diff options
Diffstat (limited to 'old/xenolinux-2.4.16-sparse/mm/swapfile.c')
| -rw-r--r-- | old/xenolinux-2.4.16-sparse/mm/swapfile.c | 1291 |
1 files changed, 0 insertions, 1291 deletions
diff --git a/old/xenolinux-2.4.16-sparse/mm/swapfile.c b/old/xenolinux-2.4.16-sparse/mm/swapfile.c deleted file mode 100644 index 48846184d4..0000000000 --- a/old/xenolinux-2.4.16-sparse/mm/swapfile.c +++ /dev/null @@ -1,1291 +0,0 @@ -/* - * linux/mm/swapfile.c - * - * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds - * Swap reorganised 29.12.95, Stephen Tweedie - */ - -#include <linux/slab.h> -#include <linux/smp_lock.h> -#include <linux/kernel_stat.h> -#include <linux/swap.h> -#include <linux/swapctl.h> -#include <linux/blkdev.h> /* for blk_size */ -#include <linux/vmalloc.h> -#include <linux/pagemap.h> -#include <linux/shm.h> -#include <linux/compiler.h> - -#include <asm/pgtable.h> - -spinlock_t swaplock = SPIN_LOCK_UNLOCKED; -unsigned int nr_swapfiles; -int total_swap_pages; -static int swap_overflow; - -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]; - -#define SWAPFILE_CLUSTER 256 - -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) - { - int 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; - 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_WRITEOK) == SWP_WRITEOK) { - 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++; - } - } - 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); - } -} - -/* - * Check if we're the only user of a swap page, - * when the page is locked. - */ -static int exclusive_swap_page(struct page *page) -{ - int retval = 0; - struct swap_info_struct * p; - swp_entry_t entry; - - entry.val = page->index; - p = swap_info_get(entry); - if (p) { - /* Is the only swap cache user the cache itself? */ - if (p->swap_map[SWP_OFFSET(entry)] == 1) { - /* Recheck the page count with the pagecache lock held.. */ - spin_lock(&pagecache_lock); - if (page_count(page) - !!page->buffers == 2) - retval = 1; - spin_unlock(&pagecache_lock); - } - swap_info_put(p); - } - return retval; -} - -/* - * We can use this swap cache entry directly - * if there are no other references to it. - * - * Here "exclusive_swap_page()" does the real - * work, but we opportunistically check whether - * we need to get all the locks first.. - */ -int can_share_swap_page(struct page *page) -{ - int retval = 0; - - if (!PageLocked(page)) - BUG(); - switch (page_count(page)) { - case 3: - if (!page->buffers) - break; - /* Fallthrough */ - case 2: - if (!PageSwapCache(page)) - break; - retval = exclusive_swap_page(page); - break; - case 1: - if (PageReserved(page)) - break; - retval = 1; - } - return retval; -} - -/* - * 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; - - if (!PageLocked(page)) - BUG(); - if (!PageSwapCache(page)) - return 0; - if (page_count(page) - !!page->buffers != 2) /* 2: us + cache */ - return 0; - - entry.val = page->index; - 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 pagecache lock held.. */ - spin_lock(&pagecache_lock); - if (page_count(page) - !!page->buffers == 2) { - __delete_from_swap_cache(page); - SetPageDirty(page); - retval = 1; - } - spin_unlock(&pagecache_lock); - } - swap_info_put(p); - - if (retval) { - block_flushpage(page, 0); - 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) { - page_cache_get(page); - /* Only cache user (+us), or swap space full? Free it! */ - if (page_count(page) == 2 || vm_swap_full()) { - delete_from_swap_cache(page); - SetPageDirty(page); - } - UnlockPage(page); - page_cache_release(page); - } -} - -/* - * The swap entry has been read in advance, and we return 1 to indicate - * that the page has been used or is no longer needed. - * - * 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. - */ -/* mmlist_lock and vma->vm_mm->page_table_lock are held */ -static inline void unuse_pte(struct vm_area_struct * vma, unsigned long address, - pte_t *dir, swp_entry_t entry, struct page* page) -{ - pte_t pte = *dir; - - if (likely(pte_to_swp_entry(pte).val != entry.val)) - return; - if (unlikely(pte_none(pte) || pte_present(pte))) - return; - get_page(page); - set_pte(dir, pte_mkold(mk_pte(page, vma->vm_page_prot))); - swap_free(entry); - ++vma->vm_mm->rss; -} - -/* mmlist_lock and vma->vm_mm->page_table_lock are held */ -static inline void unuse_pmd(struct vm_area_struct * vma, pmd_t *dir, - unsigned long address, unsigned long size, unsigned long offset, - swp_entry_t entry, struct page* page) -{ - pte_t * pte; - unsigned long end; - - if (pmd_none(*dir)) - return; - if (pmd_bad(*dir)) { - pmd_ERROR(*dir); - pmd_clear(dir); - return; - } - pte = pte_offset(dir, address); - offset += address & PMD_MASK; - address &= ~PMD_MASK; - end = address + size; - if (end > PMD_SIZE) - end = PMD_SIZE; - do { - unuse_pte(vma, offset+address-vma->vm_start, pte, entry, page); - address += PAGE_SIZE; - pte++; - } while (address && (address < end)); -} - -/* mmlist_lock and vma->vm_mm->page_table_lock are held */ -static inline void unuse_pgd(struct vm_area_struct * vma, pgd_t *dir, - unsigned long address, unsigned long size, - swp_entry_t entry, struct page* page) -{ - pmd_t * pmd; - unsigned long offset, end; - - if (pgd_none(*dir)) - return; - if (pgd_bad(*dir)) { - pgd_ERROR(*dir); - pgd_clear(dir); - return; - } - pmd = pmd_offset(dir, address); - offset = address & PGDIR_MASK; - address &= ~PGDIR_MASK; - end = address + size; - if (end > PGDIR_SIZE) - end = PGDIR_SIZE; - if (address >= end) - BUG(); - do { - unuse_pmd(vma, pmd, address, end - address, offset, entry, - page); - address = (address + PMD_SIZE) & PMD_MASK; - pmd++; - } while (address && (address < end)); -} - -/* mmlist_lock and vma->vm_mm->page_table_lock are held */ -static void unuse_vma(struct vm_area_struct * vma, pgd_t *pgdir, - swp_entry_t entry, struct page* page) -{ - unsigned long start = vma->vm_start, end = vma->vm_end; - - if (start >= end) - BUG(); - do { - unuse_pgd(vma, pgdir, start, end - start, entry, page); - start = (start + PGDIR_SIZE) & PGDIR_MASK; - pgdir++; - } while (start && (start < end)); -} - -static void unuse_process(struct mm_struct * mm, - swp_entry_t entry, struct page* page) -{ - struct vm_area_struct* vma; - - /* - * Go through process' page directory. - */ - spin_lock(&mm->page_table_lock); - for (vma = mm->mmap; vma; vma = vma->vm_next) { - pgd_t * pgd = pgd_offset(mm, vma->vm_start); - unuse_vma(vma, pgd, entry, page); - } - XENO_flush_page_update_queue(); - spin_unlock(&mm->page_table_lock); - return; -} - -/* - * 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; - - /* - * 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 (now preserved by swap_out()), - * which clusters forked address spaces together, most recent - * child immediately after parent. If we race with dup_mmap(), - * we very much want to resolve parent before child, otherwise - * we may miss some entries: using last mm would invert that. - */ - 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: - * mmput() removes mm from mmlist before exit_mmap() and its - * zap_page_range(). That's not too bad, those entries are - * on their way out, and handled faster there than here. - * do_munmap() behaves similarly, taking the range out of mm's - * vma list before zap_page_range(). But unfortunately, when - * unmapping a part of a vma, it takes the whole out first, - * then reinserts what's left after (might even reschedule if - * open() method called) - so swap entries may be invisible - * to swapoff for a while, then reappear - but that is rare. - */ - while ((i = find_next_to_unuse(si, i))) { - /* - * 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); - 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" 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(page); - lock_page(page); - - /* - * Remove all references to entry, without blocking. - * Whenever we reach init_mm, there's no address space - * to search, but use it as a reminder to search shmem. - */ - swcount = *swap_map; - if (swcount > 1) { - flush_page_to_ram(page); - if (start_mm == &init_mm) - shmem_unuse(entry, page); - else - unuse_process(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 *mm; - - spin_lock(&mmlist_lock); - while (*swap_map > 1 && - (p = p->next) != &start_mm->mmlist) { - mm = list_entry(p, struct mm_struct, mmlist); - swcount = *swap_map; - if (mm == &init_mm) { - set_start_mm = 1; - shmem_unuse(entry, page); - } else - unuse_process(mm, entry, page); - if (set_start_mm && *swap_map < swcount) { - new_start_mm = mm; - set_start_mm = 0; - } - } - atomic_inc(&new_start_mm->mm_users); - spin_unlock(&mmlist_lock); - mmput(start_mm); - start_mm = new_start_mm; - } - - /* - * 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_list_lock(); - swap_device_lock(si); - nr_swap_pages++; - *swap_map = 1; - swap_device_unlock(si); - swap_list_unlock(); - reset_overflow = 1; - } - - /* - * If a reference remains (rare), we would like to leave - * the page in the swap cache; but try_to_swap_out 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 its from swap cache. - */ - swcount = *swap_map; - if ((swcount > 0) != PageSwapCache(page)) - BUG(); - if ((swcount > 1) && PageDirty(page)) { - rw_swap_page(WRITE, page); - lock_page(page); - } - if (PageSwapCache(page)) - 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 try_to_swap_out will preserve it. - */ - SetPageDirty(page); - UnlockPage(page); - page_cache_release(page); - - /* - * Make sure that we aren't completely killing - * interactive performance. Interruptible check on - * signal_pending() would be nice, but changes the spec? - */ - if (current->need_resched) - schedule(); - } - - mmput(start_mm); - if (reset_overflow) { - printk(KERN_WARNING "swapoff: cleared swap entry overflow\n"); - swap_overflow = 0; - } - return retval; -} - -asmlinkage long sys_swapoff(const char * specialfile) -{ - struct swap_info_struct * p = NULL; - unsigned short *swap_map; - struct nameidata nd; - int i, type, prev; - int err; - - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - - err = user_path_walk(specialfile, &nd); - if (err) - goto out; - - lock_kernel(); - 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_WRITEOK) == SWP_WRITEOK) { - if (p->swap_file == nd.dentry) - break; - } - prev = type; - } - err = -EINVAL; - if (type < 0) { - 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_USED; - swap_list_unlock(); - unlock_kernel(); - err = try_to_unuse(type); - lock_kernel(); - 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; - } - if (p->swap_device) - blkdev_put(p->swap_file->d_inode->i_bdev, BDEV_SWAP); - path_release(&nd); - - swap_list_lock(); - swap_device_lock(p); - nd.mnt = p->swap_vfsmnt; - nd.dentry = p->swap_file; - p->swap_vfsmnt = NULL; - p->swap_file = NULL; - p->swap_device = 0; - p->max = 0; - swap_map = p->swap_map; - p->swap_map = NULL; - p->flags = 0; - swap_device_unlock(p); - swap_list_unlock(); - vfree(swap_map); - err = 0; - -out_dput: - unlock_kernel(); - path_release(&nd); -out: - return err; -} - -int get_swaparea_info(char *buf) -{ - char * page = (char *) __get_free_page(GFP_KERNEL); - struct swap_info_struct *ptr = swap_info; - int i, j, len = 0, usedswap; - - if (!page) - return -ENOMEM; - - len += sprintf(buf, "Filename\t\t\tType\t\tSize\tUsed\tPriority\n"); - for (i = 0 ; i < nr_swapfiles ; i++, ptr++) { - if ((ptr->flags & SWP_USED) && ptr->swap_map) { - char * path = d_path(ptr->swap_file, ptr->swap_vfsmnt, - page, PAGE_SIZE); - - len += sprintf(buf + len, "%-31s ", path); - - if (!ptr->swap_device) - len += sprintf(buf + len, "file\t\t"); - else - len += sprintf(buf + len, "partition\t"); - - usedswap = 0; - for (j = 0; j < ptr->max; ++j) - switch (ptr->swap_map[j]) { - case SWAP_MAP_BAD: - case 0: - continue; - default: - usedswap++; - } - len += sprintf(buf + len, "%d\t%d\t%d\n", ptr->pages << (PAGE_SHIFT - 10), - usedswap << (PAGE_SHIFT - 10), ptr->prio); - } - } - free_page((unsigned long) page); - return len; -} - -int is_swap_partition(kdev_t dev) { - struct swap_info_struct *ptr = swap_info; - int i; - - for (i = 0 ; i < nr_swapfiles ; i++, ptr++) { - if (ptr->flags & SWP_USED) - if (ptr->swap_device == dev) - return 1; - } - return 0; -} - -/* - * Written 01/25/92 by Simmule Turner, heavily changed by Linus. - * - * The swapon system call - */ -asmlinkage long sys_swapon(const char * specialfile, int swap_flags) -{ - struct swap_info_struct * p; - struct nameidata nd; - struct inode * swap_inode; - unsigned int type; - int i, j, prev; - int error; - static int least_priority = 0; - union swap_header *swap_header = 0; - int swap_header_version; - int nr_good_pages = 0; - unsigned long maxpages = 1; - int swapfilesize; - struct block_device *bdev = NULL; - unsigned short *swap_map; - - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - lock_kernel(); - swap_list_lock(); - p = swap_info; - for (type = 0 ; type < nr_swapfiles ; type++,p++) - if (!(p->flags & SWP_USED)) - break; - error = -EPERM; - if (type >= MAX_SWAPFILES) { - swap_list_unlock(); - goto out; - } - if (type >= nr_swapfiles) - nr_swapfiles = type+1; - p->flags = SWP_USED; - p->swap_file = NULL; - p->swap_vfsmnt = NULL; - p->swap_device = 0; - p->swap_map = NULL; - p->lowest_bit = 0; - p->highest_bit = 0; - p->cluster_nr = 0; - p->sdev_lock = SPIN_LOCK_UNLOCKED; - 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(); - error = user_path_walk(specialfile, &nd); - if (error) - goto bad_swap_2; - - p->swap_file = nd.dentry; - p->swap_vfsmnt = nd.mnt; - swap_inode = nd.dentry->d_inode; - error = -EINVAL; - - if (S_ISBLK(swap_inode->i_mode)) { - kdev_t dev = swap_inode->i_rdev; - struct block_device_operations *bdops; - - p->swap_device = dev; - set_blocksize(dev, PAGE_SIZE); - - bd_acquire(swap_inode); - bdev = swap_inode->i_bdev; - bdops = devfs_get_ops(devfs_get_handle_from_inode(swap_inode)); - if (bdops) bdev->bd_op = bdops; - - error = blkdev_get(bdev, FMODE_READ|FMODE_WRITE, 0, BDEV_SWAP); - if (error) - goto bad_swap_2; - set_blocksize(dev, PAGE_SIZE); - error = -ENODEV; - if (!dev || (blk_size[MAJOR(dev)] && - !blk_size[MAJOR(dev)][MINOR(dev)])) - goto bad_swap; - swapfilesize = 0; - if (blk_size[MAJOR(dev)]) - swapfilesize = blk_size[MAJOR(dev)][MINOR(dev)] - >> (PAGE_SHIFT - 10); - } else if (S_ISREG(swap_inode->i_mode)) - swapfilesize = swap_inode->i_size >> PAGE_SHIFT; - else - goto bad_swap; - - 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 (swap_inode->i_mapping == q->swap_file->d_inode->i_mapping) - goto bad_swap; - } - - swap_header = (void *) __get_free_page(GFP_USER); - if (!swap_header) { - printk("Unable to start swapping: out of memory :-)\n"); - error = -ENOMEM; - goto bad_swap; - } - - lock_page(virt_to_page(swap_header)); - rw_swap_page_nolock(READ, SWP_ENTRY(type,0), (char *) swap_header); - - 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: - memset(((char *) swap_header)+PAGE_SIZE-10,0,10); - j = 0; - p->lowest_bit = 0; - p->highest_bit = 0; - for (i = 1 ; i < 8*PAGE_SIZE ; i++) { - if (test_bit(i,(char *) swap_header)) { - if (!p->lowest_bit) - p->lowest_bit = i; - p->highest_bit = i; - maxpages = i+1; - j++; - } - } - nr_good_pages = j; - p->swap_map = vmalloc(maxpages * sizeof(short)); - if (!p->swap_map) { - error = -ENOMEM; - goto bad_swap; - } - for (i = 1 ; i < maxpages ; i++) { - if (test_bit(i,(char *) swap_header)) - p->swap_map[i] = 0; - else - p->swap_map[i] = SWAP_MAP_BAD; - } - break; - - 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; - maxpages = SWP_OFFSET(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; - swap_list_lock(); - swap_device_lock(p); - p->max = maxpages; - p->flags = SWP_WRITEOK; - p->pages = nr_good_pages; - nr_swap_pages += nr_good_pages; - total_swap_pages += nr_good_pages; - printk(KERN_INFO "Adding Swap: %dk swap-space (priority %d)\n", - nr_good_pages<<(PAGE_SHIFT-10), p->prio); - - /* 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(); - error = 0; - goto out; -bad_swap: - if (bdev) - blkdev_put(bdev, BDEV_SWAP); -bad_swap_2: - swap_list_lock(); - swap_map = p->swap_map; - nd.mnt = p->swap_vfsmnt; - nd.dentry = p->swap_file; - p->swap_device = 0; - p->swap_file = NULL; - p->swap_vfsmnt = NULL; - p->swap_map = NULL; - p->flags = 0; - if (!(swap_flags & SWAP_FLAG_PREFER)) - ++least_priority; - swap_list_unlock(); - if (swap_map) - vfree(swap_map); - path_release(&nd); -out: - if (swap_header) - free_page((long) swap_header); - unlock_kernel(); - 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++) { - unsigned int j; - if (swap_info[i].flags != SWP_USED) - continue; - for (j = 0; j < swap_info[i].max; ++j) { - switch (swap_info[i].swap_map[j]) { - case 0: - case SWAP_MAP_BAD: - continue; - default: - nr_to_be_unused++; - } - } - } - 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; -} - -/* - * Page lock needs to be held in all cases to prevent races with - * swap file deletion. - */ -int swap_count(struct page *page) -{ - struct swap_info_struct * p; - unsigned long offset, type; - swp_entry_t entry; - int retval = 0; - - entry.val = page->index; - if (!entry.val) - goto bad_entry; - type = SWP_TYPE(entry); - if (type >= nr_swapfiles) - goto bad_file; - p = type + swap_info; - offset = SWP_OFFSET(entry); - if (offset >= p->max) - goto bad_offset; - if (!p->swap_map[offset]) - goto bad_unused; - retval = p->swap_map[offset]; -out: - return retval; - -bad_entry: - printk(KERN_ERR "swap_count: null entry!\n"); - goto out; -bad_file: - printk(KERN_ERR "swap_count: %s%08lx\n", Bad_file, entry.val); - goto out; -bad_offset: - printk(KERN_ERR "swap_count: %s%08lx\n", Bad_offset, entry.val); - goto out; -bad_unused: - printk(KERN_ERR "swap_count: %s%08lx\n", Unused_offset, entry.val); - goto out; -} - -/* - * Prior swap_duplicate protects against swap device deletion. - */ -void get_swaphandle_info(swp_entry_t entry, unsigned long *offset, - kdev_t *dev, struct inode **swapf) -{ - unsigned long type; - struct swap_info_struct *p; - - type = SWP_TYPE(entry); - if (type >= nr_swapfiles) { - printk(KERN_ERR "rw_swap_page: %s%08lx\n", Bad_file, entry.val); - return; - } - - p = &swap_info[type]; - *offset = SWP_OFFSET(entry); - if (*offset >= p->max && *offset != 0) { - printk(KERN_ERR "rw_swap_page: %s%08lx\n", Bad_offset, entry.val); - return; - } - if (p->swap_map && !p->swap_map[*offset]) { - printk(KERN_ERR "rw_swap_page: %s%08lx\n", Unused_offset, entry.val); - return; - } - if (!(p->flags & SWP_USED)) { - printk(KERN_ERR "rw_swap_page: %s%08lx\n", Unused_file, entry.val); - return; - } - - if (p->swap_device) { - *dev = p->swap_device; - } else if (p->swap_file) { - *swapf = p->swap_file->d_inode; - } else { - printk(KERN_ERR "rw_swap_page: no swap file or device\n"); - } - return; -} - -/* - * 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; -} |