Commit 46348456 authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Jens Axboe
Browse files

block: Copy a user iovec if it includes gaps 



For drivers that don't support gaps in the SG lists handed to
them we must bounce (copy the user buffers) and pass a bio that
does not include gaps. This doesn't matter for any current user,
but will help to allow iser which can't handle gaps to use the
block virtual boundary instead of using driver-local bounce
buffering when handling SG_IO commands.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSagi Grimberg <sagig@mellanox.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 87a816df

block/blk-map.c

+24 −2
Original line number Diff line number Diff line
@@ -9,6 +9,24 @@ 


#include "blk.h"



static bool iovec_gap_to_prv(struct request_queue *q,

			     struct iovec *prv, struct iovec *cur)

{

	unsigned long prev_end;



	if (!queue_virt_boundary(q))

		return false;



	if (prv->iov_base == NULL && prv->iov_len == 0)

		/* prv is not set - don't check */

		return false;



	prev_end = (unsigned long)(prv->iov_base + prv->iov_len);



	return (((unsigned long)cur->iov_base & queue_virt_boundary(q)) ||

		prev_end & queue_virt_boundary(q));

}



int blk_rq_append_bio(struct request_queue *q, struct request *rq,

		      struct bio *bio)

{
@@ -67,7 +85,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, 
	struct bio *bio;

	int unaligned = 0;

	struct iov_iter i;

	struct iovec iov;

	struct iovec iov, prv = {.iov_base = NULL, .iov_len = 0};



	if (!iter || !iter->count)

		return -EINVAL;
@@ -81,8 +99,12 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, 
		/*

		 * Keep going so we check length of all segments

		 */

		if (uaddr & queue_dma_alignment(q))

		if ((uaddr & queue_dma_alignment(q)) ||

		    iovec_gap_to_prv(q, &prv, &iov))

			unaligned = 1;



		prv.iov_base = iov.iov_base;

		prv.iov_len = iov.iov_len;

	}



	if (unaligned || (q->dma_pad_mask & iter->count) || map_data)

CRA Git | Maintained and supported by SUSTech CRA and CCSE