From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Tue, 25 Aug 2020 14:52:47 +0000 Subject: [PATCH 10/13] lib/generic-radix-tree: Simplify offset calculation: Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "linux-kernel@vger.kernel.org" , "'linux-sctp@vger.kernel.org'" , Eric Biggers , 'Marcelo Ricardo Leitner' , 'Catalin Marinas' , "'kent.overstreet@gmail.com'" , Andrew Morton , 'Neil Horman' Since these are equivalent: (idx / objs_per_page) * PAGE_SIZE + (idx % objs_per_page) * obj_size; idx * obj_size + (idx / objs_per_page) * (PAGE_SIZE % obj_size); Use the latter since it is slightly faster. It also deosn't need an extra check for obj_size being a power of 2. Signed-off-by: David Laight --- include/linux/generic-radix-tree.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/include/linux/generic-radix-tree.h b/include/linux/generic-radix-tree.h index 53149bc1b92a..5fe1c4c5588d 100644 --- a/include/linux/generic-radix-tree.h +++ b/include/linux/generic-radix-tree.h @@ -100,14 +100,9 @@ void __genradix_free(struct __genradix *); static inline size_t __idx_to_offset(size_t idx, size_t obj_size) { - if (!is_power_of_2(obj_size)) { - size_t objs_per_page = PAGE_SIZE / obj_size; + size_t objs_per_page = PAGE_SIZE / obj_size; - return (idx / objs_per_page) * PAGE_SIZE + - (idx % objs_per_page) * obj_size; - } else { - return idx * obj_size; - } + return idx * obj_size + (idx / objs_per_page) * (PAGE_SIZE % obj_size); } #define __genradix_cast(_radix) (typeof((_radix)->type[0]) *) -- 2.25.1 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)