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e7b5d23e5d
Provide a standalone shmem backup implementation. Given the ttm_backup interface, this could later on be extended to providing other backup implementation than shmem, with one use-case being GPU swapout to a user-provided fd. v5: - Fix a UAF. (kernel test robot, Dan Carptenter) v6: - Rename ttm_backup_shmem_copy_page() function argument (Matthew Brost) - Add some missing documentation v8: - Use folio_file_page to get to the page we want to writeback instead of using the first page of the folio. v13: - Remove the base class abstraction (Christian König) - Include ttm_backup_bytes_avail(). v14: - Fix kerneldoc for ttm_backup_bytes_avail() (0-day) - Work around casting of __randomize_layout struct pointer (0-day) v15: - Return negative error code from ttm_backup_backup_page() (Christian König) - Doc fixes. (Christian König). Cc: Christian König <christian.koenig@amd.com> Cc: Somalapuram Amaranath <Amaranath.Somalapuram@amd.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: <dri-devel@lists.freedesktop.org> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> Reviewed-by: Matthew Brost <matthew.brost@intel.com> Reviewed-by: Christian König <christian.koenig@amd.com> Link: https://lore.kernel.org/intel-xe/20250305092220.123405-2-thomas.hellstrom@linux.intel.com
75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
/* SPDX-License-Identifier: MIT */
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/*
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* Copyright © 2024 Intel Corporation
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*/
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#ifndef _TTM_BACKUP_H_
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#define _TTM_BACKUP_H_
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#include <linux/mm_types.h>
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#include <linux/shmem_fs.h>
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struct ttm_backup;
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/**
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* ttm_backup_handle_to_page_ptr() - Convert handle to struct page pointer
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* @handle: The handle to convert.
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*
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* Converts an opaque handle received from the
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* struct ttm_backoup_ops::backup_page() function to an (invalid)
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* struct page pointer suitable for a struct page array.
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*
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* Return: An (invalid) struct page pointer.
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*/
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static inline struct page *
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ttm_backup_handle_to_page_ptr(unsigned long handle)
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{
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return (struct page *)(handle << 1 | 1);
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}
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/**
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* ttm_backup_page_ptr_is_handle() - Whether a struct page pointer is a handle
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* @page: The struct page pointer to check.
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*
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* Return: true if the struct page pointer is a handld returned from
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* ttm_backup_handle_to_page_ptr(). False otherwise.
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*/
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static inline bool ttm_backup_page_ptr_is_handle(const struct page *page)
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{
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return (unsigned long)page & 1;
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}
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/**
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* ttm_backup_page_ptr_to_handle() - Convert a struct page pointer to a handle
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* @page: The struct page pointer to convert
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*
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* Return: The handle that was previously used in
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* ttm_backup_handle_to_page_ptr() to obtain a struct page pointer, suitable
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* for use as argument in the struct ttm_backup_ops drop() or
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* copy_backed_up_page() functions.
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*/
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static inline unsigned long
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ttm_backup_page_ptr_to_handle(const struct page *page)
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{
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WARN_ON(!ttm_backup_page_ptr_is_handle(page));
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return (unsigned long)page >> 1;
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}
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void ttm_backup_drop(struct ttm_backup *backup, pgoff_t handle);
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int ttm_backup_copy_page(struct ttm_backup *backup, struct page *dst,
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pgoff_t handle, bool intr);
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s64
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ttm_backup_backup_page(struct ttm_backup *backup, struct page *page,
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bool writeback, pgoff_t idx, gfp_t page_gfp,
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gfp_t alloc_gfp);
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void ttm_backup_fini(struct ttm_backup *backup);
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u64 ttm_backup_bytes_avail(void);
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struct ttm_backup *ttm_backup_shmem_create(loff_t size);
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#endif
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