crypto: skcipher - remove redundant clamping to page size

In the case where skcipher_walk_next() allocates a bounce page, that
page by definition has size PAGE_SIZE.  The number of bytes to copy 'n'
is guaranteed to fit in it, since earlier in the function it was clamped
to be at most a page.  Therefore remove the unnecessary logic that tried
to clamp 'n' again to fit in the bounce page.

Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

Author: ebiggers

crypto/skcipher.c

@@ -250,6 +250,7 @@ static int skcipher_walk_next(struct skcipher_walk *walk)
 slow_path:
 		return skcipher_next_slow(walk, bsize);
 	}
+	walk->nbytes = n;
 
 	if (unlikely((walk->in.offset | walk->out.offset) & walk->alignmask)) {
 		if (!walk->page) {
@@ -259,15 +260,10 @@ static int skcipher_walk_next(struct skcipher_walk *walk)
 			if (!walk->page)
 				goto slow_path;
 		}
-
-		walk->nbytes = min_t(unsigned, n,
-				     PAGE_SIZE - offset_in_page(walk->page));
 		walk->flags |= SKCIPHER_WALK_COPY;
 		return skcipher_next_copy(walk);
 	}
 
-	walk->nbytes = n;
-
 	return skcipher_next_fast(walk);
 }