[PATCH 12/20] ublk: implement integrity user copy

Caleb Sander Mateos
2025-12-17T05:35:14Z

From: Stanley Zhang <stazhang@purestorage.com>

Add a function ublk_copy_user_integrity() to copy integrity information
between a request and a user iov_iter. This mirrors the existing
ublk_copy_user_pages() but operates on request integrity data instead of
regular data. Check UBLKSRV_IO_INTEGRITY_FLAG in iocb->ki_pos in
ublk_user_copy() to choose between copying data or integrity data.

Signed-off-by: Stanley Zhang <stazhang@purestorage.com>
[csander: change offset units from data bytes to integrity data bytes,
test UBLKSRV_IO_INTEGRITY_FLAG after subtracting UBLKSRV_IO_BUF_OFFSET,
fix CONFIG_BLK_DEV_INTEGRITY=n build,
rebase on ublk user copy refactor]
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
drivers/block/ublk_drv.c | 43 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 7fa0a9f0bfae..042df4de9253 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -606,10 +606,15 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
{
return ((pos - UBLKSRV_IO_BUF_OFFSET) >> UBLK_TAG_OFF) &
UBLK_TAG_BITS_MASK;
}

+static inline bool ublk_pos_is_integrity(loff_t pos)
+{
+ return !!((pos - UBLKSRV_IO_BUF_OFFSET) & UBLKSRV_IO_INTEGRITY_FLAG);
+}
+
static void ublk_dev_param_basic_apply(struct ublk_device *ub)
{
const struct ublk_param_basic *p = &ub->params.basic;

if (p->attrs & UBLK_ATTR_READ_ONLY)
@@ -1034,10 +1039,31 @@ static size_t ublk_copy_user_pages(const struct request *req,
break;
}
return done;
}

+static size_t ublk_copy_user_integrity(const struct request *req,
+ unsigned offset, struct iov_iter *uiter, int dir)
+{
+ size_t done = 0;
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+ struct bio *bio = req->bio;
+ struct bvec_iter iter;
+ struct bio_vec iv;
+
+ if (!blk_integrity_rq(req))
+ return 0;
+
+ bio_for_each_integrity_vec(iv, bio, iter) {
+ if (!ublk_copy_user_bvec(iv, &offset, uiter, dir, &done))
+ break;
+ }
+#endif
+
+ return done;
+}
+
static inline bool ublk_need_map_req(const struct request *req)
{
return ublk_rq_has_data(req) && req_op(req) == REQ_OP_WRITE;
}

@@ -2616,10 +2642,12 @@ ublk_user_copy(struct kiocb *iocb, struct iov_iter *iter, int dir)
{
struct ublk_device *ub = iocb->ki_filp->private_data;
struct ublk_queue *ubq;
struct request *req;
struct ublk_io *io;
+ unsigned data_len;
+ bool is_integrity;
size_t buf_off;
u16 tag, q_id;
ssize_t ret;

if (!user_backed_iter(iter))
@@ -2629,10 +2657,11 @@ ublk_user_copy(struct kiocb *iocb, struct iov_iter *iter, int dir)
return -EACCES;

tag = ublk_pos_to_tag(iocb->ki_pos);
q_id = ublk_pos_to_hwq(iocb->ki_pos);
buf_off = ublk_pos_to_buf_off(iocb->ki_pos);
+ is_integrity = ublk_pos_is_integrity(iocb->ki_pos);

if (q_id >= ub->dev_info.nr_hw_queues)
return -EINVAL;

ubq = ublk_get_queue(ub, q_id);
@@ -2645,21 +2674,31 @@ ublk_user_copy(struct kiocb *iocb, struct iov_iter *iter, int dir)
io = &ubq->ios[tag];
req = __ublk_check_and_get_req(ub, q_id, tag, io);
if (!req)
return -EINVAL;

- if (buf_off > blk_rq_bytes(req)) {
+ if (is_integrity) {
+ struct blk_integrity *bi = &req->q->limits.integrity;
+
+ data_len = bio_integrity_bytes(bi, blk_rq_sectors(req));
+ } else {
+ data_len = blk_rq_bytes(req);
+ }
+ if (buf_off > data_len) {
ret = -EINVAL;
goto out;
}

if (!ublk_check_ubuf_dir(req, dir)) {
ret = -EACCES;
goto out;
}

- ret = ublk_copy_user_pages(req, buf_off, iter, dir);
+ if (is_integrity)
+ ret = ublk_copy_user_integrity(req, buf_off, iter, dir);
+ else
+ ret = ublk_copy_user_pages(req, buf_off, iter, dir);

out:
ublk_put_req_ref(io, req);
return ret;
}
--
2.45.2