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Commit 40531542 authored by Cesar Eduardo Barros's avatar Cesar Eduardo Barros Committed by Linus Torvalds
Browse files

sys_swapon: separate final enabling of the swapfile 



The block in sys_swapon which does the final adjustments to the
swap_info_struct and to swap_list is the same as the block which
re-inserts it again at sys_swapoff on failure of try_to_unuse(). Move
this code to a separate function, and use it both in sys_swapon and
sys_swapoff.

Signed-off-by: default avatarCesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: default avatarEric B Munson <emunson@mgebm.net>
Acked-by: default avatarEric B Munson <emunson@mgebm.net>
Reviewed-by: default avatarPekka Enberg <penberg@kernel.org>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c6a2b64b

mm/swapfile.c

+42 −42
Original line number Diff line number Diff line
@@ -1550,6 +1550,36 @@ bad_bmap: 
	goto out;

}



static void enable_swap_info(struct swap_info_struct *p, int prio,

				unsigned char *swap_map)

{

	int i, prev;



	spin_lock(&swap_lock);

	if (prio >= 0)

		p->prio = prio;

	else

		p->prio = --least_priority;

	p->swap_map = swap_map;

	p->flags |= SWP_WRITEOK;

	nr_swap_pages += p->pages;

	total_swap_pages += p->pages;



	/* insert swap space into swap_list: */

	prev = -1;

	for (i = swap_list.head; i >= 0; i = swap_info[i]->next) {

		if (p->prio >= swap_info[i]->prio)

			break;

		prev = i;

	}

	p->next = i;

	if (prev < 0)

		swap_list.head = swap_list.next = p->type;

	else

		swap_info[prev]->next = p->type;

	spin_unlock(&swap_lock);

}



SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)

{

	struct swap_info_struct *p = NULL;
@@ -1621,26 +1651,14 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) 
	current->flags &= ~PF_OOM_ORIGIN;



	if (err) {

		/*

		 * reading p->prio and p->swap_map outside the lock is

		 * safe here because only sys_swapon and sys_swapoff

		 * change them, and there can be no other sys_swapon or

		 * sys_swapoff for this swap_info_struct at this point.

		 */

		/* re-insert swap space back into swap_list */

		spin_lock(&swap_lock);

		if (p->prio < 0)

			p->prio = --least_priority;

		p->flags |= SWP_WRITEOK;

		nr_swap_pages += p->pages;

		total_swap_pages += p->pages;



		prev = -1;

		for (i = swap_list.head; i >= 0; i = swap_info[i]->next) {

			if (p->prio >= swap_info[i]->prio)

				break;

			prev = i;

		}

		p->next = i;

		if (prev < 0)

			swap_list.head = swap_list.next = type;

		else

			swap_info[prev]->next = type;

		spin_unlock(&swap_lock);

		enable_swap_info(p, p->prio, p->swap_map);

		goto out_dput;

	}
@@ -2037,7 +2055,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) 
	char *name;

	struct file *swap_file = NULL;

	struct address_space *mapping;

	int i, prev;

	int i;

	int prio;

	int error;

	union swap_header *swap_header;

	int nr_extents;
@@ -2134,30 +2153,11 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) 
	}



	mutex_lock(&swapon_mutex);

	spin_lock(&swap_lock);

	prio = -1;

	if (swap_flags & SWAP_FLAG_PREFER)

		p->prio =

		prio =

		  (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT;

	else

		p->prio = --least_priority;

	p->swap_map = swap_map;

	p->flags |= SWP_WRITEOK;

	nr_swap_pages += p->pages;

	total_swap_pages += p->pages;



	/* insert swap space into swap_list: */

	prev = -1;

	for (i = swap_list.head; i >= 0; i = swap_info[i]->next) {

		if (p->prio >= swap_info[i]->prio)

			break;

		prev = i;

	}

	p->next = i;

	if (prev < 0)

		swap_list.head = swap_list.next = p->type;

	else

		swap_info[prev]->next = p->type;

	spin_unlock(&swap_lock);

	enable_swap_info(p, prio, swap_map);



	printk(KERN_INFO "Adding %uk swap on %s.  "

			"Priority:%d extents:%d across:%lluk %s%s\n",