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.ro...@intel.com>
Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursu...@linux.intel.com>
Cc: David Airlie <airl...@linux.ie>
Cc: Daniel Vetter <dan...@ffwll.ch>
Cc: Matthew Auld <matthew.a...@intel.com>
Cc: Thomas Hellström <thomas.hellst...@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com>
Reviewed-by: Matt Atwood <matthew.s.atw...@intel.com>
---
drivers/gpu/drm/i915/gt/shmem_utils.c | 32 +++++++++++++++++++++++++++
drivers/gpu/drm/i915/gt/shmem_utils.h | 3 +++
2 files changed, 35 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c
b/drivers/gpu/drm/i915/gt/shmem_utils.c
index 0683b27a3890..402f085f3a02 100644
--- a/drivers/gpu/drm/i915/gt/shmem_utils.c
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -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);
diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.h
b/drivers/gpu/drm/i915/gt/shmem_utils.h
index c1669170c351..b2b04d88c6e5 100644
--- a/drivers/gpu/drm/i915/gt/shmem_utils.h
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.h
@@ -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);
--
2.35.1
