On Fri, Jul 14, 2023 at 09:25:10AM +0200, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
>
> Add zoned storage support to ublk: report_zones and operations:
> - REQ_OP_ZONE_OPEN
> - REQ_OP_ZONE_CLOSE
> - REQ_OP_ZONE_FINISH
> - REQ_OP_ZONE_RESET
> - REQ_OP_ZONE_APPEND
>
> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
> communicate ALBA back to the kernel. Therefore ublk must be used with the
> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
> available. Without this feature, ublk will not allow zoned storage support.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> ---
...
> +/*
> + * Construct a zone report. The report request is carried in `struct
> + * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
> + * and shall indicate the first zone of the report. The `nr_sectors` shall
> + * indicate how many zones should be reported (divide by zone size to get number
> + * of zones in the report) and must be an integer multiple of the zone size. The
> + * report shall be delivered as a `struct blk_zone` array. To report fewer zones
> + * than requested, zero the last entry of the returned array.
> + */
> +#define UBLK_IO_OP_REPORT_ZONES 18
Actually, I meant the following delta change in V8 comment, then the UAPI
looks more clean & readable wrt. reporting how many zones in UBLK_IO_OP_REPORT_ZONES
and reusing ublksrv_io_cmd->addr.
Otherwise, this patchset looks fine.
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 5698f4575e05..454c852ed328 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -70,7 +70,7 @@ struct ublk_rq_data {
struct kref ref;
__u64 sector;
__u32 operation;
- __u32 nr_sectors;
+ __u32 nr_zones;
};
struct ublk_uring_cmd_pdu {
@@ -335,7 +335,7 @@ static int ublk_report_zones(struct gendisk *disk, sector_t sector,
pdu = blk_mq_rq_to_pdu(req);
pdu->operation = UBLK_IO_OP_REPORT_ZONES;
pdu->sector = sector;
- pdu->nr_sectors = zones_in_request * zone_size_sectors;
+ pdu->nr_zones = zones_in_request;
ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
GFP_KERNEL);
@@ -404,7 +404,7 @@ static blk_status_t ublk_setup_iod_zoned(struct ublk_queue *ubq,
switch (ublk_op) {
case UBLK_IO_OP_REPORT_ZONES:
iod->op_flags = ublk_op | ublk_req_build_flags(req);
- iod->nr_sectors = pdu->nr_sectors;
+ iod->nr_zones = pdu->nr_zones;
iod->start_sector = pdu->sector;
return BLK_STS_OK;
default:
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 4d97eb0f7d13..602a788a650e 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -249,11 +249,13 @@ struct ublksrv_ctrl_dev_info {
/*
* Construct a zone report. The report request is carried in `struct
* ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
- * and shall indicate the first zone of the report. The `nr_sectors` shall
- * indicate how many zones should be reported (divide by zone size to get number
- * of zones in the report) and must be an integer multiple of the zone size. The
- * report shall be delivered as a `struct blk_zone` array. To report fewer zones
- * than requested, zero the last entry of the returned array.
+ * and shall indicate the first zone of the report. The `nr_zones` shall
+ * indicate how many zones should be reported at most. The report shall be
+ * delivered as a `struct blk_zone` array. To report fewer zones than
+ * requested, zero the last entry of the returned array.
+ *
+ * So related definitions(blk_zone, blk_zone_cond, blk_zone_type, ...) in
+ * include/uapi/linux/blkzoned.h are part of ublk UAPI.
*/
#define UBLK_IO_OP_REPORT_ZONES 18
@@ -276,7 +278,10 @@ struct ublksrv_io_desc {
/* op: bit 0-7, flags: bit 8-31 */
__u32 op_flags;
- __u32 nr_sectors;
+ union {
+ __u32 nr_sectors;
+ __u32 nr_zones; /* for UBLK_IO_OP_REPORT_ZONES only */
+ };
/* start sector for this io */
__u64 start_sector;
@@ -308,6 +313,12 @@ struct ublksrv_io_cmd {
/*
* userspace buffer address in ublksrv daemon process, valid for
* FETCH* command only
+ *
+ * This field shouldn't be used if UBLK_F_USER_COPY is enabled,
+ * because userspace deals with data copy by pread()/pwrite() over
+ * /dev/ublkcN. But in case of UBLK_F_ZONED, 'addr' is re-used to
+ * pass back the allocated LBA for UBLK_IO_OP_ZONE_APPEND which
+ * actually depends on UBLK_F_USER_COPY
*/
__u64 addr;
};
Thanks,
Ming
