Add a variant of shmem_read() that takes a dma_buf_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 dma_buf_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.
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: Lucas De Marchi lucas.demarchi@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..d7968e68ccfb 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/dma-buf-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_dma_buf_map(struct file *file, loff_t off, + struct dma_buf_map *map, size_t len) +{ + struct dma_buf_map map_iter = *map; + 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); + dma_buf_map_memcpy_to(&map_iter, vaddr + offset_in_page(off), this); + mark_page_accessed(page); + kunmap(page); + put_page(page); + + len -= this; + dma_buf_map_incr(&map_iter, 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..a3d4ce966f74 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 dma_buf_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_dma_buf_map(struct file *file, loff_t off, + struct dma_buf_map *map, 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);