[PATCH RESEND] drm/i915/gem: Use user_write_access_begin() instead of user_access_begin()

From: Christophe Leroy
Date: Sat May 01 2021 - 04:20:23 EST


eb_copy_relocations() only do unsafe_put_user(), it only
requires write access to user.

Use user_write_access_begin() instead of user_access_begin().

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
Resending with mm list in addition

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 5964e67c7d36..f7a7bb45274b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1907,14 +1907,14 @@ static int eb_copy_relocations(const struct i915_execbuffer *eb)
* happened we would make the mistake of assuming that the
* relocations were valid.
*/
- if (!user_access_begin(urelocs, size))
+ if (!user_write_access_begin(urelocs, size))
goto end;

for (copied = 0; copied < nreloc; copied++)
unsafe_put_user(-1,
&urelocs[copied].presumed_offset,
end_user);
- user_access_end();
+ user_write_access_end();

eb->exec[i].relocs_ptr = (uintptr_t)relocs;
}
@@ -1922,7 +1922,7 @@ static int eb_copy_relocations(const struct i915_execbuffer *eb)
return 0;

end_user:
- user_access_end();
+ user_write_access_end();
end:
kvfree(relocs);
err = -EFAULT;
--
2.25.0