drm: Remove PageReserved manipulation from drm_pci_alloc

drm_pci_alloc/drm_pci_free are very thin wrappers around the core dma
facilities, and we have no special reason within the drm layer to behave
differently. In particular, since

commit de09d31dd38a50fdce106c15abd68432eebbd014
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date:   Fri Jan 15 16:51:42 2016 -0800

    page-flags: define PG_reserved behavior on compound pages

    As far as I can see there's no users of PG_reserved on compound pages.
    Let's use PF_NO_COMPOUND here.

it has been illegal to combine GFP_COMP with SetPageReserved, so lets
stop doing both and leave the dma layer to its own devices.

Reported-by: Taketo Kabe
Bug: https://gitlab.freedesktop.org/drm/intel/issues/1027
Fixes: de09d31dd38a ("page-flags: define PG_reserved behavior on compound pages")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: <stable@vger.kernel.org> # v4.5+
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200202171635.4039044-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c
index f2e43d3..d16dac4 100644 (file)
--- a/drivers/gpu/drm/drm_pci.c
+++ b/drivers/gpu/drm/drm_pci.c
@@ -51,8 +51,6 @@
 drm_dma_handle_t *drm_pci_alloc(struct drm_device * dev, size_t size, size_t align)
 {
        drm_dma_handle_t *dmah;
-       unsigned long addr;
-       size_t sz;
 
        /* pci_alloc_consistent only guarantees alignment to the smallest
         * PAGE_SIZE order which is greater than or equal to the requested size.
@@ -68,20 +66,13 @@ drm_dma_handle_t *drm_pci_alloc(struct drm_device * dev, size_t size, size_t ali
        dmah->size = size;
        dmah->vaddr = dma_alloc_coherent(&dev->pdev->dev, size,
                                         &dmah->busaddr,
-                                        GFP_KERNEL | __GFP_COMP);
+                                        GFP_KERNEL);
 
        if (dmah->vaddr == NULL) {
                kfree(dmah);
                return NULL;
        }
 
-       /* XXX - Is virt_to_page() legal for consistent mem? */
-       /* Reserve */
-       for (addr = (unsigned long)dmah->vaddr, sz = size;
-            sz > 0; addr += PAGE_SIZE, sz -= PAGE_SIZE) {
-               SetPageReserved(virt_to_page((void *)addr));
-       }
-
        return dmah;
 }
 
@@ -94,19 +85,9 @@ EXPORT_SYMBOL(drm_pci_alloc);
  */
 void __drm_legacy_pci_free(struct drm_device * dev, drm_dma_handle_t * dmah)
 {
-       unsigned long addr;
-       size_t sz;
-
-       if (dmah->vaddr) {
-               /* XXX - Is virt_to_page() legal for consistent mem? */
-               /* Unreserve */
-               for (addr = (unsigned long)dmah->vaddr, sz = dmah->size;
-                    sz > 0; addr += PAGE_SIZE, sz -= PAGE_SIZE) {
-                       ClearPageReserved(virt_to_page((void *)addr));
-               }
+       if (dmah->vaddr)
                dma_free_coherent(&dev->pdev->dev, dmah->size, dmah->vaddr,
                                  dmah->busaddr);
-       }
 }
 
 /**