From 915bae9ebe41e52d71ad8b06d50e4ab26189f964 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 6 Dec 2006 20:34:07 -0800 Subject: [PATCH] swsusp: use partition device and offset to identify swap areas The Linux kernel handles swap files almost in the same way as it handles swap partitions and there are only two differences between these two types of swap areas: (1) swap files need not be contiguous, (2) the header of a swap file is not in the first block of the partition that holds it. From the swsusp's point of view (1) is not a problem, because it is already taken care of by the swap-handling code, but (2) has to be taken into consideration. In principle the location of a swap file's header may be determined with the help of appropriate filesystem driver. Unfortunately, however, it requires the filesystem holding the swap file to be mounted, and if this filesystem is journaled, it cannot be mounted during a resume from disk. For this reason we need some other means by which swap areas can be identified. For example, to identify a swap area we can use the partition that holds the area and the offset from the beginning of this partition at which the swap header is located. The following patch allows swsusp to identify swap areas this way. It changes swap_type_of() so that it takes an additional argument representing an offset of the swap header within the partition represented by its first argument. Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/swap.c | 2 +- kernel/power/user.c | 5 +++-- 2 files changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel/power') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 1a3b0dd2c3f..7b10da16389 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -74,7 +74,7 @@ static int mark_swapfiles(swp_entry_t start) static int swsusp_swap_check(void) /* This is called before saving image */ { - int res = swap_type_of(swsusp_resume_device); + int res = swap_type_of(swsusp_resume_device, 0); if (res >= 0) { root_swap = res; diff --git a/kernel/power/user.c b/kernel/power/user.c index 4c24ca5d62e..a327b18a5ff 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -55,7 +55,8 @@ static int snapshot_open(struct inode *inode, struct file *filp) filp->private_data = data; memset(&data->handle, 0, sizeof(struct snapshot_handle)); if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { - data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1; + data->swap = swsusp_resume_device ? + swap_type_of(swsusp_resume_device, 0) : -1; data->mode = O_RDONLY; } else { data->swap = -1; @@ -265,7 +266,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp, * so we need to recode them */ if (old_decode_dev(arg)) { - data->swap = swap_type_of(old_decode_dev(arg)); + data->swap = swap_type_of(old_decode_dev(arg), 0); if (data->swap < 0) error = -ENODEV; } else { -- cgit v1.2.3-70-g09d2