In order to realize the interface reuse in the swapoff resource release process, some of the operations are abstracted into separate interfaces. Only code movement, no functional modifications and changes. del_useless_swap_info(): Remove specific swap_info_struct from swap_active_head and update total_swap_pages. release_swap_info_memory(): Clear the corresponding resources of swap_info_struct. Signed-off-by: liubo <liubo254@xxxxxxxxxx> --- v2: Only code movement, no functional modifications and changes. Former: https://lore.kernel.org/linux-mm/20220528084941.28391-1-liubo254@xxxxxxxxxx/ --- mm/swapfile.c | 168 +++++++++++++++++++++++++++----------------------- 1 file changed, 91 insertions(+), 77 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 3fa26f6971e9..2ef5e7b4918e 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2386,18 +2386,103 @@ bool has_usable_swap(void) return ret; } -SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) +static void release_swap_info_memory(struct swap_info_struct *p) { - struct swap_info_struct *p = NULL; unsigned char *swap_map; struct swap_cluster_info *cluster_info; unsigned long *frontswap_map; - struct file *swap_file, *victim; + struct file *swap_file; struct address_space *mapping; struct inode *inode; + unsigned int old_block_size; + + mutex_lock(&swapon_mutex); + spin_lock(&swap_lock); + spin_lock(&p->lock); + drain_mmlist(); + + /* wait for anyone still in scan_swap_map */ + p->highest_bit = 0; /* cuts scans short */ + while (p->flags >= SWP_SCANNING) { + spin_unlock(&p->lock); + spin_unlock(&swap_lock); + schedule_timeout_uninterruptible(1); + spin_lock(&swap_lock); + spin_lock(&p->lock); + } + + swap_file = p->swap_file; + mapping = p->swap_file->f_mapping; + old_block_size = p->old_block_size; + p->swap_file = NULL; + p->max = 0; + swap_map = p->swap_map; + p->swap_map = NULL; + cluster_info = p->cluster_info; + p->cluster_info = NULL; + frontswap_map = frontswap_map_get(p); + spin_unlock(&p->lock); + spin_unlock(&swap_lock); + arch_swap_invalidate_area(p->type); + frontswap_invalidate_area(p->type); + frontswap_map_set(p, NULL); + mutex_unlock(&swapon_mutex); + free_percpu(p->percpu_cluster); + p->percpu_cluster = NULL; + free_percpu(p->cluster_next_cpu); + p->cluster_next_cpu = NULL; + vfree(swap_map); + kvfree(cluster_info); + kvfree(frontswap_map); + /* Destroy swap account information */ + swap_cgroup_swapoff(p->type); + exit_swap_address_space(p->type); + + inode = mapping->host; + if (S_ISBLK(inode->i_mode)) { + struct block_device *bdev = I_BDEV(inode); + + set_blocksize(bdev, old_block_size); + blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); + } + + inode_lock(inode); + inode->i_flags &= ~S_SWAPFILE; + inode_unlock(inode); + filp_close(swap_file, NULL); +} + +static void del_useless_swap_info(struct swap_info_struct *p) +{ + del_from_avail_list(p); + spin_lock(&p->lock); + if (p->prio < 0) { + struct swap_info_struct *si = p; + int nid; + + plist_for_each_entry_continue(si, &swap_active_head, list) { + si->prio++; + si->list.prio--; + for_each_node(nid) { + if (si->avail_lists[nid].prio != 1) + si->avail_lists[nid].prio--; + } + } + least_priority++; + } + plist_del(&p->list, &swap_active_head); + atomic_long_sub(p->pages, &nr_swap_pages); + p->flags &= ~SWP_WRITEOK; + spin_unlock(&p->lock); +} + +SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) +{ + struct swap_info_struct *p = NULL; + struct file *victim; + struct address_space *mapping; struct filename *pathname; int err, found = 0; - unsigned int old_block_size; unsigned int inuse_pages; if (!capable(CAP_SYS_ADMIN)) @@ -2440,26 +2525,8 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) spin_unlock(&swap_lock); goto out_dput; } - del_from_avail_list(p); - spin_lock(&p->lock); - if (p->prio < 0) { - struct swap_info_struct *si = p; - int nid; - plist_for_each_entry_continue(si, &swap_active_head, list) { - si->prio++; - si->list.prio--; - for_each_node(nid) { - if (si->avail_lists[nid].prio != 1) - si->avail_lists[nid].prio--; - } - } - least_priority++; - } - plist_del(&p->list, &swap_active_head); - atomic_long_sub(p->pages, &nr_swap_pages); - p->flags &= ~SWP_WRITEOK; - spin_unlock(&p->lock); + del_useless_swap_info(p); spin_unlock(&swap_lock); disable_swap_slots_cache_lock(); @@ -2497,60 +2564,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) if (!p->bdev || !bdev_nonrot(p->bdev)) atomic_dec(&nr_rotate_swap); - mutex_lock(&swapon_mutex); - spin_lock(&swap_lock); - spin_lock(&p->lock); - drain_mmlist(); - - /* wait for anyone still in scan_swap_map_slots */ - p->highest_bit = 0; /* cuts scans short */ - while (p->flags >= SWP_SCANNING) { - spin_unlock(&p->lock); - spin_unlock(&swap_lock); - schedule_timeout_uninterruptible(1); - spin_lock(&swap_lock); - spin_lock(&p->lock); - } - - swap_file = p->swap_file; - old_block_size = p->old_block_size; - p->swap_file = NULL; - p->max = 0; - swap_map = p->swap_map; - p->swap_map = NULL; - cluster_info = p->cluster_info; - p->cluster_info = NULL; - frontswap_map = frontswap_map_get(p); - spin_unlock(&p->lock); - spin_unlock(&swap_lock); - arch_swap_invalidate_area(p->type); - frontswap_invalidate_area(p->type); - frontswap_map_set(p, NULL); - mutex_unlock(&swapon_mutex); - free_percpu(p->percpu_cluster); - p->percpu_cluster = NULL; - free_percpu(p->cluster_next_cpu); - p->cluster_next_cpu = NULL; - vfree(swap_map); - kvfree(cluster_info); - kvfree(frontswap_map); - /* Destroy swap account information */ - swap_cgroup_swapoff(p->type); - exit_swap_address_space(p->type); - - inode = mapping->host; - if (S_ISBLK(inode->i_mode)) { - struct block_device *bdev = I_BDEV(inode); - - set_blocksize(bdev, old_block_size); - blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); - } - - inode_lock(inode); - inode->i_flags &= ~S_SWAPFILE; - inode_unlock(inode); - filp_close(swap_file, NULL); - + release_swap_info_memory(p); /* * Clear the SWP_USED flag after all resources are freed so that swapon * can reuse this swap_info in alloc_swap_info() safely. It is ok to -- 2.27.0
