diff options
| -rw-r--r-- | include/linux/swap.h | 2 | ||||
| -rw-r--r-- | mm/swapfile.c | 42 |
2 files changed, 37 insertions, 7 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 93f0eca7f916..db3b5de7c92f 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -107,6 +107,8 @@ enum { SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ SWP_ACTIVE = (SWP_USED | SWP_WRITEOK), + /* add others here before... */ + SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ }; #define SWAP_CLUSTER_MAX 32 diff --git a/mm/swapfile.c b/mm/swapfile.c index c70248aab536..fdee145afc6f 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -98,10 +98,12 @@ static inline unsigned long scan_swap_map(struct swap_info_struct *si) * But we do now try to find an empty cluster. -Andrea */ + si->flags += SWP_SCANNING; if (unlikely(!si->cluster_nr)) { si->cluster_nr = SWAPFILE_CLUSTER - 1; if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) goto lowest; + swap_device_unlock(si); offset = si->lowest_bit; last_in_cluster = offset + SWAPFILE_CLUSTER - 1; @@ -111,10 +113,12 @@ static inline unsigned long scan_swap_map(struct swap_info_struct *si) if (si->swap_map[offset]) last_in_cluster = offset + SWAPFILE_CLUSTER; else if (offset == last_in_cluster) { + swap_device_lock(si); si->cluster_next = offset-SWAPFILE_CLUSTER-1; goto cluster; } } + swap_device_lock(si); goto lowest; } @@ -123,10 +127,12 @@ cluster: offset = si->cluster_next; if (offset > si->highest_bit) lowest: offset = si->lowest_bit; +checks: if (!(si->flags & SWP_WRITEOK)) + goto no_page; if (!si->highest_bit) goto no_page; if (!si->swap_map[offset]) { -got_page: if (offset == si->lowest_bit) + if (offset == si->lowest_bit) si->lowest_bit++; if (offset == si->highest_bit) si->highest_bit--; @@ -137,16 +143,22 @@ got_page: if (offset == si->lowest_bit) } si->swap_map[offset] = 1; si->cluster_next = offset + 1; + si->flags -= SWP_SCANNING; return offset; } + swap_device_unlock(si); while (++offset <= si->highest_bit) { - if (!si->swap_map[offset]) - goto got_page; + if (!si->swap_map[offset]) { + swap_device_lock(si); + goto checks; + } } + swap_device_lock(si); goto lowest; no_page: + si->flags -= SWP_SCANNING; return 0; } @@ -1111,10 +1123,6 @@ asmlinkage long sys_swapoff(const char __user * specialfile) 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(); @@ -1128,10 +1136,28 @@ asmlinkage long sys_swapoff(const char __user * specialfile) swap_info[prev].next = p - swap_info; nr_swap_pages += p->pages; total_swap_pages += p->pages; + swap_device_lock(p); p->flags |= SWP_WRITEOK; + swap_device_unlock(p); swap_list_unlock(); goto out_dput; } + + /* wait for any unplug function to finish */ + down_write(&swap_unplug_sem); + up_write(&swap_unplug_sem); + + /* wait for anyone still in scan_swap_map */ + swap_device_lock(p); + p->highest_bit = 0; /* cuts scans short */ + while (p->flags >= SWP_SCANNING) { + swap_device_unlock(p); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(1); + swap_device_lock(p); + } + swap_device_unlock(p); + destroy_swap_extents(p); down(&swapon_sem); swap_list_lock(); @@ -1431,6 +1457,8 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) } p->lowest_bit = 1; + p->cluster_next = 1; + /* * Find out how many pages are allowed for a single swap * device. There are two limiting factors: 1) the number of |