This function is used to proceed page iterator to the next page if
necessary, and will be used to implement the variants of
sg_copy_{from,to}_buffer() later.Signed-off-by: Akinobu Mita <[email protected]> Acked-by: Tejun Heo <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Imre Deak <[email protected]> Cc: Herbert Xu <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: [email protected] Cc: "James E.J. Bottomley" <[email protected]> Cc: Douglas Gilbert <[email protected]> Cc: [email protected] --- * Change from v2 - Add Acked-by line lib/scatterlist.c | 39 ++++++++++++++++++++++++--------------- 1 file changed, 24 insertions(+), 15 deletions(-) diff --git a/lib/scatterlist.c b/lib/scatterlist.c index a1cf8ca..c35b929 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -453,6 +453,28 @@ void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, } EXPORT_SYMBOL(sg_miter_start); +static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) +{ + if (!miter->__remaining) { + struct scatterlist *sg; + unsigned long pgoffset; + + if (!__sg_page_iter_next(&miter->piter)) + return false; + + sg = miter->piter.sg; + pgoffset = miter->piter.sg_pgoffset; + + miter->__offset = pgoffset ? 0 : sg->offset; + miter->__remaining = sg->offset + sg->length - + (pgoffset << PAGE_SHIFT) - miter->__offset; + miter->__remaining = min_t(unsigned long, miter->__remaining, + PAGE_SIZE - miter->__offset); + } + + return true; +} + /** * sg_miter_next - proceed mapping iterator to the next mapping * @miter: sg mapping iter to proceed @@ -478,22 +500,9 @@ bool sg_miter_next(struct sg_mapping_iter *miter) * Get to the next page if necessary. * __remaining, __offset is adjusted by sg_miter_stop */ - if (!miter->__remaining) { - struct scatterlist *sg; - unsigned long pgoffset; - - if (!__sg_page_iter_next(&miter->piter)) - return false; - - sg = miter->piter.sg; - pgoffset = miter->piter.sg_pgoffset; + if (!sg_miter_get_next_page(miter)) + return false; - miter->__offset = pgoffset ? 0 : sg->offset; - miter->__remaining = sg->offset + sg->length - - (pgoffset << PAGE_SHIFT) - miter->__offset; - miter->__remaining = min_t(unsigned long, miter->__remaining, - PAGE_SIZE - miter->__offset); - } miter->page = sg_page_iter_page(&miter->piter); miter->consumed = miter->length = miter->__remaining; -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
