Commit 9659dd2b authored by Lucas De Marchi's avatar Lucas De Marchi
Browse files

drm/i915/gt: Add helper for shmem copy to iosys_map 



Add a variant of shmem_read() that takes a iosys_map pointer rather
than a plain pointer as argument. It's mostly a copy __shmem_rw() but
adapting the api and removing the write support since there's currently
only need to use iosys_map as destination.

Reworking __shmem_rw() to share the implementation was tempting, but
finding a good balance between reuse and clarity pushed towards a little
code duplication. Since the function is small, just add the similar
function with a copy/paste/adapt approach.

v2: Add an offset as argument and instead of using a map iterator, use the
offset to keep track of where we are writing data to.

Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: default avatarMatt Atwood <matthew.s.atwood@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220216174147.3073235-4-lucas.demarchi@intel.com
parent 1be6b46f

drivers/gpu/drm/i915/gt/shmem_utils.c

+32 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
 * Copyright © 2020 Intel Corporation

 */



#include <linux/iosys-map.h>

#include <linux/mm.h>

#include <linux/pagemap.h>

#include <linux/shmem_fs.h>
@@ -123,6 +124,37 @@ static int __shmem_rw(struct file *file, loff_t off, 
	return 0;

}



int shmem_read_to_iosys_map(struct file *file, loff_t off,

			    struct iosys_map *map, size_t map_off, size_t len)

{

	unsigned long pfn;



	for (pfn = off >> PAGE_SHIFT; len; pfn++) {

		unsigned int this =

			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);

		struct page *page;

		void *vaddr;



		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,

						   GFP_KERNEL);

		if (IS_ERR(page))

			return PTR_ERR(page);



		vaddr = kmap(page);

		iosys_map_memcpy_to(map, map_off, vaddr + offset_in_page(off),

				    this);

		mark_page_accessed(page);

		kunmap(page);

		put_page(page);



		len -= this;

		map_off += this;

		off = 0;

	}



	return 0;

}



int shmem_read(struct file *file, loff_t off, void *dst, size_t len)

{

	return __shmem_rw(file, off, dst, len, false);

drivers/gpu/drm/i915/gt/shmem_utils.h

+3 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 


#include <linux/types.h>



struct iosys_map;

struct drm_i915_gem_object;

struct file;
@@ -17,6 +18,8 @@ struct file *shmem_create_from_object(struct drm_i915_gem_object *obj); 
void *shmem_pin_map(struct file *file);

void shmem_unpin_map(struct file *file, void *ptr);



int shmem_read_to_iosys_map(struct file *file, loff_t off,

			    struct iosys_map *map, size_t map_off, size_t len);

int shmem_read(struct file *file, loff_t off, void *dst, size_t len);

int shmem_write(struct file *file, loff_t off, void *src, size_t len);