Commit d4ad53ad authored by Thomas Hellström's avatar Thomas Hellström
Browse files

drm/ttm: Remove the struct ttm_backup abstraction 



The abstraction was previously added to support separate
ttm_backup implementations.

However with the current implementation casting from a
struct file to a struct ttm_backup, we run into trouble since
struct file may have randomized the layout and gcc complains.

Remove the struct ttm_backup abstraction

Cc: dri-devel@lists.freedesktop.org
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: default avatarKees Cook <kees@kernel.org>
Closes: https://lore.kernel.org/dri-devel/9c8dbbafdaf9f3f089da2cde5a772d69579b3795.camel@linux.intel.com/T/#mb153ab9216cb813b92bdeb36f391ad4808c2ba29


Suggested-by: default avatarChristian König <christian.koenig@amd.com>
Fixes: 70d645de ("drm/ttm: Add helpers for shrinking")
Signed-off-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20250502130014.3156-1-thomas.hellstrom@linux.intel.com
parent 2bb04ea9

drivers/gpu/drm/ttm/ttm_backup.c

+11 −31
Original line number Diff line number Diff line
@@ -7,20 +7,6 @@ 
#include <linux/page-flags.h>

#include <linux/swap.h>



/*

 * Casting from randomized struct file * to struct ttm_backup * is fine since

 * struct ttm_backup is never defined nor dereferenced.

 */

static struct file *ttm_backup_to_file(struct ttm_backup *backup)

{

	return (void *)backup;

}



static struct ttm_backup *ttm_file_to_backup(struct file *file)

{

	return (void *)file;

}



/*

 * Need to map shmem indices to handle since a handle value

 * of 0 means error, following the swp_entry_t convention.
@@ -40,12 +26,12 @@ static pgoff_t ttm_backup_handle_to_shmem_idx(pgoff_t handle) 
 * @backup: The struct backup pointer used to obtain the handle

 * @handle: The handle obtained from the @backup_page function.

 */

void ttm_backup_drop(struct ttm_backup *backup, pgoff_t handle)

void ttm_backup_drop(struct file *backup, pgoff_t handle)

{

	loff_t start = ttm_backup_handle_to_shmem_idx(handle);



	start <<= PAGE_SHIFT;

	shmem_truncate_range(file_inode(ttm_backup_to_file(backup)), start,

	shmem_truncate_range(file_inode(backup), start,

			     start + PAGE_SIZE - 1);

}
@@ -60,11 +46,10 @@ void ttm_backup_drop(struct ttm_backup *backup, pgoff_t handle) 
 * Return: 0 on success, Negative error code on failure, notably

 * -EINTR if @intr was set to true and a signal is pending.

 */

int ttm_backup_copy_page(struct ttm_backup *backup, struct page *dst,

int ttm_backup_copy_page(struct file *backup, struct page *dst,

			 pgoff_t handle, bool intr)

{

	struct file *filp = ttm_backup_to_file(backup);

	struct address_space *mapping = filp->f_mapping;

	struct address_space *mapping = backup->f_mapping;

	struct folio *from_folio;

	pgoff_t idx = ttm_backup_handle_to_shmem_idx(handle);
@@ -106,12 +91,11 @@ int ttm_backup_copy_page(struct ttm_backup *backup, struct page *dst, 
 * the folio size- and usage.

 */

s64

ttm_backup_backup_page(struct ttm_backup *backup, struct page *page,

ttm_backup_backup_page(struct file *backup, struct page *page,

		       bool writeback, pgoff_t idx, gfp_t page_gfp,

		       gfp_t alloc_gfp)

{

	struct file *filp = ttm_backup_to_file(backup);

	struct address_space *mapping = filp->f_mapping;

	struct address_space *mapping = backup->f_mapping;

	unsigned long handle = 0;

	struct folio *to_folio;

	int ret;
@@ -161,9 +145,9 @@ ttm_backup_backup_page(struct ttm_backup *backup, struct page *page, 
 *

 * After a call to this function, it's illegal to use the @backup pointer.

 */

void ttm_backup_fini(struct ttm_backup *backup)

void ttm_backup_fini(struct file *backup)

{

	fput(ttm_backup_to_file(backup));

	fput(backup);

}



/**
@@ -194,14 +178,10 @@ EXPORT_SYMBOL_GPL(ttm_backup_bytes_avail); 
 *

 * Create a backup utilizing shmem objects.

 *

 * Return: A pointer to a struct ttm_backup on success,

 * Return: A pointer to a struct file on success,

 * an error pointer on error.

 */

struct ttm_backup *ttm_backup_shmem_create(loff_t size)

struct file *ttm_backup_shmem_create(loff_t size)

{

	struct file *filp;



	filp = shmem_file_setup("ttm shmem backup", size, 0);



	return ttm_file_to_backup(filp);

	return shmem_file_setup("ttm shmem backup", size, 0);

}

drivers/gpu/drm/ttm/ttm_pool.c

+3 −3
Original line number Diff line number Diff line
@@ -506,7 +506,7 @@ static void ttm_pool_allocated_page_commit(struct page *allocated, 
 * if successful, populate the page-table and dma-address arrays.

 */

static int ttm_pool_restore_commit(struct ttm_pool_tt_restore *restore,

				   struct ttm_backup *backup,

				   struct file *backup,

				   const struct ttm_operation_ctx *ctx,

				   struct ttm_pool_alloc_state *alloc)
@@ -655,7 +655,7 @@ static void ttm_pool_free_range(struct ttm_pool *pool, struct ttm_tt *tt, 
				pgoff_t start_page, pgoff_t end_page)

{

	struct page **pages = &tt->pages[start_page];

	struct ttm_backup *backup = tt->backup;

	struct file *backup = tt->backup;

	pgoff_t i, nr;



	for (i = start_page; i < end_page; i += nr, pages += nr) {
@@ -963,7 +963,7 @@ void ttm_pool_drop_backed_up(struct ttm_tt *tt) 
long ttm_pool_backup(struct ttm_pool *pool, struct ttm_tt *tt,

		     const struct ttm_backup_flags *flags)

{

	struct ttm_backup *backup = tt->backup;

	struct file *backup = tt->backup;

	struct page *page;

	unsigned long handle;

	gfp_t alloc_gfp;

drivers/gpu/drm/ttm/ttm_tt.c

+1 −1
Original line number Diff line number Diff line
@@ -544,7 +544,7 @@ EXPORT_SYMBOL(ttm_tt_pages_limit); 
 */

int ttm_tt_setup_backup(struct ttm_tt *tt)

{

	struct ttm_backup *backup =

	struct file *backup =

		ttm_backup_shmem_create(((loff_t)tt->num_pages) << PAGE_SHIFT);



	if (WARN_ON_ONCE(!(tt->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE)))

include/drm/ttm/ttm_backup.h

+5 −7
Original line number Diff line number Diff line
@@ -9,8 +9,6 @@ 
#include <linux/mm_types.h>

#include <linux/shmem_fs.h>



struct ttm_backup;



/**

 * ttm_backup_handle_to_page_ptr() - Convert handle to struct page pointer

 * @handle: The handle to convert.
@@ -55,20 +53,20 @@ ttm_backup_page_ptr_to_handle(const struct page *page) 
	return (unsigned long)page >> 1;

}



void ttm_backup_drop(struct ttm_backup *backup, pgoff_t handle);

void ttm_backup_drop(struct file *backup, pgoff_t handle);



int ttm_backup_copy_page(struct ttm_backup *backup, struct page *dst,

int ttm_backup_copy_page(struct file *backup, struct page *dst,

			 pgoff_t handle, bool intr);



s64

ttm_backup_backup_page(struct ttm_backup *backup, struct page *page,

ttm_backup_backup_page(struct file *backup, struct page *page,

		       bool writeback, pgoff_t idx, gfp_t page_gfp,

		       gfp_t alloc_gfp);



void ttm_backup_fini(struct ttm_backup *backup);

void ttm_backup_fini(struct file *backup);



u64 ttm_backup_bytes_avail(void);



struct ttm_backup *ttm_backup_shmem_create(loff_t size);

struct file *ttm_backup_shmem_create(loff_t size);



#endif

include/drm/ttm/ttm_tt.h

+1 −1
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ struct ttm_tt { 
	 * ttm_tt_create() callback is responsible for assigning

	 * this field.

	 */

	struct ttm_backup *backup;

	struct file *backup;

	/**

	 * @caching: The current caching state of the pages, see enum

	 * ttm_caching.