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Subject[PATCHv2 13/24] sys_swapon: separate bdev claim and inode lock
Date
Move the code which claims the bdev (S_ISBLK) or locks the inode
(S_ISREG) to a separate 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>
---
mm/swapfile.c | 64 ++++++++++++++++++++++++++++++++++----------------------
1 files changed, 39 insertions(+), 25 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 96be104..27faeec 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1889,6 +1889,43 @@ static struct swap_info_struct *alloc_swap_info(void)
return p;
}

+static int claim_swapfile(struct swap_info_struct *p, struct inode *inode)
+{
+ int error;
+
+ if (S_ISBLK(inode->i_mode)) {
+ p->bdev = bdgrab(I_BDEV(inode));
+ error = blkdev_get(p->bdev,
+ FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+ sys_swapon);
+ if (error < 0) {
+ p->bdev = NULL;
+ error = -EINVAL;
+ goto bad_swap;
+ }
+ p->old_block_size = block_size(p->bdev);
+ error = set_blocksize(p->bdev, PAGE_SIZE);
+ if (error < 0)
+ goto bad_swap;
+ p->flags |= SWP_BLKDEV;
+ } else if (S_ISREG(inode->i_mode)) {
+ p->bdev = inode->i_sb->s_bdev;
+ mutex_lock(&inode->i_mutex);
+ if (IS_SWAPFILE(inode)) {
+ error = -EBUSY;
+ goto bad_swap;
+ }
+ } else {
+ error = -EINVAL;
+ goto bad_swap;
+ }
+
+ return 0;
+
+bad_swap:
+ return error;
+}
+
SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
{
struct swap_info_struct *p;
@@ -1942,32 +1979,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
}
}

- if (S_ISBLK(inode->i_mode)) {
- p->bdev = bdgrab(I_BDEV(inode));
- error = blkdev_get(p->bdev,
- FMODE_READ | FMODE_WRITE | FMODE_EXCL,
- sys_swapon);
- if (error < 0) {
- p->bdev = NULL;
- error = -EINVAL;
- goto bad_swap;
- }
- p->old_block_size = block_size(p->bdev);
- error = set_blocksize(p->bdev, PAGE_SIZE);
- if (error < 0)
- goto bad_swap;
- p->flags |= SWP_BLKDEV;
- } else if (S_ISREG(inode->i_mode)) {
- p->bdev = inode->i_sb->s_bdev;
- mutex_lock(&inode->i_mutex);
- if (IS_SWAPFILE(inode)) {
- error = -EBUSY;
- goto bad_swap;
- }
- } else {
- error = -EINVAL;
+ error = claim_swapfile(p, inode);
+ if (unlikely(error))
goto bad_swap;
- }

swapfilepages = i_size_read(inode) >> PAGE_SHIFT;

--
1.7.4


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