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authorLinus Torvalds <torvalds@linux-foundation.org>2016-05-22 14:19:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-22 14:19:37 -0700
commit5b09c3edecd37ec1a52fbd5ae97a19734edc7a77 (patch)
tree899fbf0a4255f76ae18d280b216b8ddede02512b
parentf6c658df63856db3bf8f467024b1dbee37b5399c (diff)
x86: remove pointless uaccess_32.h complexity
I'm looking at trying to possibly merge the 32-bit and 64-bit versions of the x86 uaccess.h implementation, but first this needs to be cleaned up. For example, the 32-bit version of "__copy_to_user_inatomic()" is mostly the special cases for the constant size, and it's actually never relevant. Every user except for one aren't actually using a constant size anyway, and the one user that uses it is better off just using __put_user() instead. So get rid of the unnecessary complexity. [ The same cleanup should likely happen to __copy_from_user_inatomic() as well, but that one has a lot more users that I need to take a look at first ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/x86/include/asm/uaccess_32.h36
-rw-r--r--drivers/gpu/drm/i915/i915_gem_execbuffer.c4
2 files changed, 1 insertions, 39 deletions
diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index 3fe0eac59462..537cc883ea29 100644
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -33,46 +33,10 @@ unsigned long __must_check __copy_from_user_ll_nocache_nozero
* the specified block with access_ok() before calling this function.
* The caller should also make sure he pins the user space address
* so that we don't result in page fault and sleep.
- *
- * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
- * we return the initial request size (1, 2 or 4), as copy_*_user should do.
- * If a store crosses a page boundary and gets a fault, the x86 will not write
- * anything, so this is accurate.
*/
-
static __always_inline unsigned long __must_check
__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
{
- if (__builtin_constant_p(n)) {
- unsigned long ret;
-
- switch (n) {
- case 1:
- __uaccess_begin();
- __put_user_size(*(u8 *)from, (u8 __user *)to,
- 1, ret, 1);
- __uaccess_end();
- return ret;
- case 2:
- __uaccess_begin();
- __put_user_size(*(u16 *)from, (u16 __user *)to,
- 2, ret, 2);
- __uaccess_end();
- return ret;
- case 4:
- __uaccess_begin();
- __put_user_size(*(u32 *)from, (u32 __user *)to,
- 4, ret, 4);
- __uaccess_end();
- return ret;
- case 8:
- __uaccess_begin();
- __put_user_size(*(u64 *)from, (u64 __user *)to,
- 8, ret, 8);
- __uaccess_end();
- return ret;
- }
- }
return __copy_to_user_ll(to, from, n);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index a676eedb441b..d4d7c88ab595 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -535,9 +535,7 @@ i915_gem_execbuffer_relocate_vma(struct i915_vma *vma,
return ret;
if (r->presumed_offset != offset &&
- __copy_to_user_inatomic(&user_relocs->presumed_offset,
- &r->presumed_offset,
- sizeof(r->presumed_offset))) {
+ __put_user(r->presumed_offset, &user_relocs->presumed_offset)) {
return -EFAULT;
}