X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fmm%2Fswapfile.c;h=c1a0f3dea8b5beb197b57619e8153f7d17483f8a;hb=52f993b8e89487ec9ee15a7fb4979e0f09a45b27;hp=a7e72103f23bfbf81aad771343dac77c4f4d1958;hpb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;p=kvmfornfv.git

diff --git a/kernel/mm/swapfile.c b/kernel/mm/swapfile.c
index a7e72103f..c1a0f3dea 100644
--- a/kernel/mm/swapfile.c
+++ b/kernel/mm/swapfile.c
@@ -874,6 +874,48 @@ int page_swapcount(struct page *page)
 	return count;
 }
 
+/*
+ * How many references to @entry are currently swapped out?
+ * This considers COUNT_CONTINUED so it returns exact answer.
+ */
+int swp_swapcount(swp_entry_t entry)
+{
+	int count, tmp_count, n;
+	struct swap_info_struct *p;
+	struct page *page;
+	pgoff_t offset;
+	unsigned char *map;
+
+	p = swap_info_get(entry);
+	if (!p)
+		return 0;
+
+	count = swap_count(p->swap_map[swp_offset(entry)]);
+	if (!(count & COUNT_CONTINUED))
+		goto out;
+
+	count &= ~COUNT_CONTINUED;
+	n = SWAP_MAP_MAX + 1;
+
+	offset = swp_offset(entry);
+	page = vmalloc_to_page(p->swap_map + offset);
+	offset &= ~PAGE_MASK;
+	VM_BUG_ON(page_private(page) != SWP_CONTINUED);
+
+	do {
+		page = list_entry(page->lru.next, struct page, lru);
+		map = kmap_atomic(page);
+		tmp_count = map[offset];
+		kunmap_atomic(map);
+
+		count += (tmp_count & ~COUNT_CONTINUED) * n;
+		n *= (SWAP_CONT_MAX + 1);
+	} while (tmp_count & COUNT_CONTINUED);
+out:
+	spin_unlock(&p->lock);
+	return count;
+}
+
 /*
  * We can write to an anon page without COW if there are no other references
  * to it.  And as a side-effect, free up its swap: because the old content
@@ -2032,7 +2074,7 @@ static int swap_show(struct seq_file *swap, void *v)
 	}
 
 	file = si->swap_file;
-	len = seq_path(swap, &file->f_path, " \t\n\\");
+	len = seq_file_path(swap, file, " \t\n\\");
 	seq_printf(swap, "%*s%s\t%u\t%u\t%d\n",
 			len < 40 ? 40 - len : 1, " ",
 			S_ISBLK(file_inode(file)->i_mode) ?
@@ -2143,11 +2185,10 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode)
 	if (S_ISBLK(inode->i_mode)) {
 		p->bdev = bdgrab(I_BDEV(inode));
 		error = blkdev_get(p->bdev,
-				   FMODE_READ | FMODE_WRITE | FMODE_EXCL,
-				   sys_swapon);
+				   FMODE_READ | FMODE_WRITE | FMODE_EXCL, p);
 		if (error < 0) {
 			p->bdev = NULL;
-			return -EINVAL;
+			return error;
 		}
 		p->old_block_size = block_size(p->bdev);
 		error = set_blocksize(p->bdev, PAGE_SIZE);
@@ -2184,6 +2225,8 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
 		swab32s(&swap_header->info.version);
 		swab32s(&swap_header->info.last_page);
 		swab32s(&swap_header->info.nr_badpages);
+		if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
+			return 0;
 		for (i = 0; i < swap_header->info.nr_badpages; i++)
 			swab32s(&swap_header->info.badpages[i]);
 	}
@@ -2348,7 +2391,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	struct filename *name;
 	struct file *swap_file = NULL;
 	struct address_space *mapping;
-	int i;
 	int prio;
 	int error;
 	union swap_header *swap_header;
@@ -2388,19 +2430,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 
 	p->swap_file = swap_file;
 	mapping = swap_file->f_mapping;
-
-	for (i = 0; i < nr_swapfiles; i++) {
-		struct swap_info_struct *q = swap_info[i];
-
-		if (q == p || !q->swap_file)
-			continue;
-		if (mapping == q->swap_file->f_mapping) {
-			error = -EBUSY;
-			goto bad_swap;
-		}
-	}
-
 	inode = mapping->host;
+
 	/* If S_ISREG(inode->i_mode) will do mutex_lock(&inode->i_mutex); */
 	error = claim_swapfile(p, inode);
 	if (unlikely(error))
@@ -2433,6 +2464,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		goto bad_swap;
 	}
 	if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) {
+		int cpu;
+
 		p->flags |= SWP_SOLIDSTATE;
 		/*
 		 * select a random position to start with to help wear leveling
@@ -2451,9 +2484,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 			error = -ENOMEM;
 			goto bad_swap;
 		}
-		for_each_possible_cpu(i) {
+		for_each_possible_cpu(cpu) {
 			struct percpu_cluster *cluster;
-			cluster = per_cpu_ptr(p->percpu_cluster, i);
+			cluster = per_cpu_ptr(p->percpu_cluster, cpu);
 			cluster_set_null(&cluster->index);
 		}
 	}