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From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org,
	linux-media@vger.kernel.org, chris@chris-wilson.co.uk,
	airlied@redhat.com, akpm@linux-foundation.org, daniel@ffwll.ch,
	sumit.semwal@linaro.org
Subject: [PATCH 2/4] drm/prime: document that use the page array is deprecated
Date: Thu,  8 Oct 2020 13:23:40 +0200	[thread overview]
Message-ID: <20201008112342.9394-2-christian.koenig@amd.com> (raw)
In-Reply-To: <20201008112342.9394-1-christian.koenig@amd.com>

We have reoccurring requests on this so better document that
this approach doesn't work and dma_buf_mmap() needs to be used instead.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/drm_prime.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 4910c446db83..16fa2bfc271e 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -956,7 +956,7 @@ EXPORT_SYMBOL(drm_gem_prime_import);
 /**
  * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
  * @sgt: scatter-gather table to convert
- * @pages: optional array of page pointers to store the page array in
+ * @pages: deprecated array of page pointers to store the page array in
  * @addrs: optional array to store the dma bus address of each page
  * @max_entries: size of both the passed-in arrays
  *
@@ -965,6 +965,11 @@ EXPORT_SYMBOL(drm_gem_prime_import);
  *
  * Drivers can use this in their &drm_driver.gem_prime_import_sg_table
  * implementation.
+ *
+ * Specifying the pages array is deprecated and strongly discouraged for new
+ * drivers. The pages array is only useful for page faults and those can
+ * corrupt fields in the struct page if they are not handled by the exporting
+ * driver.
  */
 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 				     dma_addr_t *addrs, int max_entries)
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org,
	linux-media@vger.kernel.org, chris@chris-wilson.co.uk,
	airlied@redhat.com, akpm@linux-foundation.org, daniel@ffwll.ch,
	sumit.semwal@linaro.org
Subject: [PATCH 2/4] drm/prime: document that use the page array is deprecated
Date: Thu,  8 Oct 2020 13:23:40 +0200	[thread overview]
Message-ID: <20201008112342.9394-2-christian.koenig@amd.com> (raw)
In-Reply-To: <20201008112342.9394-1-christian.koenig@amd.com>

We have reoccurring requests on this so better document that
this approach doesn't work and dma_buf_mmap() needs to be used instead.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/drm_prime.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 4910c446db83..16fa2bfc271e 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -956,7 +956,7 @@ EXPORT_SYMBOL(drm_gem_prime_import);
 /**
  * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
  * @sgt: scatter-gather table to convert
- * @pages: optional array of page pointers to store the page array in
+ * @pages: deprecated array of page pointers to store the page array in
  * @addrs: optional array to store the dma bus address of each page
  * @max_entries: size of both the passed-in arrays
  *
@@ -965,6 +965,11 @@ EXPORT_SYMBOL(drm_gem_prime_import);
  *
  * Drivers can use this in their &drm_driver.gem_prime_import_sg_table
  * implementation.
+ *
+ * Specifying the pages array is deprecated and strongly discouraged for new
+ * drivers. The pages array is only useful for page faults and those can
+ * corrupt fields in the struct page if they are not handled by the exporting
+ * driver.
  */
 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 				     dma_addr_t *addrs, int max_entries)
-- 
2.17.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  reply	other threads:[~2020-10-08 11:23 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-08 11:23 [PATCH 1/4] mm: introduce vma_set_file function v2 Christian König
2020-10-08 11:23 ` Christian König
2020-10-08 11:23 ` Christian König [this message]
2020-10-08 11:23   ` [PATCH 2/4] drm/prime: document that use the page array is deprecated Christian König
2020-10-08 14:09   ` Daniel Vetter
2020-10-08 14:09     ` Daniel Vetter
2020-10-08 14:14     ` Daniel Vetter
2020-10-08 14:14       ` Daniel Vetter
2020-10-09  7:36       ` Christian König
2020-10-09  7:36         ` Christian König
2020-10-09  7:40         ` Daniel Vetter
2020-10-09  7:40           ` Daniel Vetter
2020-10-08 11:23 ` [PATCH 3/4] drm/radeon: stop using pages with drm_prime_sg_to_page_addr_arrays Christian König
2020-10-08 11:23   ` Christian König
2020-10-08 11:23 ` [PATCH 4/4] drm/amdgpu: " Christian König
2020-10-08 11:23   ` Christian König
2020-10-08 11:39 ` [PATCH 1/4] mm: introduce vma_set_file function v2 Matthew Wilcox
2020-10-08 11:39   ` Matthew Wilcox
2020-10-08 12:06   ` Christian König
2020-10-08 12:06     ` Christian König
2020-10-08 14:12 ` Daniel Vetter
2020-10-08 14:12   ` Daniel Vetter
2020-10-09  7:16   ` Christian König
2020-10-09  7:16     ` Christian König
2020-10-09  7:39     ` Daniel Vetter
2020-10-09  7:39       ` Daniel Vetter
2020-10-09 12:12       ` Jason Gunthorpe
2020-10-09 12:12         ` Jason Gunthorpe
2020-10-09 12:15         ` Christian König
2020-10-09 12:15           ` Christian König
2020-10-08 15:35 ` kernel test robot
2020-10-08 15:35   ` kernel test robot
2020-10-08 15:35   ` kernel test robot
2020-10-08 16:19 ` kernel test robot
2020-10-08 16:19   ` kernel test robot
2020-10-08 16:19   ` kernel test robot
2020-10-08 21:49 ` John Hubbard
2020-10-08 21:49   ` John Hubbard
2020-10-09  7:33   ` Christian König
2020-10-09  7:33     ` Christian König
2020-10-09  7:36     ` John Hubbard
2020-10-09  7:36       ` John Hubbard

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