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Date: Tue, 25 Aug 2020 14:52:47 +0000 From: David Laight <David.Laight@...LAB.COM> To: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "'linux-sctp@...r.kernel.org'" <linux-sctp@...r.kernel.org>, Eric Biggers <ebiggers@...nel.org>, 'Marcelo Ricardo Leitner' <marcelo.leitner@...il.com>, 'Catalin Marinas' <catalin.marinas@....com>, "'kent.overstreet@...il.com'" <kent.overstreet@...il.com>, Andrew Morton <akpm@...ux-foundation.org>, "'Neil Horman'" <nhorman@...driver.com> Subject: [PATCH 10/13] lib/generic-radix-tree: Simplify offset calculation: 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 <david.laight@...lab.com> --- 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)
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