[PATCH] Always print out the header line in /proc/swaps
Suleiman Souhlal [Thu, 7 Dec 2006 04:32:28 +0000 (20:32 -0800)]
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>

mm/swapfile.c

index a15def6..8e206ce 100644 (file)
@@ -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\\");