From c8164d8931fdee9ac5314708c4071adf1d997425 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 20 Mar 2013 15:37:08 +1030 Subject: [PATCH] scatterlist: introduce sg_unmark_end This is useful in places that recycle the same scatterlist multiple times, and do not want to incur the cost of sg_init_table every time in hot paths. Acked-by: Jens Axboe Signed-off-by: Paolo Bonzini Signed-off-by: Rusty Russell --- block/blk-integrity.c | 2 +- block/blk-merge.c | 2 +- include/linux/scatterlist.h | 16 ++++++++++++++++ 3 files changed, 18 insertions(+), 2 deletions(-) diff --git a/block/blk-integrity.c b/block/blk-integrity.c index dabd221857e1..03cf7179e8ef 100644 --- a/block/blk-integrity.c +++ b/block/blk-integrity.c @@ -110,7 +110,7 @@ new_segment: if (!sg) sg = sglist; else { - sg->page_link &= ~0x02; + sg_unmark_end(sg); sg = sg_next(sg); } diff --git a/block/blk-merge.c b/block/blk-merge.c index 936a110de0b9..5f2448253797 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -143,7 +143,7 @@ new_segment: * termination bit to avoid doing a full * sg_init_table() in drivers for each command. */ - (*sg)->page_link &= ~0x02; + sg_unmark_end(*sg); *sg = sg_next(*sg); } diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 2d8bdaef9611..bfc47e0de81c 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -171,6 +171,22 @@ static inline void sg_mark_end(struct scatterlist *sg) sg->page_link &= ~0x01; } +/** + * sg_unmark_end - Undo setting the end of the scatterlist + * @sg: SG entryScatterlist + * + * Description: + * Removes the termination marker from the given entry of the scatterlist. + * + **/ +static inline void sg_unmark_end(struct scatterlist *sg) +{ +#ifdef CONFIG_DEBUG_SG + BUG_ON(sg->sg_magic != SG_MAGIC); +#endif + sg->page_link &= ~0x02; +} + /** * sg_phys - Return physical address of an sg entry * @sg: SG entry