1 files changed, 58 insertions, 8 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 7c703ff2f36f..0341c5700e34 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -30,6 +30,7 @@
 #include <linux/capability.h>
 #include <linux/syscalls.h>
 #include <linux/memcontrol.h>
+#include <linux/poll.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -58,6 +59,10 @@ static struct swap_info_struct *swap_info[MAX_SWAPFILES];
 
 static DEFINE_MUTEX(swapon_mutex);
 
+static DECLARE_WAIT_QUEUE_HEAD(proc_poll_wait);
+/* Activity counter to indicate that a swapon or swapoff has occurred */
+static atomic_t proc_poll_event = ATOMIC_INIT(0);
+
 static inline unsigned char swap_count(unsigned char ent)
 {
 	return ent & ~SWAP_HAS_CACHE;	/* may include SWAP_HAS_CONT flag */
@@ -139,7 +144,7 @@ static int discard_swap(struct swap_info_struct *si)
 	nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9);
 	if (nr_blocks) {
 		err = blkdev_issue_discard(si->bdev, start_block,
-				nr_blocks, GFP_KERNEL, BLKDEV_IFL_WAIT);
+				nr_blocks, GFP_KERNEL, 0);
 		if (err)
 			return err;
 		cond_resched();
@@ -150,7 +155,7 @@ static int discard_swap(struct swap_info_struct *si)
 		nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9);
 
 		err = blkdev_issue_discard(si->bdev, start_block,
-				nr_blocks, GFP_KERNEL, BLKDEV_IFL_WAIT);
+				nr_blocks, GFP_KERNEL, 0);
 		if (err)
 			break;
 
@@ -189,7 +194,7 @@ static void discard_swap_cluster(struct swap_info_struct *si,
 			start_block <<= PAGE_SHIFT - 9;
 			nr_blocks <<= PAGE_SHIFT - 9;
 			if (blkdev_issue_discard(si->bdev, start_block,
-				    nr_blocks, GFP_NOIO, BLKDEV_IFL_WAIT))
+				    nr_blocks, GFP_NOIO, 0))
 				break;
 		}
 
@@ -959,6 +964,8 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
+		if (unlikely(pmd_trans_huge(*pmd)))
+			continue;
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
 		ret = unuse_pte_range(vma, pmd, addr, next, entry, page);
@@ -1672,7 +1679,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 	if (S_ISBLK(inode->i_mode)) {
 		struct block_device *bdev = I_BDEV(inode);
 		set_blocksize(bdev, p->old_block_size);
-		bd_release(bdev);
+		blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
 	} else {
 		mutex_lock(&inode->i_mutex);
 		inode->i_flags &= ~S_SWAPFILE;
@@ -1680,6 +1687,8 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 	}
 	filp_close(swap_file, NULL);
 	err = 0;
+	atomic_inc(&proc_poll_event);
+	wake_up_interruptible(&proc_poll_wait);
 
 out_dput:
 	filp_close(victim, NULL);
@@ -1688,6 +1697,25 @@ out:
 }
 
 #ifdef CONFIG_PROC_FS
+struct proc_swaps {
+	struct seq_file seq;
+	int event;
+};
+
+static unsigned swaps_poll(struct file *file, poll_table *wait)
+{
+	struct proc_swaps *s = file->private_data;
+
+	poll_wait(file, &proc_poll_wait, wait);
+
+	if (s->event != atomic_read(&proc_poll_event)) {
+		s->event = atomic_read(&proc_poll_event);
+		return POLLIN | POLLRDNORM | POLLERR | POLLPRI;
+	}
+
+	return POLLIN | POLLRDNORM;
+}
+
 /* iterator */
 static void *swap_start(struct seq_file *swap, loff_t *pos)
 {
@@ -1771,7 +1799,24 @@ static const struct seq_operations swaps_op = {
 
 static int swaps_open(struct inode *inode, struct file *file)
 {
-	return seq_open(file, &swaps_op);
+	struct proc_swaps *s;
+	int ret;
+
+	s = kmalloc(sizeof(struct proc_swaps), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	file->private_data = s;
+
+	ret = seq_open(file, &swaps_op);
+	if (ret) {
+		kfree(s);
+		return ret;
+	}
+
+	s->seq.private = s;
+	s->event = atomic_read(&proc_poll_event);
+	return ret;
 }
 
 static const struct file_operations proc_swaps_operations = {
@@ -1779,6 +1824,7 @@ static const struct file_operations proc_swaps_operations = {
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= seq_release,
+	.poll		= swaps_poll,
 };
 
 static int __init procswaps_init(void)
@@ -1894,8 +1940,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 
 	error = -EINVAL;
 	if (S_ISBLK(inode->i_mode)) {
-		bdev = I_BDEV(inode);
-		error = bd_claim(bdev, sys_swapon);
+		bdev = bdgrab(I_BDEV(inode));
+		error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+				   sys_swapon);
 		if (error < 0) {
 			bdev = NULL;
 			error = -EINVAL;
@@ -2084,12 +2131,15 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		swap_info[prev]->next = type;
 	spin_unlock(&swap_lock);
 	mutex_unlock(&swapon_mutex);
+	atomic_inc(&proc_poll_event);
+	wake_up_interruptible(&proc_poll_wait);
+
 	error = 0;
 	goto out;
 bad_swap:
 	if (bdev) {
 		set_blocksize(bdev, p->old_block_size);
-		bd_release(bdev);
+		blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
 	}
 	destroy_swap_extents(p);
 	swap_cgroup_swapoff(type);