Re: [PATCH 33/47] cxlflash: use dedicated reset command in send_tmf()

Matthew R. Ochs
2017-06-28T16:29:24Z

Hi Hannes,

We actually just reworked these paths in a series that
was pulled in on Monday. While testing, I came across a
bug in that series and was planning on sending out a fix
for it. I'll include some patches that will ease the burden
of incorporating your EH updates for cxlflash.

Many thanks for leading this effort, it really helps to clean
up the SCSI EH paths! =)

-matt

> On Jun 28, 2017, at 3:32 AM, Hannes Reinecke <hare@suse.de> wrote:
>
> From: Hannes Reinecke <hare@suse.com>
>
> Reduce the queue depth by 1, and use this command as a dedicated
> reset command send_tmf().
>
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
> drivers/scsi/cxlflash/common.h | 3 ++-
> drivers/scsi/cxlflash/main.c | 23 ++++++++++++++++-------
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h
> index 6d95e8e..b2b3bdc 100644
> --- a/drivers/scsi/cxlflash/common.h
> +++ b/drivers/scsi/cxlflash/common.h
> @@ -54,7 +54,8 @@
>
> /* Command management definitions */
> #define CXLFLASH_MAX_CMDS 256
> -#define CXLFLASH_MAX_CMDS_PER_LUN CXLFLASH_MAX_CMDS
> +#define CXLFLASH_MAX_CMDS_PER_LUN CXLFLASH_MAX_CMDS - 1
> +#define CXLFLASH_RESET_CMD 255
>
> /* RRQ for master issued cmds */
> #define NUM_RRQ_ENTRY CXLFLASH_MAX_CMDS
> diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
> index 462e8fc..b33e3e7 100644
> --- a/drivers/scsi/cxlflash/main.c
> +++ b/drivers/scsi/cxlflash/main.c
> @@ -23,6 +23,7 @@
>
> #include <scsi/scsi_cmnd.h>
> #include <scsi/scsi_host.h>
> +#include <scsi/scsi_tcq.h>
> #include <uapi/scsi/cxlflash_ioctl.h>
>
> #include "main.h"
> @@ -460,15 +461,16 @@ static u32 cmd_to_target_hwq(struct Scsi_Host *host, struct scsi_cmnd *scp,
> /**
> * send_tmf() - sends a Task Management Function (TMF)
> * @afu: AFU to checkout from.
> - * @scp: SCSI command from stack describing target.
> + * @sdev: SCSI device to reset.
> * @tmfcmd: TMF command to send.
> *
> * Return:
> * 0 on success, SCSI_MLQUEUE_HOST_BUSY or -errno on failure
> */
> -static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)
> +static int send_tmf(struct afu *afu, struct scsi_device *sdev, u64 tmfcmd)
> {
> - struct Scsi_Host *host = scp->device->host;
> + struct scsi_cmnd *scp;
> + struct Scsi_Host *host = sdev->host;
> struct cxlflash_cfg *cfg = shost_priv(host);
> struct afu_cmd *cmd = NULL;
> struct device *dev = &cfg->dev->dev;
> @@ -498,14 +500,21 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)
> cfg->tmf_active = true;
> spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
>
> + scp = scsi_host_find_tag(host, CXLFLASH_RESET_CMD);
> + scp->device = sdev;
> + cmd = sc_to_afucz(scp);
> + hwq_index = cmd_to_target_hwq(host, scp, afu);
> + hwq = get_hwq(afu, hwq_index);
> +
> + cmd->scp = scp;
> cmd->parent = afu;
> cmd->cmd_tmf = true;
> cmd->hwq_index = hwq_index;
>
> cmd->rcb.ctx_id = hwq->ctx_hndl;
> cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
> - cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);
> - cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
> + cmd->rcb.port_sel = CHAN2PORTMASK(sdev->channel);
> + cmd->rcb.lun_id = lun_to_lunid(sdev->lun);
> cmd->rcb.req_flags = (SISL_REQ_FLAGS_PORT_LUN_ID |
> SISL_REQ_FLAGS_SUP_UNDERRUN |
> SISL_REQ_FLAGS_TMF_CMD);
> @@ -2448,7 +2457,7 @@ static int cxlflash_eh_device_reset_handler(struct scsi_cmnd *scp)
> retry:
> switch (cfg->state) {
> case STATE_NORMAL:
> - rcr = send_tmf(afu, scp, TMF_LUN_RESET);
> + rcr = send_tmf(afu, sdev, TMF_LUN_RESET);
> if (unlikely(rcr))
> rc = FAILED;
> break;
> @@ -3139,7 +3148,7 @@ static ssize_t mode_show(struct device *dev,
> .eh_host_reset_handler = cxlflash_eh_host_reset_handler,
> .change_queue_depth = cxlflash_change_queue_depth,
> .cmd_per_lun = CXLFLASH_MAX_CMDS_PER_LUN,
> - .can_queue = CXLFLASH_MAX_CMDS,
> + .can_queue = CXLFLASH_MAX_CMDS - 1,
> .cmd_size = sizeof(struct afu_cmd) + __alignof__(struct afu_cmd) - 1,
> .this_id = -1,
> .sg_tablesize = 1, /* No scatter gather support */
> --
> 1.8.5.6
>