Re: [PATCH RFC v2 12/24] hpsa: use reserved commands

Ming Lei
2020-03-11T08:11:27Z

On Wed, Mar 11, 2020 at 12:25:38AM +0800, John Garry wrote:
> From: Hannes Reinecke <hare@suse.com>
>
> Enable the use of reserved commands, and drop the hand-crafted
> command allocation.
>
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
> drivers/scsi/hpsa.c | 147 ++++++++++++++------------------------------
> drivers/scsi/hpsa.h | 1 -
> 2 files changed, 45 insertions(+), 103 deletions(-)
>
> diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> index 703f824584fe..c14dd4b6e598 100644
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -244,10 +244,6 @@ static struct hpsa_scsi_dev_t
> *hpsa_find_device_by_sas_rphy(struct ctlr_info *h,
> struct sas_rphy *rphy);
>
> -#define SCSI_CMD_BUSY ((struct scsi_cmnd *)&hpsa_cmd_busy)
> -static const struct scsi_cmnd hpsa_cmd_busy;
> -#define SCSI_CMD_IDLE ((struct scsi_cmnd *)&hpsa_cmd_idle)
> -static const struct scsi_cmnd hpsa_cmd_idle;
> static int number_of_controllers;
>
> static irqreturn_t do_hpsa_intr_intx(int irq, void *dev_id);
> @@ -342,7 +338,7 @@ static inline struct ctlr_info *shost_to_hba(struct Scsi_Host *sh)
>
> static inline bool hpsa_is_cmd_idle(struct CommandList *c)
> {
> - return c->scsi_cmd == SCSI_CMD_IDLE;
> + return c->scsi_cmd == NULL;
> }
>
> /* extract sense key, asc, and ascq from sense data. -1 means invalid. */
> @@ -2445,7 +2441,12 @@ static void hpsa_cmd_resolve_events(struct ctlr_info *h,
> * this command has completed. Then, check to see if the handler is
> * waiting for this command, and, if so, wake it.
> */
> - c->scsi_cmd = SCSI_CMD_IDLE;
> + if (c->scsi_cmd && c->cmd_type == CMD_IOCTL_PEND) {
> + struct scsi_cmnd *scmd = c->scsi_cmd;
> +
> + scsi_put_reserved_cmd(scmd);
> + }
> + c->scsi_cmd = NULL;
> mb(); /* Declare command idle before checking for pending events. */
> if (dev) {
> atomic_dec(&dev->commands_outstanding);
> @@ -5502,7 +5503,6 @@ static void hpsa_cmd_init(struct ctlr_info *h, int index,
> c->ErrDesc.Addr = cpu_to_le64((u64) err_dma_handle);
> c->ErrDesc.Len = cpu_to_le32((u32) sizeof(*c->err_info));
> c->h = h;
> - c->scsi_cmd = SCSI_CMD_IDLE;
> }
>
> static void hpsa_preinitialize_commands(struct ctlr_info *h)
> @@ -5803,6 +5803,7 @@ static int hpsa_scsi_host_alloc(struct ctlr_info *h)
> sh->max_lun = HPSA_MAX_LUN;
> sh->max_id = HPSA_MAX_LUN;
> sh->can_queue = h->nr_cmds - HPSA_NRESERVED_CMDS;
> + sh->nr_reserved_cmds = HPSA_NRESERVED_CMDS;

Now .nr_reserved_cmds has been passed to blk-mq, you need to increase
sh->can_queue to h->nr_cmds, because .can_queue is the whole queue depth
(include the part of reserved tags), otherwise, IO tags will be
decreased.

Not look into other drivers, I guess they need such change too.

Thanks,
Ming