linux-kernel - [PATCH 5.6 203/254] drm: Remove PageReserved manipulation from drm_pci

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Message-Id: <20200416131351.475665135@linuxfoundation.org>
Date:   Thu, 16 Apr 2020 15:24:52 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chris Wilson <chris@...is-wilson.co.uk>,
        Alex Deucher <alexander.deucher@....com>
Subject: [PATCH 5.6 203/254] drm: Remove PageReserved manipulation from drm_pci_alloc

From: Chris Wilson <chris@...is-wilson.co.uk>

commit ea36ec8623f56791c6ff6738d0509b7920f85220 upstream.

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@...ux.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@...is-wilson.co.uk>
Cc: <stable@...r.kernel.org> # v4.5+
Reviewed-by: Alex Deucher <alexander.deucher@....com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200202171635.4039044-1-chris@chris-wilson.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/drm_pci.c |   23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

--- 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 d
 	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);
-	}
 }
 
 /**