sys_swapon: separate swap_info allocation

Move the swap_info allocation to its own function. Only code movement,
no functional changes.

Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 37 insertions, 20 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 5238d8d15d78..6d1c3c67ae65 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1844,33 +1844,15 @@ static int __init max_swapfiles_check(void)
 late_initcall(max_swapfiles_check);
 #endif
 
-SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
+static struct swap_info_struct *alloc_swap_info(void)
 {
         struct swap_info_struct *p;
-        char *name = NULL;
-        struct block_device *bdev = NULL;
-        struct file *swap_file = NULL;
-        struct address_space *mapping;
         unsigned int type;
-        int i, prev;
         int error;
-        union swap_header *swap_header;
-        unsigned int nr_good_pages;
-        int nr_extents = 0;
-        sector_t span;
-        unsigned long maxpages;
-        unsigned long swapfilepages;
-        unsigned char *swap_map = NULL;
-        struct page *page = NULL;
-        struct inode *inode = NULL;
-        int did_down = 0;
-
-        if (!capable(CAP_SYS_ADMIN))
-                return -EPERM;
 
         p = kzalloc(sizeof(*p), GFP_KERNEL);
         if (!p)
-                return -ENOMEM;
+                return ERR_PTR(-ENOMEM);
 
         spin_lock(&swap_lock);
         for (type = 0; type < nr_swapfiles; type++) {
@@ -1906,6 +1888,41 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
         p->next = -1;
         spin_unlock(&swap_lock);
 
+        return p;
+
+out:
+        return ERR_PTR(error);
+}
+
+SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
+{
+        struct swap_info_struct *p;
+        char *name = NULL;
+        struct block_device *bdev = NULL;
+        struct file *swap_file = NULL;
+        struct address_space *mapping;
+        int i, prev;
+        int error;
+        union swap_header *swap_header;
+        unsigned int nr_good_pages;
+        int nr_extents = 0;
+        sector_t span;
+        unsigned long maxpages;
+        unsigned long swapfilepages;
+        unsigned char *swap_map = NULL;
+        struct page *page = NULL;
+        struct inode *inode = NULL;
+        int did_down = 0;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        p = alloc_swap_info();
+        if (IS_ERR(p)) {
+                error = PTR_ERR(p);
+                goto out;
+        }
+
         name = getname(specialfile);
         error = PTR_ERR(name);
         if (IS_ERR(name)) {