On Thu, Jan 05, 2023 at 07:07:34PM +0000, Keith Busch wrote:
> From: Keith Busch <kbusch@xxxxxxxxxx>
>
> This is more efficient that iter_iov.
>
> Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
> ---
> block/blk-map.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-map.c b/block/blk-map.c
> index 19940c978c73b..4cf83eae9f2e8 100644
> --- a/block/blk-map.c
> +++ b/block/blk-map.c
> @@ -641,7 +641,7 @@ int blk_rq_map_user_iov(struct request_queue *q, stru=
> ct request *rq,
> copy =3D true;
> else if (iov_iter_is_bvec(iter))
> map_bvec =3D true;
> - else if (!iter_is_iovec(iter))
> + else if (!user_backed_iter(iter))
> copy =3D true;
> else if (queue_virt_boundary(q))
> copy =3D queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
> @@ -682,9 +682,8 @@ int blk_rq_map_user(struct request_queue *q, struct r=
> equest *rq,
> struct rq_map_data *map_data, void __user *ubuf,
> unsigned long len, gfp_t gfp_mask)
> {
> - struct iovec iov;
> struct iov_iter i;
> - int ret =3D import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
> + int ret =3D import_ubuf(rq_data_dir(rq), ubuf, len, &i);
> =20
> if (unlikely(ret < 0))
> return ret;
> --=20
> 2.30.2
>
>
> --
Hello Keith,
It appears that this commit breaks SG_IO ioctl.
A git bisect returned the following commit:
commit a696647a3b58c7a2dddd6eabfc824be826613211
Author: Keith Busch <kbusch@xxxxxxxxxx>
Date: Thu Jan 5 11:07:34 2023 -0800
block: use iter_ubuf for single range
This is more efficient than iter_iov.
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
block/blk-map.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
When using linux-next tag next-20230111 :
$ sudo sg_inq /dev/sg0
sg_inq failed: Bad address
If I simply revert your commit
a696647a3b58 ("block: use iter_ubuf for single range"),
things start working again:
$ sudo sg_inq /dev/sg0
standard INQUIRY:
PQual=0 PDT=0 RMB=0 LU_CONG=0 hot_pluggable=0 version=0x05 [SPC-3]
[AERC=0] [TrmTsk=0] NormACA=0 HiSUP=0 Resp_data_format=2
SCCS=0 ACC=0 TPGS=0 3PC=0 Protect=0 [BQue=0]
EncServ=0 MultiP=0 [MChngr=0] [ACKREQQ=0] Addr16=0
[RelAdr=0] WBus16=0 Sync=0 [Linked=0] [TranDis=0] CmdQue=1
[SPI: Clocking=0x0 QAS=0 IUS=0]
length=96 (0x60) Peripheral device type: disk
Vendor identification: ATA
Product identification: QEMU HARDDISK
Product revision level: 2.5+
Unit serial number: QM00005
I'm quite surprised that we don't have any automated tests that
have caught/reported this already, as SG is quite heavily used.
Kind regards,
Niklas
