Hi again.
On 07/05/10 17:25, Nitin Gupta wrote:
Added SWP_BLKDEV flag to distinguish block and regular file backed
swap devices. We could also check if a swap is entire block device,
rather than a file, by:
S_ISBLK(swap_info_struct->swap_file->f_mapping->host->i_mode)
but, I think, simply checking this flag is more convenient.
Signed-off-by: Nitin Gupta<ngupta@xxxxxxxxxx>
---
include/linux/swap.h | 1 +
mm/swapfile.c | 1 +
2 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 1f59d93..ec2b7a4 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -146,6 +146,7 @@ enum {
SWP_DISCARDING = (1<< 3), /* now discarding a free cluster */
SWP_SOLIDSTATE = (1<< 4), /* blkdev seeks are cheap */
SWP_CONTINUED = (1<< 5), /* swap_map has count continuation */
+ SWP_BLKDEV = (1<< 6), /* its a block device */
/* add others here before... */
SWP_SCANNING = (1<< 8), /* refcount in scan_swap_map */
};
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6cd0a8f..ecb069e 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1884,6 +1884,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
if (error< 0)
goto bad_swap;
p->bdev = bdev;
+ p->flags |= SWP_BLKDEV;
} else if (S_ISREG(inode->i_mode)) {
p->bdev = inode->i_sb->s_bdev;
mutex_lock(&inode->i_mutex);
The more I read your patches, the more I think either I'm seriously
confused (entirely possible!) or you are.
Don't you want to distinguish RAM backed swap from swap that's either a
partition or a file? If that's the case, you should also be setting
SWP_BLKDEV in the S_ISREG part that follows iff the p->bdev is a regular
file.
Regards,
Nigel
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