[PATCH] Always print out the header line in /proc/swaps

It would be possible for /proc/swaps to not always print out the header:

swapon /dev/hdc2
swapon /dev/hde2
swapoff /dev/hdc2

At this point /proc/swaps would not have a header.

Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 5 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index a15def63f28f..8e206cea0f5e 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1274,10 +1274,13 @@ static void *swap_start(struct seq_file *swap, loff_t *pos)
 
         mutex_lock(&swapon_mutex);
 
+        if (!l)
+                return SEQ_START_TOKEN;
+
         for (i = 0; i < nr_swapfiles; i++, ptr++) {
                 if (!(ptr->flags & SWP_USED) || !ptr->swap_map)
                         continue;
-                if (!l--)
+                if (!--l)
                         return ptr;
         }
 
@@ -1286,10 +1289,17 @@ static void *swap_start(struct seq_file *swap, loff_t *pos)
 
 static void *swap_next(struct seq_file *swap, void *v, loff_t *pos)
 {
-        struct swap_info_struct *ptr = v;
+        struct swap_info_struct *ptr;
         struct swap_info_struct *endptr = swap_info + nr_swapfiles;
 
-        for (++ptr; ptr < endptr; ptr++) {
+        if (v == SEQ_START_TOKEN)
+                ptr = swap_info;
+        else {
+                ptr = v;
+                ptr++;
+        }
+
+        for (; ptr < endptr; ptr++) {
                 if (!(ptr->flags & SWP_USED) || !ptr->swap_map)
                         continue;
                 ++*pos;
@@ -1310,8 +1320,10 @@ static int swap_show(struct seq_file *swap, void *v)
         struct file *file;
         int len;
 
-        if (v == swap_info)
-                seq_puts(swap, "Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n");
+        if (ptr == SEQ_START_TOKEN) {
+                seq_puts(swap,"Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n");
+                return 0;
+        }
 
         file = ptr->swap_file;
         len = seq_path(swap, file->f_vfsmnt, file->f_dentry, " \t\n\\");