linux-kernel - [PATCH 2/2] drm: Use vmap_file() in shmem_pin

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Message-ID: <20250131001806.92349-3-vishal.moola@gmail.com>
Date: Thu, 30 Jan 2025 16:18:06 -0800
From: "Vishal Moola (Oracle)" <vishal.moola@...il.com>
To: akpm@...ux-foundation.org
Cc: linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	hch@...radead.org,
	urezki@...il.com,
	intel-gfx@...ts.freedesktop.org,
	"Vishal Moola (Oracle)" <vishal.moola@...il.com>
Subject: [PATCH 2/2] drm: Use vmap_file() in shmem_pin_map()

We no longer need to allocate a new array of pages to map this file
to kernel virtual space. This simplifies shmem_pin_map(), and gets rid
of a user of VM_MAP_PUT_PAGES.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@...il.com>
---
 drivers/gpu/drm/i915/gt/shmem_utils.c | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c b/drivers/gpu/drm/i915/gt/shmem_utils.c
index bb696b29ee2c..79d930ed5229 100644
--- a/drivers/gpu/drm/i915/gt/shmem_utils.c
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -57,32 +57,15 @@ struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
 
 void *shmem_pin_map(struct file *file)
 {
-	struct page **pages;
-	size_t n_pages, i;
 	void *vaddr;
 
-	n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
-	pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
-	if (!pages)
-		return NULL;
-
-	for (i = 0; i < n_pages; i++) {
-		pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
-						       GFP_KERNEL);
-		if (IS_ERR(pages[i]))
-			goto err_page;
-	}
+	vaddr = vmap_file(file->f_mapping, 0, file->f_mapping->host->i_size,
+			VM_MAP, PAGE_KERNEL);
 
-	vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
 	if (!vaddr)
-		goto err_page;
+		return NULL;
 	mapping_set_unevictable(file->f_mapping);
 	return vaddr;
-err_page:
-	while (i--)
-		put_page(pages[i]);
-	kvfree(pages);
-	return NULL;
 }
 
 void shmem_unpin_map(struct file *file, void *ptr)
-- 
2.47.1