drm/ttm/ttm_backup.c

1 // SPDX-License-Identifier: MIT
7 #include <linux/page-flags.h>
21 	return handle - 1;  in ttm_backup_handle_to_shmem_idx()
25  * ttm_backup_drop() - release memory associated with a handle
31 	loff_t start = ttm_backup_handle_to_shmem_idx(handle);  in ttm_backup_drop()  local
33 	start <<= PAGE_SHIFT;  in ttm_backup_drop()
34 	shmem_truncate_range(file_inode(backup), start,  in ttm_backup_drop()
35 			     start + PAGE_SIZE - 1);  in ttm_backup_drop()
39  * ttm_backup_copy_page() - Copy the contents of a previously backed
40  * up page
41  * @backup: The struct backup pointer used to back up the page.
43  * @handle: The handle returned when the page was backed up.
47  * -EINTR if @intr was set to true and a signal is pending.
52 	struct address_space *mapping = backup->f_mapping;  in ttm_backup_copy_page()
67  * ttm_backup_backup_page() - Backup a page
69  * @page: The page to back up.
84  * we're not allowed to start backup IO.
88  * Note: This function could be extended to back up a folio and
91  * the folio size- and usage.
98 	struct address_space *mapping = backup->f_mapping;  in ttm_backup_backup_page()
123 		ret = mapping->a_ops->writepage(folio_file_page(to_folio, idx), &wbc);  in ttm_backup_backup_page()
143  * ttm_backup_fini() - Free the struct backup resources after last use.
154  * ttm_backup_bytes_avail() - Report the approximate number of bytes of backup space
165 	 * The idea behind backing up to shmem is that shmem objects may  in ttm_backup_bytes_avail()
167 	 * is no or low swap-space available. But the accuracy of this  in ttm_backup_bytes_avail()
168 	 * number also depends on shmem actually swapping out backed-up  in ttm_backup_bytes_avail()
176  * ttm_backup_shmem_create() - Create a shmem-based struct backup.
177  * @size: The maximum size (in bytes) to back up.