Re: [Intel-gfx] [PATCH] drm/i915: Skip remap_io_mapping() for non-x86 platforms

[Lucas De Marchi <lucas.demarchi@intel.com>]

On Mon, Nov 22, 2021 at 06:01:42PM +0530, Mullati Siva wrote:
>From: Siva Mullati <siva.mullati@intel.com>
>
>Only hw that supports mappable aperture would hit this path
>vm_fault_gtt/vm_fault_tmm, So we never hit this function
>remap_io_mapping() in discrete, So skip this code for non-x86
>architectures.
>
>Signed-off-by: Siva Mullati <siva.mullati@intel.com>
>---
> drivers/gpu/drm/i915/gem/i915_gem_mman.c |  1 +
> drivers/gpu/drm/i915/i915_drv.h          |  8 ------
> drivers/gpu/drm/i915/i915_mm.c           |  1 +
> drivers/gpu/drm/i915/i915_mm.h           | 32 ++++++++++++++++++++++++
> 4 files changed, 34 insertions(+), 8 deletions(-)
> create mode 100644 drivers/gpu/drm/i915/i915_mm.h
>
>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>index 65fc6ff5f59d..39bb15eafc07 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
>@@ -17,6 +17,7 @@
> #include "i915_gem_ioctls.h"
> #include "i915_gem_object.h"
> #include "i915_gem_mman.h"
>+#include "i915_mm.h"
> #include "i915_trace.h"
> #include "i915_user_extensions.h"
> #include "i915_gem_ttm.h"
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index 1bfadd9127fc..7ae0f0cc6866 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -1967,14 +1967,6 @@ mkwrite_device_info(struct drm_i915_private *dev_priv)
> int i915_reg_read_ioctl(struct drm_device *dev, void *data,
> 			struct drm_file *file);
>
>-/* i915_mm.c */
>-int remap_io_mapping(struct vm_area_struct *vma,
>-		     unsigned long addr, unsigned long pfn, unsigned long size,
>-		     struct io_mapping *iomap);
>-int remap_io_sg(struct vm_area_struct *vma,
>-		unsigned long addr, unsigned long size,
>-		struct scatterlist *sgl, resource_size_t iobase);
>-
> static inline int intel_hws_csb_write_index(struct drm_i915_private *i915)
> {
> 	if (GRAPHICS_VER(i915) >= 11)
>diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
>index 666808cb3a32..f4df15fe7cf8 100644
>--- a/drivers/gpu/drm/i915/i915_mm.c
>+++ b/drivers/gpu/drm/i915/i915_mm.c
>@@ -27,6 +27,7 @@
>
>
> #include "i915_drv.h"
>+#include "i915_mm.h"
>
> struct remap_pfn {
> 	struct mm_struct *mm;
>diff --git a/drivers/gpu/drm/i915/i915_mm.h b/drivers/gpu/drm/i915/i915_mm.h
>new file mode 100644
>index 000000000000..1d3bbb9cbf43
>--- /dev/null
>+++ b/drivers/gpu/drm/i915/i915_mm.h
>@@ -0,0 +1,32 @@
>+/* SPDX-License-Identifier: MIT */
>+/*
>+ * Copyright © 2021 Intel Corporation
>+ */
>+
>+#ifndef __I915_MM_H__
>+#define __I915_MM_H__
>+
>+#include <linux/types.h>
>+
>+struct vm_area_struct;
>+struct io_mapping;
>+struct scatterlist;
>+
>+#if IS_ENABLED(CONFIG_X86)
>+int remap_io_mapping(struct vm_area_struct *vma,
>+		unsigned long addr, unsigned long pfn, unsigned long size,
>+		struct io_mapping *iomap);
>+#else
>+static inline int remap_io_mapping(struct vm_area_struct *vma,
>+		unsigned long addr, unsigned long pfn, unsigned long size,
>+		struct io_mapping *iomap)
>+{

would probably be good to add:

	pr_err("Architecture has no remap_io_mapping() and shouldn't be calling this function\n");
	WARN_ON_ONCE(1);

the same way that is done in drivers/gpu/drm/drm_cache.c

Other than that:


Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>

Since you're adding this header, can you follow up with one additional
patch to move the rest of the prototypes off i915_drv.h and into this
new header?


thanks
Lucas De Marchi


>+	return 0;
>+}
>+#endif
>+
>+int remap_io_sg(struct vm_area_struct *vma,
>+		unsigned long addr, unsigned long size,
>+		struct scatterlist *sgl, resource_size_t iobase);
>+
>+#endif /* __I915_MM_H__ */
>-- 
>2.33.0
>