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
next prev parent reply other threads:[~2020-10-08 11:23 UTC|newest]
Thread overview: 20+ 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 [this message]
2020-10-08 14:09 ` [PATCH 2/4] drm/prime: document that use the page array is deprecated Daniel Vetter
2020-10-08 14:14 ` Daniel Vetter
2020-10-09 7:36 ` Christian König
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 ` [PATCH 4/4] drm/amdgpu: " Christian König
2020-10-08 11:39 ` [PATCH 1/4] mm: introduce vma_set_file function v2 Matthew Wilcox
2020-10-08 12:06 ` Christian König
2020-10-08 14:12 ` Daniel Vetter
2020-10-09 7:16 ` Christian König
2020-10-09 7:39 ` Daniel Vetter
2020-10-09 12:12 ` Jason Gunthorpe
2020-10-09 12:15 ` Christian König
2020-10-08 15:35 ` kernel test robot
2020-10-08 16:19 ` kernel test robot
2020-10-08 21:49 ` John Hubbard
2020-10-09 7:33 ` Christian König
2020-10-09 7:36 ` John Hubbard
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