pgoff_t offset) |
| { |
| struct swap_extent *se = sis->curr_swap_extent; |
| struct swap_extent *start_se = se; |
| |
| for ( ; ; ) { |
| struct list_head *lh; |
| |
| if (se->start_page <= offset && |
| offset < (se->start_page + se->nr_pages)) { |
| return se->start_block + (offset - se->start_page); |
| } |
| lh = se->list.prev; |
| if (lh == &sis->extent_list) |
| lh = lh->prev; |
| se = list_entry(lh, struct swap_extent, list); |
| sis->curr_swap_extent = se; |
| BUG_ON(se == start_se); /* It *must* be present */ |
| } |
| } |
| |
| /* |
| * Free all of a swapdev's extent information |
| */ |
| static void destroy_swap_extents(struct swap_info_struct *sis) |
| { |
| while (!list_empty(&sis->extent_list)) { |
| struct swap_extent *se; |
| |
| se = list_entry(sis->extent_list.next, |
| struct swap_extent, list); |
| list_del(&se->list); |
| kfree(se); |
| } |
| sis->nr_extents = 0; |
| } |
| |
| /* |
| * Add a block range (and the corresponding page range) into this swapdev's |
| * extent list. The extent list is kept sorted in block order. |
| * |
| * This function rather assumes that it is called in ascending sector_t order. |
| * It doesn't look for extent coalescing opportunities. |
| */ |
| static int |
| add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, |
| unsigned long nr_pages, sector_t start_block) |
| { |
| struct swap_extent *se; |
| struct swap_extent *new_se; |
| struct list_head *lh; |
| |
| lh = sis->extent_list.next; /* The highest-addressed block */ |
| while (lh != &sis->extent_list) { |
| se = list_entry(lh, struct swap_extent, list); |
| if (se->start_block + se->nr_pages == start_block && |
| se->start_page + se->nr_pages == start_page) { |
| /* Merge it */ |
| se->nr_pages += nr_pages; |
| return 0; |
| } |
| lh = lh->next; |
| } |
| |
| /* |
| * No merge. Insert a new extent, preserving ordering. |
| */ |
| new_se = kmalloc(sizeof(*se), GFP_KERNEL); |
| if (new_se == NULL) |
| return -ENOMEM; |
| new_se->start_page = start_page; |
| new_se->nr_pages = nr_pages; |
| new_se->start_block = start_block; |
| |
| lh = sis->extent_list.prev; /* The lowest block */ |
| while (lh != &sis->extent_list) { |
| se = list_entry(lh, struct swap_extent, list); |
| if (se->start_block > start_block) |
| break; |
| lh = lh->prev; |
| } |
| list_add_tail(&new_se->list, lh); |
| sis->nr_extents++; |
| return 0; |
| } |
| |
| /* |
| * A `swap extent' is a simple thing which maps a contiguous range of pages |
| * onto a contiguous range of disk blocks. An ordered list of swap extents |
| * is built at swapon time and is then used at swap_writepage/swap_readpage |
| * time for locating where on disk a page belongs. |
| * |
| * If the swapfile is an S_ISBLK block device, a single extent is installed. |
| * This is done so that the main operating code can treat S_ISBLK and S_ISREG |
| * swap files identically. |
| * |
| * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap |
| * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK |
| * swapfiles are handled *identically* after swapon time. |
| * |
| * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks |
| * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If |
| * some stray blocks are found which do not fall within the PAGE_SIZE alignment |
| * requirements, they are simply tossed out - we will never use those blocks |
| * for swapping. |
| * |
| * For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
| * prevents root from shooting her foot off by ftruncating an in-use swapfile, |
| * which will scribble on the fs. |
| * |
| * The amount of disk space which a single swap extent represents varies. |
| * Typically it is in the 1-4 megabyte range. So we can have hundreds of |
| * extents in the list. To avoid much list walking, we cache the previous |
| * search location in `curr_swap_extent', and start new searches from there. |
| * This is extremely effective. The average number of iterations in |
| * map_swap_page() has been measured at about 0.3 per page. - akpm. |
| */ |
| static int setup_swap_extents(struct swap_info_struct *sis) |
| { |
| struct inode *inode; |
| unsigned blocks_per_page; |
| unsigned long page_no; |
| unsigned blkbits; |
| sector_t probe_block; |
| sector_t last_block; |
| int ret; |
| |
| inode = sis->swap_file->f_mapping->host; |
| if (S_ISBLK(inode->i_mode)) { |
| ret = add_swap_extent(sis, 0, sis->max, 0); |
| goto done; |
| } |
| |
| blkbits = inode->i_blkbits; |
| blocks_per_page = PAGE_SIZE >> blkbits; |
| |
| /* |
| * Map all the blocks into the extent list. This code doesn't try |
| * to be very smart. |
| */ |
| probe_block = 0; |
| page_no = 0; |
| last_block = i_size_read(inode) >> blkbits; |
| while ((probe_block + blocks_per_page) <= last_block && |
| page_no < sis->max) { |
| unsigned block_in_page; |
| sector_t first_block; |
| |
| first_block = bmap(inode, probe_block); |
| if (first_block == 0) |
| goto bad_bmap; |
| |
| /* |
| * It must be PAGE_SIZE aligned on-disk |
| */ |
| if (first_block & (blocks_per_page - 1)) { |
| probe_block++; |
| goto reprobe; |
| } |
| |
| for (block_in_page = 1; block_in_page < blocks_per_page; |
| block_in_page++) { |
| sector_t block; |
| |
| block = bmap(inode, probe_block + block_in_page); |
| if (block == 0) |
| goto bad_bmap; |
| if (block != first_block + block_in_page) { |
| /* Discontiguity */ |
| probe_block++; |
| goto reprobe; |
| } |
| } |
| |
| /* |
| * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks |
| */ |
| ret = add_swap_extent(sis, page_no, 1, |
| first_block >> (PAGE_SHIFT - blkbits)); |
| if (ret) |
| goto out; |
| page_no++; |
| probe_block += blocks_per_page; |
| reprobe: |
| continue; |
| } |
| ret = 0; |
| if (page_no == 0) |
| ret = -EINVAL; |
| sis->max = page_no; |
| sis->highest_bit = page_no - 1; |
| done: |
| sis->curr_swap_extent = list_entry(sis->extent_list.prev, |
| struct swap_extent, list); |
| goto out; |
| bad_bmap: |
| printk(KERN_ERR "swapon: swapfile has holes\n"); |
| ret = -EINVAL; |
| out: |
| return ret; |
| } |
| |
| #if 0 /* We don't need this yet */ |
| #include <linux/backing-dev.h> |
| int page_queue_congested(struct page *page) |
| { |
| struct backing_dev_info *bdi; |
| |
| BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ |
| |
| if (PageSwapCache(page)) { |
| swp_entry_t entry = { .val = page->private }; |
| struct swap_info_struct *sis; |
| |
| sis = get_swap_info_struct(swp_type(entry)); |
| bdi = sis->bdev->bd_inode->i_mapping->backing_dev_info; |
| } else |
| bdi = page->mapping->backing_dev_info; |
| return bdi_write_congested(bdi); |
| } |
| #endif |
| |
| asmlinkage long sys_swapoff(const char __user * specialfile) |
| { |
| struct swap_info_struct * p = NULL; |
| unsigned short *swap_map; |
| struct file *swap_file, *victim; |
| struct address_space *mapping; |
| struct inode *inode; |
| char * pathname; |
| int i, type, prev; |
| int err; |
| |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| |
| pathname = getname(specialfile); |
| err = PTR_ERR(pathname); |
| if (IS_ERR(pathname)) |
| goto out; |
| |
| victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); |
| putname(pathname); |
| err = PTR_ERR(victim); |
| if (IS_ERR(victim)) |
| goto out; |
| |
| mapping = victim->f_mapping; |
| prev = -1; |
| swap_list_lock(); |
| for (type = swap_list.head; type >= 0; type = swap_info[type].next) { |
| p = swap_info + type; |
| if ((p->flags & SWP_ACTIVE) == SWP_ACTIVE) { |
| if (p->swap_file->f_mapping == mapping) |
| break; |
| } |
| prev = type; |
| } |
| if (type < 0) { |
| err = -EINVAL; |
| swap_list_unlock(); |
| goto out_dput; |
| } |
| if (!security_vm_enough_memory(p->pages)) |
| vm_unacct_memory(p->pages); |
| else { |
| err = -ENOMEM; |
| swap_list_unlock(); |
| goto out_dput; |
| } |
| if (prev < 0) { |
| swap_list.head = p->next; |
| } else { |
| swap_info[prev].next = p->next; |
| } |
| if (type == swap_list.next) { |
| /* just pick something that's safe... */ |
| swap_list.next = swap_list.head; |
| } |
| nr_swap_pages -= p->pages; |
| total_swap_pages -= p->pages; |
| p->flags &= ~SWP_WRITEOK; |
| swap_list_unlock(); |
| current->flags |= PF_SWAPOFF; |
| err = try_to_unuse(type); |
| current->flags &= ~PF_SWAPOFF; |
| |
| /* wait for any unplug function to finish */ |
| down_write(&swap_unplug_sem); |
| up_write(&swap_unplug_sem); |
| |
| if (err) { |
| /* re-insert swap space back into swap_list */ |
| swap_list_lock(); |
| for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next) |
| if (p->prio >= swap_info[i].prio) |
| break; |
| p->next = i; |
| if (prev < 0) |
| swap_list.head = swap_list.next = p - swap_info; |
| else |
| swap_info[prev].next = p - swap_info; |
| nr_swap_pages += p->pages; |
| total_swap_pages += p->pages; |
| p->flags |= SWP_WRITEOK; |
| swap_list_unlock(); |
| goto out_dput; |
| } |
| down(&swapon_sem); |
| swap_list_lock(); |
| drain_mmlist(); |
| swap_device_lock(p); |
| swap_file = p->swap_file; |
| p->swap_file = NULL; |
| p->max = 0; |
| swap_map = p->swap_map; |
| p->swap_map = NULL; |
| p->flags = 0; |
| destroy_swap_extents(p); |
| swap_device_unlock(p); |
| swap_list_unlock(); |
| up(&swapon_sem); |
| vfree(swap_map); |
| inode = mapping->host; |
| if (S_ISBLK(inode->i_mode)) { |
| struct block_device *bdev = I_BDEV(inode); |
| set_blocksize(bdev, p->old_block_size); |
| bd_release(bdev); |
| } else { |
| down(&inode->i_sem); |
| inode->i_flags &= ~S_SWAPFILE; |
| up(&inode->i_sem); |
| } |
| filp_close(swap_file, NULL); |
| err = 0; |
| |
| out_dput: |
| filp_close(victim, NULL); |
| out: |
| return err; |
| } |
| |
| #ifdef CONFIG_PROC_FS |
| /* iterator */ |
| static void *swap_start(struct seq_file *swap, loff_t *pos) |
| { |
| struct swap_info_struct *ptr = swap_info; |
| int i; |
| loff_t l = *pos; |
| |
| down(&swapon_sem); |
| |
| for (i = 0; i < nr_swapfiles; i++, ptr++) { |
| if (!(ptr->flags & SWP_USED) || !ptr->swap_map) |
| continue; |
| if (!l--) |
| return ptr; |
| } |
| |
| return NULL; |
| } |
| |
| static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) |
| { |
| struct swap_info_struct *ptr = v; |
| struct swap_info_struct *endptr = swap_info + nr_swapfiles; |
| |
| for (++ptr; ptr < endptr; ptr++) { |
| if (!(ptr->flags & SWP_USED) || !ptr->swap_map) |
| continue; |
| ++*pos; |
| return ptr; |
| } |
| |
| return NULL; |
| } |
| |
| static void swap_stop(struct seq_file *swap, void *v) |
| { |
| up(&swapon_sem); |
| } |
| |
| static int swap_show(struct seq_file *swap, void *v) |
| { |
| struct swap_info_struct *ptr = v; |
| struct file *file; |
| int len; |
| |
| if (v == swap_info) |
| seq_puts(swap, "Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n"); |
| |
| file = ptr->swap_file; |
| len = seq_path(swap, file->f_vfsmnt, file->f_dentry, " \t\n\\"); |
| seq_printf(swap, "%*s%s\t%d\t%ld\t%d\n", |
| len < 40 ? 40 - len : 1, " ", |
| S_ISBLK(file->f_dentry->d_inode->i_mode) ? |
| "partition" : "file\t", |
| ptr->pages << (PAGE_SHIFT - 10), |
| ptr->inuse_pages << (PAGE_SHIFT - 10), |
| ptr->prio); |
| return 0; |
| } |
| |
| static struct seq_operations swaps_op = { |
| .start = swap_start, |
| .next = swap_next, |
| .stop = swap_stop, |
| .show = swap_show |
| }; |
| |
| static int swaps_open(struct inode *inode, struct file *file) |
| { |
| return seq_open(file, &swaps_op); |
| } |
| |
| static struct file_operations proc_swaps_operations = { |
| .open = swaps_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| }; |
| |
| static int __init procswaps_init(void) |
| { |
| struct proc_dir_entry *entry; |
| |
| entry = create_proc_entry("swaps", 0, NULL); |
| if (entry) |
| entry->proc_fops = &proc_swaps_operations; |
| return 0; |
| } |
| __initcall(procswaps_init); |
| #endif /* CONFIG_PROC_FS */ |
| |
| /* |
| * Written 01/25/92 by Simmule Turner, heavily changed by Linus. |
| * |
| * The swapon system call |
| */ |
| asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) |
| { |
| struct swap_info_struct * p; |
| char *name = NULL; |
| struct block_device *bdev = NULL; |
| struct file *swap_file = NULL; |
| struct address_space *mapping; |
| unsigned int type; |
| int i, prev; |
| int error; |
| static int least_priority; |
| union swap_header *swap_header = NULL; |
| int swap_header_version; |
| int nr_good_pages = 0; |
| unsigned long maxpages = 1; |
| int swapfilesize; |
| unsigned short *swap_map; |
| struct page *page = NULL; |
| struct inode *inode = NULL; |
| int did_down = 0; |
| |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| swap_list_lock(); |
| p = swap_info; |
| for (type = 0 ; type < nr_swapfiles ; type++,p++) |
| if (!(p->flags & SWP_USED)) |
| break; |
| error = -EPERM; |
| /* |
| * Test if adding another swap device is possible. There are |
| * two limiting factors: 1) the number of bits for the swap |
| * type swp_entry_t definition and 2) the number of bits for |
| * the swap type in the swap ptes as defined by the different |
| * architectures. To honor both limitations a swap entry |
| * with swap offset 0 and swap type ~0UL is created, encoded |
| * to a swap pte, decoded to a swp_entry_t again and finally |
| * the swap type part is extracted. This will mask all bits |
| * from the initial ~0UL that can't be encoded in either the |
| * swp_entry_t or the architecture definition of a swap pte. |
| */ |
| if (type > swp_type(pte_to_swp_entry(swp_entry_to_pte(swp_entry(~0UL,0))))) { |
| swap_list_unlock(); |
| goto out; |
| } |
| if (type >= nr_swapfiles) |
| nr_swapfiles = type+1; |
| INIT_LIST_HEAD(&p->extent_list); |
| p->flags = SWP_USED; |
| p->nr_extents = 0; |
| p->swap_file = NULL; |
| p->old_block_size = 0; |
| p->swap_map = NULL; |
| p->lowest_bit = 0; |
| p->highest_bit = 0; |
| p->cluster_nr = 0; |
| p->inuse_pages = 0; |
| spin_lock_init(&p->sdev_lock); |
| p->next = -1; |
| if (swap_flags & SWAP_FLAG_PREFER) { |
| p->prio = |
| (swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT; |
| } else { |
| p->prio = --least_priority; |
| } |
| swap_list_unlock(); |
| name = getname(specialfile); |
| error = PTR_ERR(name); |
| if (IS_ERR(name)) { |
| name = NULL; |
| goto bad_swap_2; |
| } |
| swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); |
| error = PTR_ERR(swap_file); |
| if (IS_ERR(swap_file)) { |
| swap_file = NULL; |
| goto bad_swap_2; |
| } |
| |
| p->swap_file = swap_file; |
| mapping = swap_file->f_mapping; |
| inode = mapping->host; |
| |
| error = -EBUSY; |
| for (i = 0; i < nr_swapfiles; i++) { |
| struct swap_info_struct *q = &swap_info[i]; |
| |
| if (i == type || !q->swap_file) |
| continue; |
| if (mapping == q->swap_file->f_mapping) |
| goto bad_swap; |
| } |
| |
| error = -EINVAL; |
| if (S_ISBLK(inode->i_mode)) { |
| bdev = I_BDEV(inode); |
| error = bd_claim(bdev, sys_swapon); |
| if (error < 0) { |
| bdev = NULL; |
| goto bad_swap; |
| } |
| p->old_block_size = block_size(bdev); |
| error = set_blocksize(bdev, PAGE_SIZE); |
| if (error < 0) |
| goto bad_swap; |
| p->bdev = bdev; |
| } else if (S_ISREG(inode->i_mode)) { |
| p->bdev = inode->i_sb->s_bdev; |
| down(&inode->i_sem); |
| did_down = 1; |
| if (IS_SWAPFILE(inode)) { |
| error = -EBUSY; |
| goto bad_swap; |
| } |
| } else { |
| goto bad_swap; |
| } |
| |
| swapfilesize = i_size_read(inode) >> PAGE_SHIFT; |
| |
| /* |
| * Read the swap header. |
| */ |
| if (!mapping->a_ops->readpage) { |
| error = -EINVAL; |
| goto bad_swap; |
| } |
| page = read_cache_page(mapping, 0, |
| (filler_t *)mapping->a_ops->readpage, swap_file); |
| if (IS_ERR(page)) { |
| error = PTR_ERR(page); |
| goto bad_swap; |
| } |
| wait_on_page_locked(page); |
| if (!PageUptodate(page)) |
| goto bad_swap; |
| kmap(page); |
| swap_header = page_address(page); |
| |
| if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10)) |
| swap_header_version = 1; |
| else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10)) |
| swap_header_version = 2; |
| else { |
| printk("Unable to find swap-space signature\n"); |
| error = -EINVAL; |
| goto bad_swap; |
| } |
| |
| switch (swap_header_version) { |
| case 1: |
| printk(KERN_ERR "version 0 swap is no longer supported. " |
| "Use mkswap -v1 %s\n", name); |
| error = -EINVAL; |
| goto bad_swap; |
| case 2: |
| /* Check the swap header's sub-version and the size of |
| the swap file and bad block lists */ |
| if (swap_header->info.version != 1) { |
| printk(KERN_WARNING |
| "Unable to handle swap header version %d\n", |
| swap_header->info.version); |
| error = -EINVAL; |
| goto bad_swap; |
| } |
| |
| p->lowest_bit = 1; |
| /* |
| * 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 a 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; |
| if (maxpages > swap_header->info.last_page) |
| maxpages = swap_header->info.last_page; |
| p->highest_bit = maxpages - 1; |
| |
| error = -EINVAL; |
| if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) |
| goto bad_swap; |
| |
| /* OK, set up the swap map and apply the bad block list */ |
| if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { |
| error = -ENOMEM; |
| goto bad_swap; |
| } |
| |
| error = 0; |
| memset(p->swap_map, 0, maxpages * sizeof(short)); |
| for (i=0; i<swap_header->info.nr_badpages; i++) { |
| int page = swap_header->info.badpages[i]; |
| if (page <= 0 || page >= swap_header->info.last_page) |
| error = -EINVAL; |
| else |
| p->swap_map[page] = SWAP_MAP_BAD; |
| } |
| nr_good_pages = swap_header->info.last_page - |
| swap_header->info.nr_badpages - |
| 1 /* header page */; |
| if (error) |
| goto bad_swap; |
| } |
| |
| if (swapfilesize && maxpages > swapfilesize) { |
| printk(KERN_WARNING |
| "Swap area shorter than signature indicates\n"); |
| error = -EINVAL; |
| goto bad_swap; |
| } |
| if (!nr_good_pages) { |
| printk(KERN_WARNING "Empty swap-file\n"); |
| error = -EINVAL; |
| goto bad_swap; |
| } |
| p->swap_map[0] = SWAP_MAP_BAD; |
| p->max = maxpages; |
| p->pages = nr_good_pages; |
| |
| error = setup_swap_extents(p); |
| if (error) |
| goto bad_swap; |
| |
| down(&swapon_sem); |
| swap_list_lock(); |
| swap_device_lock(p); |
| p->flags = SWP_ACTIVE; |
| nr_swap_pages += nr_good_pages; |
| total_swap_pages += nr_good_pages; |
| printk(KERN_INFO "Adding %dk swap on %s. Priority:%d extents:%d\n", |
| nr_good_pages<<(PAGE_SHIFT-10), name, |
| p->prio, p->nr_extents); |
| |
| /* insert swap space into swap_list: */ |
| prev = -1; |
| for (i = swap_list.head; i >= 0; i = swap_info[i].next) { |
| if (p->prio >= swap_info[i].prio) { |
| break; |
| } |
| prev = i; |
| } |
| p->next = i; |
| if (prev < 0) { |
| swap_list.head = swap_list.next = p - swap_info; |
| } else { |
| swap_info[prev].next = p - swap_info; |
| } |
| swap_device_unlock(p); |
| swap_list_unlock(); |
| up(&swapon_sem); |
| error = 0; |
| goto out; |
| bad_swap: |
| if (bdev) { |
| set_blocksize(bdev, p->old_block_size); |
| bd_release(bdev); |
| } |
| bad_swap_2: |
| swap_list_lock(); |
| swap_map = p->swap_map; |
| p->swap_file = NULL; |
| p->swap_map = NULL; |
| p->flags = 0; |
| if (!(swap_flags & SWAP_FLAG_PREFER)) |
| ++least_priority; |
| swap_list_unlock(); |
| destroy_swap_extents(p); |
| vfree(swap_map); |
| if (swap_file) |
| filp_close(swap_file, NULL); |
| out: |
| if (page && !IS_ERR(page)) { |
| kunmap(page); |
| page_cache_release(page); |
| } |
| if (name) |
| putname(name); |
| if (did_down) { |
| if (!error) |
| inode->i_flags |= S_SWAPFILE; |
| up(&inode->i_sem); |
| } |
| return error; |
| } |
| |
| void si_swapinfo(struct sysinfo *val) |
| { |
| unsigned int i; |
| unsigned long nr_to_be_unused = 0; |
| |
| swap_list_lock(); |
| for (i = 0; i < nr_swapfiles; i++) { |
| if (!(swap_info[i].flags & SWP_USED) || |
| (swap_info[i].flags & SWP_WRITEOK)) |
| continue; |
| nr_to_be_unused += swap_info[i].inuse_pages; |
| } |
| val->freeswap = nr_swap_pages + nr_to_be_unused; |
| val->totalswap = total_swap_pages + nr_to_be_unused; |
| swap_list_unlock(); |
| } |
| |
| /* |
| * Verify that a swap entry is valid and increment its swap map count. |
| * |
| * Note: if swap_map[] reaches SWAP_MAP_MAX the entries are treated as |
| * "permanent", but will be reclaimed by the next swapoff. |
| */ |
| int swap_duplicate(swp_entry_t entry) |
| { |
| struct swap_info_struct * p; |
| unsigned long offset, type; |
| int result = 0; |
| |
| type = swp_type(entry); |
| if (type >= nr_swapfiles) |
| goto bad_file; |
| p = type + swap_info; |
| offset = swp_offset(entry); |
| |
| swap_device_lock(p); |
| if (offset < p->max && p->swap_map[offset]) { |
| if (p->swap_map[offset] < SWAP_MAP_MAX - 1) { |
| p->swap_map[offset]++; |
| result = 1; |
| } else if (p->swap_map[offset] <= SWAP_MAP_MAX) { |
| if (swap_overflow++ < 5) |
| printk(KERN_WARNING "swap_dup: swap entry overflow\n"); |
| p->swap_map[offset] = SWAP_MAP_MAX; |
| result = 1; |
| } |
| } |
| swap_device_unlock(p); |
| out: |
| return result; |
| |
| bad_file: |
| printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val); |
| goto out; |
| } |
| |
| struct swap_info_struct * |
| get_swap_info_struct(unsigned type) |
| { |
| return &swap_info[type]; |
| } |
| |
| /* |
| * swap_device_lock prevents swap_map being freed. Don't grab an extra |
| * reference on the swaphandle, it doesn't matter if it becomes unused. |
| */ |
| int valid_swaphandles(swp_entry_t entry, unsigned long *offset) |
| { |
| int ret = 0, i = 1 << page_cluster; |
| unsigned long toff; |
| struct swap_info_struct *swapdev = swp_type(entry) + swap_info; |
| |
| if (!page_cluster) /* no readahead */ |
| return 0; |
| toff = (swp_offset(entry) >> page_cluster) << page_cluster; |
| if (!toff) /* first page is swap header */ |
| toff++, i--; |
| *offset = toff; |
| |
| swap_device_lock(swapdev); |
| do { |
| /* Don't read-ahead past the end of the swap area */ |
| if (toff >= swapdev->max) |
| break; |
| /* Don't read in free or bad pages */ |
| if (!swapdev->swap_map[toff]) |
| break; |
| if (swapdev->swap_map[toff] == SWAP_MAP_BAD) |
| break; |
| toff++; |
| ret++; |
| } while (--i); |
| swap_device_unlock(swapdev); |
| return ret; |
| } |