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-rw-r--r--debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch74
1 files changed, 74 insertions, 0 deletions
diff --git a/debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch b/debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch
new file mode 100644
index 000000000..3043aa642
--- /dev/null
+++ b/debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch
@@ -0,0 +1,74 @@
+From 818c332a89ac4310c59f7ad122bdb4a6e0aac518 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:43 +0100
+Subject: [PATCH 054/323] drm/ttm: Replace kmap_atomic() usage
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There is no reason to disable pagefaults and preemption as a side effect of
+kmap_atomic_prot().
+
+Use kmap_local_page_prot() instead and document the reasoning for the
+mapping usage with the given pgprot.
+
+Remove the NULL pointer check for the map. These functions return a valid
+address for valid pages and the return was bogus anyway as it would have
+left preemption and pagefaults disabled.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Christian Koenig <christian.koenig@amd.com>
+Cc: Huang Rui <ray.huang@amd.com>
+Cc: David Airlie <airlied@linux.ie>
+Cc: Daniel Vetter <daniel@ffwll.ch>
+Cc: dri-devel@lists.freedesktop.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/ttm/ttm_bo_util.c | 20 ++++++++++++--------
+ 1 file changed, 12 insertions(+), 8 deletions(-)
+
+diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
+index 1968df9743fc..79b9c883431a 100644
+--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
++++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
+@@ -181,13 +181,15 @@ static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
+ return -ENOMEM;
+
+ src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
+- dst = kmap_atomic_prot(d, prot);
+- if (!dst)
+- return -ENOMEM;
++ /*
++ * Ensure that a highmem page is mapped with the correct
++ * pgprot. For non highmem the mapping is already there.
++ */
++ dst = kmap_local_page_prot(d, prot);
+
+ memcpy_fromio(dst, src, PAGE_SIZE);
+
+- kunmap_atomic(dst);
++ kunmap_local(dst);
+
+ return 0;
+ }
+@@ -203,13 +205,15 @@ static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
+ return -ENOMEM;
+
+ dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
+- src = kmap_atomic_prot(s, prot);
+- if (!src)
+- return -ENOMEM;
++ /*
++ * Ensure that a highmem page is mapped with the correct
++ * pgprot. For non highmem the mapping is already there.
++ */
++ src = kmap_local_page_prot(s, prot);
+
+ memcpy_toio(dst, src, PAGE_SIZE);
+
+- kunmap_atomic(src);
++ kunmap_local(src);
+
+ return 0;
+ }
+--
+2.43.0
+