From 6e1819d615f24ce0726a7d0bd3dd0152d7b21654 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 23 Mar 2006 03:00:03 -0800 Subject: [PATCH] swsusp: userland interface MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch introduces a user space interface for swsusp. The interface is based on a special character device, called the snapshot device, that allows user space processes to perform suspend and resume-related operations with the help of some ioctls and the read()/write() functions.  Additionally it allows these processes to allocate free swap pages from a selected swap partition, called the resume partition, so that they know which sectors of the resume partition are available to them. The interface uses the same low-level system memory snapshot-handling functions that are used by the built-it swap-writing/reading code of swsusp. The interface documentation is included in the patch. The patch assumes that the major and minor numbers of the snapshot device will be 10 (ie. misc device) and 231, the registration of which has already been requested. Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swapfile.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'mm') diff --git a/mm/swapfile.c b/mm/swapfile.c index 4d11f9d84666..39aa9d129612 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -428,14 +428,16 @@ int swap_type_of(dev_t device) { int i; - if (!device) - return -EINVAL; spin_lock(&swap_lock); for (i = 0; i < nr_swapfiles; i++) { struct inode *inode; if (!(swap_info[i].flags & SWP_WRITEOK)) continue; + if (!device) { + spin_unlock(&swap_lock); + return i; + } inode = swap_info->swap_file->f_dentry->d_inode; if (S_ISBLK(inode->i_mode) && device == MKDEV(imajor(inode), iminor(inode))) { -- cgit v1.2.1