linux-kernel - [PATCH 05/16] drm: don't mark pages returned from drm_pci

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Message-Id: <20190614134726.3827-6-hch@lst.de>
Date:   Fri, 14 Jun 2019 15:47:15 +0200
From:   Christoph Hellwig <hch@....de>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Ian Abbott <abbotti@....co.uk>,
        H Hartley Sweeten <hsweeten@...ionengravers.com>
Cc:     Intel Linux Wireless <linuxwifi@...el.com>,
        linux-arm-kernel@...ts.infradead.org (moderated list:ARM PORT),
        dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        linux-rdma@...r.kernel.org, linux-media@...r.kernel.org,
        netdev@...r.kernel.org, linux-wireless@...r.kernel.org,
        linux-s390@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-mm@...ck.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 05/16] drm: don't mark pages returned from drm_pci_alloc reserved

We are not allowed to call virt_to_page on pages returned from
dma_alloc_coherent, as in many cases the virtual address returned
is aactually a kernel direct mapping.  Also there generally is no
need to mark dma memory as reserved.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 drivers/gpu/drm/drm_bufs.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 7418872d87c6..b640437ce90f 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -77,13 +77,6 @@ drm_dma_handle_t *drm_pci_alloc(struct drm_device * dev, size_t size, size_t ali
 		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;
 }
 
@@ -97,16 +90,9 @@ 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);
-	}
 }
 
 /**
-- 
2.20.1