linux-kernel - [PATCH 1/2] drm/i915/gem: stop using PAGE_KERNEL

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Date:   Thu, 21 Oct 2021 11:15:10 -0700
From:   Lucas De Marchi <lucas.demarchi@...el.com>
To:     intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        xen-devel@...ts.xenproject.org,
        Daniel Vetter <daniel.vetter@...ll.ch>
Subject: [PATCH 1/2] drm/i915/gem: stop using PAGE_KERNEL_IO

PAGE_KERNEL_IO is only defined for x86 and nowadays is the same as
PAGE_KERNEL. It was different for some time, OR'ing a `_PAGE_IOMAP` flag
in commit be43d72835ba ("x86: add _PAGE_IOMAP pte flag for IO
mappings").  This got removed in commit f955371ca9d3 ("x86: remove the
Xen-specific _PAGE_IOMAP PTE flag"), so today they are just the same.

This is the same that was done in commit ac96b5566926 ("io-mapping.h:
s/PAGE_KERNEL_IO/PAGE_KERNEL/").

There is a subsequent commit with
'Fixes: ac96b5566926 ("io-mapping.h: s/PAGE_KERNEL_IO/PAGE_KERNEL/")' -
but that is not relevant here since is it's actually fixing the different
names for pgprot_writecombine(), which we also don't have today since
all archs expose pgprot_writecombine(). Microblaze, mentioned in that
discussion, gained pgprot_writecombine() in
commit 97ccedd793ac ("microblaze: Provide pgprot_device/writecombine
macros for nommu").

So, just use PAGE_KERNEL, and just use pgprot_writecombine().

Signed-off-by: Lucas De Marchi <lucas.demarchi@...el.com>
Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211020090625.1037517-1-lucas.demarchi@intel.com
---
 drivers/gpu/drm/i915/gem/i915_gem_pages.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 8eb1c3a6fc9c..68fe1837ef54 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -289,7 +289,7 @@ static void *i915_gem_object_map_page(struct drm_i915_gem_object *obj,
 		pgprot = PAGE_KERNEL;
 		break;
 	case I915_MAP_WC:
-		pgprot = pgprot_writecombine(PAGE_KERNEL_IO);
+		pgprot = pgprot_writecombine(PAGE_KERNEL);
 		break;
 	}

@@ -333,7 +333,7 @@ static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj,
 	i = 0;
 	for_each_sgt_daddr(addr, iter, obj->mm.pages)
 		pfns[i++] = (iomap + addr) >> PAGE_SHIFT;
-	vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL_IO));
+	vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL));
 	if (pfns != stack)
 		kvfree(pfns);

-- 
2.33.1