drm/i915: use shmem_read_mapping_page

Soon tmpfs will stop supporting ->readpage and read_cache_page_gfp(): once
"tmpfs: add shmem_read_mapping_page_gfp" has been applied, this patch can
be applied to ease the transition.

Make i915_gem_object_get_pages_gtt() use shmem_read_mapping_page_gfp() in
the one place it's needed; elsewhere use shmem_read_mapping_page(), with
the mapping's gfp_mask properly initialized.

Forget about __GFP_COLD: since tmpfs initializes its pages with memset,
asking for a cold page is counter-productive.

Include linux/shmem_fs.h also in drm_gem.c: with shmem_file_setup() now
declared there too, we shall remove the prototype from linux/mm.h later.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Keith Packard <keithp@keithp.com>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpu/drm/drm_gem.c

@@ -34,6 +34,7 @@
 #include <linux/module.h>
 #include <linux/mman.h>
 #include <linux/pagemap.h>
+#include <linux/shmem_fs.h>
 #include "drmP.h"
 
 /** @file drm_gem.c

drivers/gpu/drm/i915/i915_gem.c

@@ -31,6 +31,7 @@
 #include "i915_drv.h"
 #include "i915_trace.h"
 #include "intel_drv.h"
+#include <linux/shmem_fs.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/pci.h>
@@ -359,8 +360,7 @@ i915_gem_shmem_pread_fast(struct drm_device *dev,
 		if ((page_offset + remain) > PAGE_SIZE)
 			page_length = PAGE_SIZE - page_offset;
 
-		page = read_cache_page_gfp(mapping, offset >> PAGE_SHIFT,
-					   GFP_HIGHUSER | __GFP_RECLAIMABLE);
+		page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
@@ -463,8 +463,7 @@ i915_gem_shmem_pread_slow(struct drm_device *dev,
 		if ((data_page_offset + page_length) > PAGE_SIZE)
 			page_length = PAGE_SIZE - data_page_offset;
 
-		page = read_cache_page_gfp(mapping, offset >> PAGE_SHIFT,
-					   GFP_HIGHUSER | __GFP_RECLAIMABLE);
+		page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
 		if (IS_ERR(page)) {
 			ret = PTR_ERR(page);
 			goto out;
@@ -797,8 +796,7 @@ i915_gem_shmem_pwrite_fast(struct drm_device *dev,
 		if ((page_offset + remain) > PAGE_SIZE)
 			page_length = PAGE_SIZE - page_offset;
 
-		page = read_cache_page_gfp(mapping, offset >> PAGE_SHIFT,
-					   GFP_HIGHUSER | __GFP_RECLAIMABLE);
+		page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
@@ -907,8 +905,7 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev,
 		if ((data_page_offset + page_length) > PAGE_SIZE)
 			page_length = PAGE_SIZE - data_page_offset;
 
-		page = read_cache_page_gfp(mapping, offset >> PAGE_SHIFT,
-					   GFP_HIGHUSER | __GFP_RECLAIMABLE);
+		page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
 		if (IS_ERR(page)) {
 			ret = PTR_ERR(page);
 			goto out;
@@ -1558,12 +1555,10 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj,
 
 	inode = obj->base.filp->f_path.dentry->d_inode;
 	mapping = inode->i_mapping;
+	gfpmask |= mapping_gfp_mask(mapping);
+
 	for (i = 0; i < page_count; i++) {
-		page = read_cache_page_gfp(mapping, i,
-					   GFP_HIGHUSER |
-					   __GFP_COLD |
-					   __GFP_RECLAIMABLE |
-					   gfpmask);
+		page = shmem_read_mapping_page_gfp(mapping, i, gfpmask);
 		if (IS_ERR(page))
 			goto err_pages;
 
@@ -3565,6 +3560,7 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
+	struct address_space *mapping;
 
 	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
 	if (obj == NULL)
@@ -3575,6 +3571,9 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 		return NULL;
 	}
 
+	mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping;
+	mapping_set_gfp_mask(mapping, GFP_HIGHUSER | __GFP_RECLAIMABLE);
+
 	i915_gem_info_add_obj(dev_priv, size);
 
 	obj->base.write_domain = I915_GEM_DOMAIN_CPU;
@@ -3950,8 +3949,7 @@ void i915_gem_detach_phys_object(struct drm_device *dev,
 
 	page_count = obj->base.size / PAGE_SIZE;
 	for (i = 0; i < page_count; i++) {
-		struct page *page = read_cache_page_gfp(mapping, i,
-							GFP_HIGHUSER | __GFP_RECLAIMABLE);
+		struct page *page = shmem_read_mapping_page(mapping, i);
 		if (!IS_ERR(page)) {
 			char *dst = kmap_atomic(page);
 			memcpy(dst, vaddr + i*PAGE_SIZE, PAGE_SIZE);
@@ -4012,8 +4010,7 @@ i915_gem_attach_phys_object(struct drm_device *dev,
 		struct page *page;
 		char *dst, *src;
 
-		page = read_cache_page_gfp(mapping, i,
-					   GFP_HIGHUSER | __GFP_RECLAIMABLE);
+		page = shmem_read_mapping_page(mapping, i);
 		if (IS_ERR(page))
 			return PTR_ERR(page);