diff options
| author | Minchan Kim <minchan@kernel.org> | 2013-05-01 02:26:54 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-01 04:04:00 +0400 |
| commit | 4f89849da22db9d0edb378acea65e23fcd546173 (patch) | |
| tree | 8af95a340c8d8605ad8f492ef0f6f98f2a4e4523 /mm/swapfile.c | |
| parent | f066ea230a65f939afc354beae62716ab5f0e645 (diff) | |
| download | linux-4f89849da22db9d0edb378acea65e23fcd546173.tar.xz | |
frontswap: get rid of swap_lock dependency
Frontswap initialization routine depends on swap_lock, which want to be
atomic about frontswap's first appearance. IOW, frontswap is not present
and will fail all calls OR frontswap is fully functional but if new
swap_info_struct isn't registered by enable_swap_info, swap subsystem
doesn't start I/O so there is no race between init procedure and page I/O
working on frontswap.
So let's remove unnecessary swap_lock dependency.
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
[v1: Rebased on my branch, reworked to work with backends loading late]
[v2: Added a check for !map]
[v3: Made the invalidate path follow the init path]
[v4: Address comments by Wanpeng Li <liwanp@linux.vnet.ibm.com>]
Signed-off-by: Konrad Rzeszutek Wilk <konrad@darnok.org>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index d417efddfe74..6c340d908b27 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1509,8 +1509,7 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) } static void _enable_swap_info(struct swap_info_struct *p, int prio, - unsigned char *swap_map, - unsigned long *frontswap_map) + unsigned char *swap_map) { int i, prev; @@ -1519,7 +1518,6 @@ static void _enable_swap_info(struct swap_info_struct *p, int prio, else p->prio = --least_priority; p->swap_map = swap_map; - frontswap_map_set(p, frontswap_map); p->flags |= SWP_WRITEOK; atomic_long_add(p->pages, &nr_swap_pages); total_swap_pages += p->pages; @@ -1542,10 +1540,10 @@ static void enable_swap_info(struct swap_info_struct *p, int prio, unsigned char *swap_map, unsigned long *frontswap_map) { + frontswap_init(p->type, frontswap_map); spin_lock(&swap_lock); spin_lock(&p->lock); - _enable_swap_info(p, prio, swap_map, frontswap_map); - frontswap_init(p->type); + _enable_swap_info(p, prio, swap_map); spin_unlock(&p->lock); spin_unlock(&swap_lock); } @@ -1554,7 +1552,7 @@ static void reinsert_swap_info(struct swap_info_struct *p) { spin_lock(&swap_lock); spin_lock(&p->lock); - _enable_swap_info(p, p->prio, p->swap_map, frontswap_map_get(p)); + _enable_swap_info(p, p->prio, p->swap_map); spin_unlock(&p->lock); spin_unlock(&swap_lock); } @@ -1563,6 +1561,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) { struct swap_info_struct *p = NULL; unsigned char *swap_map; + unsigned long *frontswap_map; struct file *swap_file, *victim; struct address_space *mapping; struct inode *inode; @@ -1662,12 +1661,14 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) swap_map = p->swap_map; p->swap_map = NULL; p->flags = 0; - frontswap_invalidate_area(type); + frontswap_map = frontswap_map_get(p); + frontswap_map_set(p, NULL); spin_unlock(&p->lock); spin_unlock(&swap_lock); + frontswap_invalidate_area(type); mutex_unlock(&swapon_mutex); vfree(swap_map); - vfree(frontswap_map_get(p)); + vfree(frontswap_map); /* Destroy swap account informatin */ swap_cgroup_swapoff(type); |