[PATCH v2 15/21] xen-blkfront: Make use of the new sg_map helper function

Logan Gunthorpe
2017-04-25T18:21:02Z

Straightforward conversion to the new helper, except due to the lack
of error path, we have to use SG_MAP_MUST_NOT_FAIL which may BUG_ON in
certain cases in the future.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
---
drivers/block/xen-blkfront.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 3945963..ed62175 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -816,8 +816,9 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
BUG_ON(sg->offset + sg->length > PAGE_SIZE);

if (setup.need_copy) {
- setup.bvec_off = sg->offset;
- setup.bvec_data = kmap_atomic(sg_page(sg));
+ setup.bvec_off = 0;
+ setup.bvec_data = sg_map(sg, 0, SG_KMAP_ATOMIC |
+ SG_MAP_MUST_NOT_FAIL);
}

gnttab_foreach_grant_in_range(sg_page(sg),
@@ -827,7 +828,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
&setup);

if (setup.need_copy)
- kunmap_atomic(setup.bvec_data);
+ sg_unmap(sg, setup.bvec_data, 0, SG_KMAP_ATOMIC);
}
if (setup.segments)
kunmap_atomic(setup.segments);
@@ -1053,7 +1054,7 @@ static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
case XEN_SCSI_DISK5_MAJOR:
case XEN_SCSI_DISK6_MAJOR:
case XEN_SCSI_DISK7_MAJOR:
- *offset = (*minor / PARTS_PER_DISK) +
+ *offset = (*minor / PARTS_PER_DISK) +
((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
EMULATED_SD_DISK_NAME_OFFSET;
*minor = *minor +
@@ -1068,7 +1069,7 @@ static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
case XEN_SCSI_DISK13_MAJOR:
case XEN_SCSI_DISK14_MAJOR:
case XEN_SCSI_DISK15_MAJOR:
- *offset = (*minor / PARTS_PER_DISK) +
+ *offset = (*minor / PARTS_PER_DISK) +
((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
EMULATED_SD_DISK_NAME_OFFSET;
*minor = *minor +
@@ -1119,7 +1120,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
if (!VDEV_IS_EXTENDED(info->vdevice)) {
err = xen_translate_vdev(info->vdevice, &minor, &offset);
if (err)
- return err;
+ return err;
nr_parts = PARTS_PER_DISK;
} else {
minor = BLKIF_MINOR_EXT(info->vdevice);
@@ -1483,8 +1484,9 @@ static bool blkif_completion(unsigned long *id,
for_each_sg(s->sg, sg, num_sg, i) {
BUG_ON(sg->offset + sg->length > PAGE_SIZE);

- data.bvec_offset = sg->offset;
- data.bvec_data = kmap_atomic(sg_page(sg));
+ data.bvec_offset = 0;
+ data.bvec_data = sg_map(sg, 0, SG_KMAP_ATOMIC |
+ SG_MAP_MUST_NOT_FAIL);

gnttab_foreach_grant_in_range(sg_page(sg),
sg->offset,
@@ -1492,7 +1494,7 @@ static bool blkif_completion(unsigned long *id,
blkif_copy_from_grant,
&data);

- kunmap_atomic(data.bvec_data);
+ sg_unmap(sg, data.bvec_data, 0, SG_KMAP_ATOMIC);
}
}
/* Add the persistent grant into the list of free grants */
--
2.1.4

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