From 0a2b3e363566c4cc8792d37c5e73b9d9295e075c Mon Sep 17 00:00:00 2001 From: Coly Li Date: Wed, 20 Oct 2021 22:38:06 +0800 Subject: [PATCH] bcache: reserve never used bits from bkey.high There sre 3 bits in member high of struct bkey are never used, and no plan to support them in future, - HEADER_SIZE, start at bit 58, length 2 bits - KEY_PINNED, start at bit 55, length 1 bit No any kernel code, or user space tool references or accesses the three bits. Therefore it is possible and feasible to reserve the valuable bits from bkey.high. They can be used in future for other purpose. Signed-off-by: Coly Li Link: https://lore.kernel.org/r/20211020143812.6403-3-colyli@suse.de Signed-off-by: Jens Axboe --- include/uapi/linux/bcache.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h index cf7399f03b71..97413586195b 100644 --- a/include/uapi/linux/bcache.h +++ b/include/uapi/linux/bcache.h @@ -43,9 +43,9 @@ static inline void SET_##name(struct bkey *k, unsigned int i, __u64 v) \ #define KEY_MAX_U64S 8 KEY_FIELD(KEY_PTRS, high, 60, 3) -KEY_FIELD(HEADER_SIZE, high, 58, 2) +KEY_FIELD(__PAD0, high, 58, 2) KEY_FIELD(KEY_CSUM, high, 56, 2) -KEY_FIELD(KEY_PINNED, high, 55, 1) +KEY_FIELD(__PAD1, high, 55, 1) KEY_FIELD(KEY_DIRTY, high, 36, 1) KEY_FIELD(KEY_SIZE, high, 20, KEY_SIZE_BITS) -- 2.39.5