Merge branch 'hch' (maccess patches from Christoph Hellwig)

Merge non-faulting memory access cleanups from Christoph Hellwig:
 "Andrew and I decided to drop the patches implementing your suggested
  rename of the probe_kernel_* and probe_user_* helpers from -mm as
  there were way to many conflicts.

  After -rc1 might be a good time for this as all the conflicts are
  resolved now"

This also adds a type safety checking patch on top of the renaming
series to make the subtle behavioral difference between 'get_user()' and
'get_kernel_nofault()' less potentially dangerous and surprising.

* emailed patches from Christoph Hellwig <hch@lst.de>:
  maccess: make get_kernel_nofault() check for minimal type compatibility
  maccess: rename probe_kernel_address to get_kernel_nofault
  maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault
  maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

1 files changed, 13 insertions, 10 deletions

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 7bcadca22100..0a76ddc07d59 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -301,13 +301,14 @@ copy_struct_from_user(void *dst, size_t ksize, const void __user *src,
 	return 0;
 }
 
-bool probe_kernel_read_allowed(const void *unsafe_src, size_t size);
+bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size);
 
-extern long probe_kernel_read(void *dst, const void *src, size_t size);
-extern long probe_user_read(void *dst, const void __user *src, size_t size);
+long copy_from_kernel_nofault(void *dst, const void *src, size_t size);
+long notrace copy_to_kernel_nofault(void *dst, const void *src, size_t size);
 
-extern long notrace probe_kernel_write(void *dst, const void *src, size_t size);
-extern long notrace probe_user_write(void __user *dst, const void *src, size_t size);
+long copy_from_user_nofault(void *dst, const void __user *src, size_t size);
+long notrace copy_to_user_nofault(void __user *dst, const void *src,
+		size_t size);
 
 long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr,
 		long count);
@@ -317,14 +318,16 @@ long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
 long strnlen_user_nofault(const void __user *unsafe_addr, long count);
 
 /**
- * probe_kernel_address(): safely attempt to read from a location
- * @addr: address to read from
- * @retval: read into this variable
+ * get_kernel_nofault(): safely attempt to read from a location
+ * @val: read into this variable
+ * @ptr: address to read from
  *
  * Returns 0 on success, or -EFAULT.
  */
-#define probe_kernel_address(addr, retval)		\
-	probe_kernel_read(&retval, addr, sizeof(retval))
+#define get_kernel_nofault(val, ptr) ({				\
+	const typeof(val) *__gk_ptr = (ptr);			\
+	copy_from_kernel_nofault(&(val), __gk_ptr, sizeof(val));\
+})
 
 #ifndef user_access_begin
 #define user_access_begin(ptr,len) access_ok(ptr, len)