[PATCH RESEND 3/4] drm/i915/gem: Replace user_access_begin by user_write_access_begin

[Christophe Leroy]

When i915_gem_execbuffer2_ioctl() is using user_access_begin(),
that's only to perform unsafe_put_user() so use
user_write_access_begin() in order to only open write access.

Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c 
b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 7643a30ba4cd..4be8205a70b6 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1611,14 +1611,14 @@ 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;
        }
@@ -1626,7 +1626,7 @@ 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;
@@ -2991,7 +2991,8 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void 
*data,
                 * And this range already got effectively checked earlier
                 * when we did the "copy_from_user()" above.
                 */
-               if (!user_access_begin(user_exec_list, count * 
sizeof(*user_exec_list)))
+               if (!user_write_access_begin(user_exec_list,
+                                            count * sizeof(*user_exec_list)))
                        goto end;
 
                for (i = 0; i < args->buffer_count; i++) {
@@ -3005,7 +3006,7 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void 
*data,
                                        end_user);
                }
 end_user:
-               user_access_end();
+               user_write_access_end();
 end:;
        }
 
-- 
2.25.0