Merge branch 'fix/kconfig' into for-linus

1 files changed, 21 insertions, 30 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index d537d29e9b7..17bc224bce6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -14,7 +14,7 @@
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/namei.h>
-#include <linux/shm.h>
+#include <linux/shmem_fs.h>
 #include <linux/blkdev.h>
 #include <linux/random.h>
 #include <linux/writeback.h>
@@ -1681,19 +1681,14 @@ 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;
+	struct seq_file *seq = 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);
+	if (seq->poll_event != atomic_read(&proc_poll_event)) {
+		seq->poll_event = atomic_read(&proc_poll_event);
 		return POLLIN | POLLRDNORM | POLLERR | POLLPRI;
 	}
 
@@ -1783,24 +1778,16 @@ static const struct seq_operations swaps_op = {
 
 static int swaps_open(struct inode *inode, struct file *file)
 {
-	struct proc_swaps *s;
+	struct seq_file *seq;
 	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);
+	if (ret)
 		return ret;
-	}
 
-	s->seq.private = s;
-	s->event = atomic_read(&proc_poll_event);
-	return ret;
+	seq = file->private_data;
+	seq->poll_event = atomic_read(&proc_poll_event);
+	return 0;
 }
 
 static const struct file_operations proc_swaps_operations = {
@@ -1937,20 +1924,24 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
 
 	/*
 	 * Find out how many pages are allowed for a single swap
-	 * device. There are two limiting factors: 1) the number of
-	 * bits for the swap offset in the swp_entry_t type and
-	 * 2) the number of bits in the a swap pte as defined by
-	 * the different architectures. In order to find the
-	 * largest possible bit mask a swap entry with swap type 0
+	 * device. There are three limiting factors: 1) the number
+	 * of bits for the swap offset in the swp_entry_t type, and
+	 * 2) the number of bits in the swap pte as defined by the
+	 * the different architectures, and 3) the number of free bits
+	 * in an exceptional radix_tree entry. In order to find the
+	 * largest possible bit mask, a swap entry with swap type 0
 	 * and swap offset ~0UL is created, encoded to a swap pte,
-	 * decoded to a swp_entry_t again and finally the swap
+	 * decoded to a swp_entry_t again, and finally the swap
 	 * offset is extracted. This will mask all the bits from
 	 * the initial ~0UL mask that can't be encoded in either
 	 * the swp_entry_t or the architecture definition of a
-	 * swap pte.
+	 * swap pte.  Then the same is done for a radix_tree entry.
 	 */
 	maxpages = swp_offset(pte_to_swp_entry(
-			swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+			swp_entry_to_pte(swp_entry(0, ~0UL))));
+	maxpages = swp_offset(radix_to_swp_entry(
+			swp_to_radix_entry(swp_entry(0, maxpages)))) + 1;
+
 	if (maxpages > swap_header->info.last_page) {
 		maxpages = swap_header->info.last_page + 1;
 		/* p->max is an unsigned int: don't overflow it */