On 12/3/20 3:29 AM, Ming Lei wrote:
Pavel reported that iov_iter_npages is a bit heavy in case of bvec iter. Turns out it isn't necessary to iterate every page in the bvec iter, and we call iov_iter_npages() just for figuring out how many bio vecs need to be allocated. And we can simply map each vector in bvec iter to bio's vec, so just return iter->nr_segs from bio_iov_iter_nvecs() for bvec iter. This patch is based on Mathew's post: https://lore.kernel.org/linux-block/20201120123931.GN29991@xxxxxxxxxxxxxxxxxxxx/ Reviewed-by: Pavel Begunkov <asml.silence@xxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: linux-fsdevel@xxxxxxxxxxxxxxx Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- fs/block_dev.c | 4 ++-- fs/iomap/direct-io.c | 4 ++-- include/linux/bio.h | 10 ++++++++++ 3 files changed, 14 insertions(+), 4 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@xxxxxxx +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
