mm/memory.c: avoid unnecessary kernel/user pointer conversion

Annotating a pointer from __user to kernel and then back again might
confuse sparse.  In copy_huge_page_from_user() it can be avoided by
removing the intermediate variable since it is never used.

Link: https://lkml.kernel.org/r/20210914150820.19326-1-amit.kachhap@arm.com
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: amitdanielkachhap

mm/memory.c

@@ -5421,7 +5421,6 @@ long copy_huge_page_from_user(struct page *dst_page,
 				unsigned int pages_per_huge_page,
 				bool allow_pagefault)
 {
-	void *src = (void *)usr_src;
 	void *page_kaddr;
 	unsigned long i, rc = 0;
 	unsigned long ret_val = pages_per_huge_page * PAGE_SIZE;
@@ -5434,8 +5433,7 @@ long copy_huge_page_from_user(struct page *dst_page,
 		else
 			page_kaddr = kmap_atomic(subpage);
 		rc = copy_from_user(page_kaddr,
-				(const void __user *)(src + i * PAGE_SIZE),
-				PAGE_SIZE);
+				usr_src + i * PAGE_SIZE, PAGE_SIZE);
 		if (allow_pagefault)
 			kunmap(subpage);
 		else