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Commit 56c451f4 authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by James Bottomley
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[SCSI] block: fix the partial mappings with struct rq_map_data 



This fixes bio_copy_user_iov to properly handle the partial mappings
with struct rq_map_data (which only sg uses for now but st and osst
will shortly). It adds the offset member to struct rq_map_data and
changes blk_rq_map_user to update it so that bio_copy_user_iov can add
an appropriate page frame via bio_add_pc_page().

Signed-off-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: default avatarJens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent e623ddb4

block/blk-map.c

+3 −0
Original line number Diff line number Diff line
@@ -150,6 +150,9 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq, 
			bio = rq->bio;

		bytes_read += ret;

		ubuf += ret;



		if (map_data)

			map_data->offset += ret;

	}



	if (!bio_flagged(bio, BIO_USER_MAPPED))

drivers/scsi/sg.c

+1 −0
Original line number Diff line number Diff line
@@ -1669,6 +1669,7 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd) 
		md->pages = req_schp->pages;

		md->page_order = req_schp->page_order;

		md->nr_entries = req_schp->k_use_sg;

		md->offset = 0;

	}



	if (iov_count)

fs/bio.c

+9 −3
Original line number Diff line number Diff line
@@ -788,6 +788,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
	int i, ret;

	int nr_pages = 0;

	unsigned int len = 0;

	unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;



	for (i = 0; i < iov_count; i++) {

		unsigned long uaddr;
@@ -814,12 +815,16 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
	bio->bi_rw |= (!write_to_vm << BIO_RW);



	ret = 0;

	i = 0;

	if (map_data)



	if (map_data) {

		nr_pages = 1 << map_data->page_order;

		i = map_data->offset / PAGE_SIZE;

	}

	while (len) {

		unsigned int bytes = PAGE_SIZE;



		bytes -= offset;



		if (bytes > len)

			bytes = len;
@@ -841,10 +846,11 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
			}

		}



		if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)

		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)

			break;



		len -= bytes;

		offset = 0;

	}



	if (ret)

include/linux/blkdev.h

+1 −0
Original line number Diff line number Diff line
@@ -690,6 +690,7 @@ struct rq_map_data { 
	struct page **pages;

	int page_order;

	int nr_entries;

	unsigned long offset;

};



struct req_iterator {