[SCSI] ipr: Reduce queuecommand lock time

Reduce the amount of time the host lock is held in queuecommand
for improved performance.

[jejb: fix up checkpatch noise]
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 63 insertions, 27 deletions

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index dacc784ad2d6..b2994e2cf017 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -620,25 +620,39 @@ static void ipr_init_ipr_cmnd(struct ipr_cmnd *ipr_cmd)
 }
 
 /**
- * ipr_get_free_ipr_cmnd - Get a free IPR Cmnd block
+ * __ipr_get_free_ipr_cmnd - Get a free IPR Cmnd block
  * @ioa_cfg:    ioa config struct
  *
  * Return value:
  *      pointer to ipr command struct
  **/
 static
-struct ipr_cmnd *ipr_get_free_ipr_cmnd(struct ipr_ioa_cfg *ioa_cfg)
+struct ipr_cmnd *__ipr_get_free_ipr_cmnd(struct ipr_ioa_cfg *ioa_cfg)
 {
         struct ipr_cmnd *ipr_cmd;
 
         ipr_cmd = list_entry(ioa_cfg->free_q.next, struct ipr_cmnd, queue);
         list_del(&ipr_cmd->queue);
-        ipr_init_ipr_cmnd(ipr_cmd);
 
         return ipr_cmd;
 }
 
 /**
+ * ipr_get_free_ipr_cmnd - Get a free IPR Cmnd block and initialize it
+ * @ioa_cfg:    ioa config struct
+ *
+ * Return value:
+ *      pointer to ipr command struct
+ **/
+static
+struct ipr_cmnd *ipr_get_free_ipr_cmnd(struct ipr_ioa_cfg *ioa_cfg)
+{
+        struct ipr_cmnd *ipr_cmd = __ipr_get_free_ipr_cmnd(ioa_cfg);
+        ipr_init_ipr_cmnd(ipr_cmd);
+        return ipr_cmd;
+}
+
+/**
  * ipr_mask_and_clear_interrupts - Mask all and clear specified interrupts
  * @ioa_cfg:    ioa config struct
  * @clr_ints:     interrupts to clear
@@ -5783,8 +5797,8 @@ static void ipr_scsi_done(struct ipr_cmnd *ipr_cmd)
 
 /**
  * ipr_queuecommand - Queue a mid-layer request
+ * @shost:              scsi host struct
  * @scsi_cmd:   scsi command struct
- * @done:               done function
  *
  * This function queues a request generated by the mid-layer.
  *
@@ -5793,61 +5807,58 @@ static void ipr_scsi_done(struct ipr_cmnd *ipr_cmd)
  *      SCSI_MLQUEUE_DEVICE_BUSY if device is busy
  *      SCSI_MLQUEUE_HOST_BUSY if host is busy
  **/
-static int ipr_queuecommand_lck(struct scsi_cmnd *scsi_cmd,
-                            void (*done) (struct scsi_cmnd *))
+static int ipr_queuecommand(struct Scsi_Host *shost,
+                            struct scsi_cmnd *scsi_cmd)
 {
         struct ipr_ioa_cfg *ioa_cfg;
         struct ipr_resource_entry *res;
         struct ipr_ioarcb *ioarcb;
         struct ipr_cmnd *ipr_cmd;
+        unsigned long lock_flags;
         int rc = 0;
 
-        scsi_cmd->scsi_done = done;
-        ioa_cfg = (struct ipr_ioa_cfg *)scsi_cmd->device->host->hostdata;
-        res = scsi_cmd->device->hostdata;
+        ioa_cfg = (struct ipr_ioa_cfg *)shost->hostdata;
+
+        spin_lock_irqsave(shost->host_lock, lock_flags);
         scsi_cmd->result = (DID_OK << 16);
+        res = scsi_cmd->device->hostdata;
 
         /*
          * We are currently blocking all devices due to a host reset
          * We have told the host to stop giving us new requests, but
          * ERP ops don't count. FIXME
          */
-        if (unlikely(!ioa_cfg->allow_cmds && !ioa_cfg->ioa_is_dead))
+        if (unlikely(!ioa_cfg->allow_cmds && !ioa_cfg->ioa_is_dead)) {
+                spin_unlock_irqrestore(shost->host_lock, lock_flags);
                 return SCSI_MLQUEUE_HOST_BUSY;
+        }
 
         /*
          * FIXME - Create scsi_set_host_offline interface
          *  and the ioa_is_dead check can be removed
          */
         if (unlikely(ioa_cfg->ioa_is_dead || !res)) {
-                memset(scsi_cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
-                scsi_cmd->result = (DID_NO_CONNECT << 16);
-                scsi_cmd->scsi_done(scsi_cmd);
-                return 0;
+                spin_unlock_irqrestore(shost->host_lock, lock_flags);
+                goto err_nodev;
         }
 
         if (ipr_is_gata(res) && res->sata_port)
                 return ata_sas_queuecmd(scsi_cmd, res->sata_port->ap);
 
-        ipr_cmd = ipr_get_free_ipr_cmnd(ioa_cfg);
+        ipr_cmd = __ipr_get_free_ipr_cmnd(ioa_cfg);
+        spin_unlock_irqrestore(shost->host_lock, lock_flags);
+
+        ipr_init_ipr_cmnd(ipr_cmd);
         ioarcb = &ipr_cmd->ioarcb;
-        list_add_tail(&ipr_cmd->queue, &ioa_cfg->pending_q);
 
         memcpy(ioarcb->cmd_pkt.cdb, scsi_cmd->cmnd, scsi_cmd->cmd_len);
         ipr_cmd->scsi_cmd = scsi_cmd;
-        ioarcb->res_handle = res->res_handle;
         ipr_cmd->done = ipr_scsi_done;
-        ipr_trc_hook(ipr_cmd, IPR_TRACE_START, IPR_GET_RES_PHYS_LOC(res));
 
         if (ipr_is_gscsi(res) || ipr_is_vset_device(res)) {
                 if (scsi_cmd->underflow == 0)
                         ioarcb->cmd_pkt.flags_hi |= IPR_FLAGS_HI_NO_ULEN_CHK;
 
-                if (res->needs_sync_complete) {
-                        ioarcb->cmd_pkt.flags_hi |= IPR_FLAGS_HI_SYNC_COMPLETE;
-                        res->needs_sync_complete = 0;
-                }
-
                 ioarcb->cmd_pkt.flags_hi |= IPR_FLAGS_HI_NO_LINK_DESC;
                 if (ipr_is_gscsi(res))
                         ioarcb->cmd_pkt.flags_lo |= IPR_FLAGS_LO_DELAY_AFTER_RST;
@@ -5866,16 +5877,41 @@ static int ipr_queuecommand_lck(struct scsi_cmnd *scsi_cmd,
                         rc = ipr_build_ioadl(ioa_cfg, ipr_cmd);
         }
 
-        if (unlikely(rc != 0)) {
-                list_move_tail(&ipr_cmd->queue, &ioa_cfg->free_q);
+        spin_lock_irqsave(shost->host_lock, lock_flags);
+        if (unlikely(rc || (!ioa_cfg->allow_cmds && !ioa_cfg->ioa_is_dead))) {
+                list_add_tail(&ipr_cmd->queue, &ioa_cfg->free_q);
+                spin_unlock_irqrestore(shost->host_lock, lock_flags);
+                if (!rc)
+                        scsi_dma_unmap(scsi_cmd);
                 return SCSI_MLQUEUE_HOST_BUSY;
         }
 
+        if (unlikely(ioa_cfg->ioa_is_dead)) {
+                list_add_tail(&ipr_cmd->queue, &ioa_cfg->free_q);
+                spin_unlock_irqrestore(shost->host_lock, lock_flags);
+                scsi_dma_unmap(scsi_cmd);
+                goto err_nodev;
+        }
+
+        ioarcb->res_handle = res->res_handle;
+        if (res->needs_sync_complete) {
+                ioarcb->cmd_pkt.flags_hi |= IPR_FLAGS_HI_SYNC_COMPLETE;
+                res->needs_sync_complete = 0;
+        }
+        list_add_tail(&ipr_cmd->queue, &ioa_cfg->pending_q);
+        ipr_trc_hook(ipr_cmd, IPR_TRACE_START, IPR_GET_RES_PHYS_LOC(res));
         ipr_send_command(ipr_cmd);
+        spin_unlock_irqrestore(shost->host_lock, lock_flags);
         return 0;
-}
 
-static DEF_SCSI_QCMD(ipr_queuecommand)
+err_nodev:
+        spin_lock_irqsave(shost->host_lock, lock_flags);
+        memset(scsi_cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+        scsi_cmd->result = (DID_NO_CONNECT << 16);
+        scsi_cmd->scsi_done(scsi_cmd);
+        spin_unlock_irqrestore(shost->host_lock, lock_flags);
+        return 0;
+}
 
 /**
  * ipr_ioctl - IOCTL handler