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: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
---
block/blk-map.c | 3 +++
drivers/scsi/sg.c | 1 +
fs/bio.c | 12 +++++++++---
include/linux/blkdev.h | 1 +
4 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/block/blk-map.c b/block/blk-map.c
index 0f4b4b8..bc0ca0d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -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))
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 5103855..7d0b3d9 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -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)
diff --git a/fs/bio.c b/fs/bio.c
index 5fd6e98..879d4ef 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -635,6 +635,7 @@ 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;
@@ -661,12 +662,16 @@ 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;
@@ -688,10 +693,11 @@ 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)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a135256..3cef38f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -680,6 +680,7 @@ struct rq_map_data {
struct page **pages;
int page_order;
int nr_entries;
+ unsigned long offset;
};
struct req_iterator {
--
1.5.6.5
--
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