On 11/4/2021 5:33 AM, Damien Le Moal wrote:

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On 2021/11/04 15:46, Chaitanya Kulkarni wrote:

quoted

From: Chaitanya Kulkarni <kch@nvidia.com>

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
---
  drivers/scsi/sd.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++
  drivers/scsi/sd.h |  1 +
  2 files changed, 53 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a3d2d4bc4a3d..7f2c4eb98cf8 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c

@@ -106,6 +106,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_ZBC);

  static void sd_config_discard(struct scsi_disk *, unsigned int);
  static void sd_config_write_same(struct scsi_disk *);
+static void sd_config_verify(struct scsi_disk *sdkp);
  static int  sd_revalidate_disk(struct gendisk *);
  static void sd_unlock_native_capacity(struct gendisk *disk);
  static int  sd_probe(struct device *);

@@ -995,6 +996,41 @@ static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
       return sd_setup_write_same10_cmnd(cmd, false);
  }

+static void sd_config_verify(struct scsi_disk *sdkp)
+{
+     struct request_queue *q = sdkp->disk->queue;
+
+     /* XXX: use same pattern as sd_config_write_same(). */
+     blk_queue_max_verify_sectors(q, UINT_MAX >> 9);

VERIFY 10, 12, 16 and 32 commands are optional and may not be implemented by a
device. So setting this unconditionally is wrong.
At the very least you must have an "if (sdkp->verify_16)" here, and call
"blk_queue_max_verify_sectors(q, 0);" if the device does not support verify.

Yes, I put it together for the RFC, this needs to consider the device
unsupported case just like what we do for write zeroes and emulate the
same.

quoted

+}
+
+static blk_status_t sd_setup_verify_cmnd(struct scsi_cmnd *cmd)
+{
+       struct request *rq = cmd->request;
+       struct scsi_device *sdp = cmd->device;
+       struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
+       u64 lba = sectors_to_logical(sdp, blk_rq_pos(rq));
+       u32 nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
+
+       if (!sdkp->verify_16)
+            return BLK_STS_NOTSUPP;

I think this should be "return BLK_STS_TARGET;"

quoted

+
+       cmd->cmd_len = 16;
+       cmd->cmnd[0] = VERIFY_16;

And what if the device supports VERIFY 10 or 12 but not VERIFY 16 ?

For first implementation we can only VERIFY 16, later we can add cases 
for VERIFY 10-12 versions.

quoted

+       /* skip veprotect / dpo / bytchk */
+       cmd->cmnd[1] = 0;
+       put_unaligned_be64(lba, &cmd->cmnd[2]);
+       put_unaligned_be32(nr_blocks, &cmd->cmnd[10]);
+       cmd->cmnd[14] = 0;
+       cmd->cmnd[15] = 0;
+
+       cmd->allowed = SD_MAX_RETRIES;
+       cmd->sc_data_direction = DMA_NONE;
+       cmd->transfersize = 0;
+
+       return BLK_STS_OK;
+}
+
  static void sd_config_write_same(struct scsi_disk *sdkp)
  {
       struct request_queue *q = sdkp->disk->queue;

@@ -1345,6 +1381,8 @@ static blk_status_t sd_init_command(struct scsi_cmnd *cmd)
               }
       case REQ_OP_WRITE_ZEROES:
               return sd_setup_write_zeroes_cmnd(cmd);
+     case REQ_OP_VERIFY:
+             return sd_setup_verify_cmnd(cmd);
       case REQ_OP_WRITE_SAME:
               return sd_setup_write_same_cmnd(cmd);
       case REQ_OP_FLUSH:

@@ -2029,6 +2067,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
       switch (req_op(req)) {
       case REQ_OP_DISCARD:
       case REQ_OP_WRITE_ZEROES:
+     case REQ_OP_VERIFY:
       case REQ_OP_WRITE_SAME:
       case REQ_OP_ZONE_RESET:
       case REQ_OP_ZONE_RESET_ALL:

@@ -3096,6 +3135,17 @@ static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
               sdkp->ws10 = 1;
  }

+static void sd_read_verify(struct scsi_disk *sdkp, unsigned char *buffer)
+{
+       struct scsi_device *sdev = sdkp->device;
+
+       sd_printk(KERN_INFO, sdkp, "VERIFY16 check.\n");

Remove this message please.

quoted

+       if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, VERIFY_16) == 1) {
+            sd_printk(KERN_INFO, sdkp, " VERIFY16 in ON .\n");

And this one too.

quoted

+               sdkp->verify_16 = 1;

Why not checking for VERIFY 10 and 12 if VERIFY 16 is not supported ?
Also, why don't you call "blk_queue_max_verify_sectors(q, UINT_MAX >> 9);" here
instead of adding the not so useful sd_config_verify() helper ?

Okay, let me see if I can add that in V1.

quoted

+       }
+}
+
  static void sd_read_security(struct scsi_disk *sdkp, unsigned char *buffer)
  {
       struct scsi_device *sdev = sdkp->device;

@@ -3224,6 +3274,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
               sd_read_cache_type(sdkp, buffer);
               sd_read_app_tag_own(sdkp, buffer);
               sd_read_write_same(sdkp, buffer);
+             sd_read_verify(sdkp, buffer);
               sd_read_security(sdkp, buffer);
       }

@@ -3265,6 +3316,7 @@ static int sd_revalidate_disk(struct gendisk *disk)

       set_capacity_and_notify(disk, logical_to_sectors(sdp, sdkp->capacity));
       sd_config_write_same(sdkp);
+     sd_config_verify(sdkp);
       kfree(buffer);

       /*

diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index b59136c4125b..94a86bf6dac4 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h

@@ -120,6 +120,7 @@ struct scsi_disk {
       unsigned        lbpvpd : 1;
       unsigned        ws10 : 1;
       unsigned        ws16 : 1;
+     unsigned        verify_16 : 1;

See right above this line how write same supports the 10 and 16 variants. I
think you need the same here. And very likely, you also need the 32 version in
case the device has DIF/DIX (type 2 protection).

Agree with write same 10/16 versions, let me see if I can add that for V1.

quoted

       unsigned        rc_basis: 2;
       unsigned        zoned: 2;
       unsigned        urswrz : 1;

--
Damien Le Moal
Western Digital Research

Thanks for the comments Damien.