From 2e484610296b25f0a04b516bc144a00731d1d845 Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Thu, 27 Sep 2012 12:45:28 +0200 Subject: scatterlist: add sg_nents Useful helper to know the number of entries in scatterlist. Signed-off-by: Maxim Levitsky Cc: Alex Dubov Acked-by: Tejun Heo Cc: Jens Axboe Signed-off-by: Jens Axboe --- include/linux/scatterlist.h | 1 + lib/scatterlist.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 7b600da9a635..4bd6c06eb28e 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -201,6 +201,7 @@ static inline void *sg_virt(struct scatterlist *sg) return page_address(sg_page(sg)) + sg->offset; } +int sg_nents(struct scatterlist *sg); struct scatterlist *sg_next(struct scatterlist *); struct scatterlist *sg_last(struct scatterlist *s, unsigned int); void sg_init_table(struct scatterlist *, unsigned int); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index fadae774a20c..1bf60efb5e02 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -38,6 +38,28 @@ struct scatterlist *sg_next(struct scatterlist *sg) } EXPORT_SYMBOL(sg_next); +/** + * sg_nents - return total count of entries in scatterlist + * @sg: The scatterlist + * + * Description: + * Allows to know how many entries are in sg, taking into acount + * chaining as well + * + **/ +int sg_nents(struct scatterlist *sg) +{ + int nents = 0; + while (sg) { + nents++; + sg = sg_next(sg); + } + + return nents; +} +EXPORT_SYMBOL(sg_nents); + + /** * sg_last - return the last scatterlist entry in a list * @sgl: First entry in the scatterlist -- cgit v1.2.3