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>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 5238d8d15d78f9488a6122da697039490c114fba..6d1c3c67ae65d5ddf37647fdc36ab91a1762f570 100644 (file)
--- 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)) {