lkml.org 
[lkml]   [2022]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH RFC v2 04/18] scsi: core: Add support to send reserved commands
    Date
    Add a method to queue reserved commands.

    TODO:
    - fix timeout handler to call into reserved commands
    - We don't clear host_scribble for libata qc, but we should be able to drop
    this if we store libata qc in the scsi cmnd priv_data

    Signed-off-by: John Garry <john.garry@huawei.com>
    ---
    drivers/scsi/hosts.c | 6 ++++++
    drivers/scsi/scsi_lib.c | 32 ++++++++++++++++++++++++++++++++
    include/scsi/scsi_cmnd.h | 5 +++++
    include/scsi/scsi_host.h | 1 +
    4 files changed, 44 insertions(+)

    diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
    index 27296addaf63..5c9b05a8fec8 100644
    --- a/drivers/scsi/hosts.c
    +++ b/drivers/scsi/hosts.c
    @@ -221,6 +221,12 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
    goto fail;
    }

    + if (shost->nr_reserved_cmds && !sht->reserved_queuecommand) {
    + shost_printk(KERN_ERR, shost,
    + "nr_reserved_cmds set but no method to queue\n");
    + goto fail;
    + }
    +
    /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
    shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
    shost->can_queue);
    diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
    index f6e53c6d913c..8c8b4c6767d9 100644
    --- a/drivers/scsi/scsi_lib.c
    +++ b/drivers/scsi/scsi_lib.c
    @@ -1422,6 +1422,16 @@ static void scsi_complete(struct request *rq)
    struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
    enum scsi_disposition disposition;

    + if (scsi_is_reserved_cmd(cmd)) {
    + struct scsi_device *sdev = cmd->device;
    +
    + scsi_mq_uninit_cmd(cmd);
    + scsi_device_unbusy(sdev, cmd);
    + __blk_mq_end_request(rq, 0);
    +
    + return;
    + }
    +
    INIT_LIST_HEAD(&cmd->eh_entry);

    atomic_inc(&cmd->device->iodone_cnt);
    @@ -1706,6 +1716,28 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,

    WARN_ON_ONCE(cmd->budget_token < 0);

    + if (scsi_is_reserved_cmd(cmd)) {
    + unsigned char *host_scribble = cmd->host_scribble;
    +
    + if (!(req->rq_flags & RQF_DONTPREP)) {
    + ret = scsi_prepare_cmd(req);
    + if (ret != BLK_STS_OK) {
    +
    + goto out_dec_host_busy;
    + }
    +
    + req->rq_flags |= RQF_DONTPREP;
    + } else {
    + clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
    + }
    +
    + cmd->host_scribble = host_scribble;
    +
    + blk_mq_start_request(req);
    +
    + return shost->hostt->reserved_queuecommand(shost, cmd);
    + }
    +
    /*
    * If the device is not in running state we will reject some or all
    * commands.
    diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
    index 1e80e70dfa92..e47df5836070 100644
    --- a/include/scsi/scsi_cmnd.h
    +++ b/include/scsi/scsi_cmnd.h
    @@ -152,6 +152,11 @@ static inline void *scsi_cmd_priv(struct scsi_cmnd *cmd)
    return cmd + 1;
    }

    +static inline bool scsi_is_reserved_cmd(struct scsi_cmnd *cmd)
    +{
    + return blk_mq_is_reserved_rq(scsi_cmd_to_rq(cmd));
    +}
    +
    void scsi_done(struct scsi_cmnd *cmd);
    void scsi_done_direct(struct scsi_cmnd *cmd);

    diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
    index 149dcbd4125e..88c8504395c8 100644
    --- a/include/scsi/scsi_host.h
    +++ b/include/scsi/scsi_host.h
    @@ -73,6 +73,7 @@ struct scsi_host_template {
    * STATUS: REQUIRED
    */
    int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
    + int (* reserved_queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);

    /*
    * The commit_rqs function is used to trigger a hardware
    --
    2.26.2
    \
     
     \ /
      Last update: 2022-06-09 12:38    [W:3.528 / U:1.072 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site