scsi: smartpqi: Convert to host_tagset

Add support for host_tagset.

Also move the reserved command slots to the end of the pool to eliminate an
addition operation for every SCSI request.

This patch was originally authored by Hannes Reinecke here:

Link: https://lore.kernel.org/linux-block/20191126131009.71726-8-hare@suse.de/
But we NAKed this patch because we wanted to fully test multipath
failover operations.

Suggested-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Scott Benesh <scott.benesh@microchip.com>
Reviewed-by: Scott Teel <scott.teel@microchip.com>
Reviewed-by: Mahesh Rajashekhara <Mahesh.Rajashekhara@microchip.com>
Reviewed-by: Mike McGowen <Mike.McGowen@microchip.com>
Reviewed-by: Kevin Barnett <kevin.barnett@microchip.com>
Signed-off-by: Don Brace <don.brace@microchip.com>
Link: https://lore.kernel.org/r/166793529811.322537.3294617845448383948.stgit@brunhilda
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/smartpqi/smartpqi.h b/drivers/scsi/smartpqi/smartpqi.h
index e550b12..8cdf4d2 100644 (file)
--- a/drivers/scsi/smartpqi/smartpqi.h
+++ b/drivers/scsi/smartpqi/smartpqi.h
@@ -1307,7 +1307,6 @@ struct pqi_ctrl_info {
        dma_addr_t      error_buffer_dma_handle;
        size_t          sg_chain_buffer_length;
        unsigned int    num_queue_groups;
-       u16             max_hw_queue_index;
        u16             num_elements_per_iq;
        u16             num_elements_per_oq;
        u16             max_inbound_iu_length_per_firmware;
@@ -1369,8 +1368,6 @@ struct pqi_ctrl_info {
        u64             sas_address;
 
        struct pqi_io_request *io_request_pool;
-       u16             next_io_request_slot;
-
        struct pqi_event events[PQI_NUM_SUPPORTED_EVENTS];
        struct work_struct event_work;
 

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index b971fbe..651dca5 100644 (file)
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -678,23 +678,36 @@ static inline void pqi_reinit_io_request(struct pqi_io_request *io_request)
        io_request->raid_bypass = false;
 }
 
-static struct pqi_io_request *pqi_alloc_io_request(
-       struct pqi_ctrl_info *ctrl_info)
+static inline struct pqi_io_request *pqi_alloc_io_request(struct pqi_ctrl_info *ctrl_info, struct scsi_cmnd *scmd)
 {
        struct pqi_io_request *io_request;
-       u16 i = ctrl_info->next_io_request_slot;        /* benignly racy */
+       u16 i;
 
-       while (1) {
+       if (scmd) { /* SML I/O request */
+               u32 blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
+
+               i = blk_mq_unique_tag_to_tag(blk_tag);
                io_request = &ctrl_info->io_request_pool[i];
-               if (atomic_inc_return(&io_request->refcount) == 1)
-                       break;
-               atomic_dec(&io_request->refcount);
-               i = (i + 1) % ctrl_info->max_io_slots;
+               if (atomic_inc_return(&io_request->refcount) > 1) {
+                       atomic_dec(&io_request->refcount);
+                       return NULL;
+               }
+       } else { /* IOCTL or driver internal request */
+               /*
+                * benignly racy - may have to wait for an open slot.
+                * command slot range is scsi_ml_can_queue -
+                *         [scsi_ml_can_queue + (PQI_RESERVED_IO_SLOTS - 1)]
+                */
+               i = 0;
+               while (1) {
+                       io_request = &ctrl_info->io_request_pool[ctrl_info->scsi_ml_can_queue + i];
+                       if (atomic_inc_return(&io_request->refcount) == 1)
+                               break;
+                       atomic_dec(&io_request->refcount);
+                       i = (i + 1) % PQI_RESERVED_IO_SLOTS;
+               }
        }
 
-       /* benignly racy */
-       ctrl_info->next_io_request_slot = (i + 1) % ctrl_info->max_io_slots;
-
        pqi_reinit_io_request(io_request);
 
        return io_request;
@@ -4586,7 +4599,7 @@ static int pqi_submit_raid_request_synchronous(struct pqi_ctrl_info *ctrl_info,
                goto out;
        }
 
-       io_request = pqi_alloc_io_request(ctrl_info);
+       io_request = pqi_alloc_io_request(ctrl_info, NULL);
 
        put_unaligned_le16(io_request->index,
                &(((struct pqi_raid_path_request *)request)->request_id));
@@ -5233,7 +5246,6 @@ static void pqi_calculate_queue_resources(struct pqi_ctrl_info *ctrl_info)
        }
 
        ctrl_info->num_queue_groups = num_queue_groups;
-       ctrl_info->max_hw_queue_index = num_queue_groups - 1;
 
        /*
         * Make sure that the max. inbound IU length is an even multiple
@@ -5567,7 +5579,9 @@ static inline int pqi_raid_submit_scsi_cmd(struct pqi_ctrl_info *ctrl_info,
 {
        struct pqi_io_request *io_request;
 
-       io_request = pqi_alloc_io_request(ctrl_info);
+       io_request = pqi_alloc_io_request(ctrl_info, scmd);
+       if (!io_request)
+               return SCSI_MLQUEUE_HOST_BUSY;
 
        return pqi_raid_submit_scsi_cmd_with_io_request(ctrl_info, io_request,
                device, scmd, queue_group);
@@ -5671,7 +5685,9 @@ static int pqi_aio_submit_io(struct pqi_ctrl_info *ctrl_info,
        struct pqi_scsi_dev *device;
 
        device = scmd->device->hostdata;
-       io_request = pqi_alloc_io_request(ctrl_info);
+       io_request = pqi_alloc_io_request(ctrl_info, scmd);
+       if (!io_request)
+               return SCSI_MLQUEUE_HOST_BUSY;
        io_request->io_complete_callback = pqi_aio_io_complete;
        io_request->scmd = scmd;
        io_request->raid_bypass = raid_bypass;
@@ -5743,7 +5759,10 @@ static  int pqi_aio_submit_r1_write_io(struct pqi_ctrl_info *ctrl_info,
        struct pqi_io_request *io_request;
        struct pqi_aio_r1_path_request *r1_request;
 
-       io_request = pqi_alloc_io_request(ctrl_info);
+       io_request = pqi_alloc_io_request(ctrl_info, scmd);
+       if (!io_request)
+               return SCSI_MLQUEUE_HOST_BUSY;
+
        io_request->io_complete_callback = pqi_aio_io_complete;
        io_request->scmd = scmd;
        io_request->raid_bypass = true;
@@ -5801,7 +5820,9 @@ static int pqi_aio_submit_r56_write_io(struct pqi_ctrl_info *ctrl_info,
        struct pqi_io_request *io_request;
        struct pqi_aio_r56_path_request *r56_request;
 
-       io_request = pqi_alloc_io_request(ctrl_info);
+       io_request = pqi_alloc_io_request(ctrl_info, scmd);
+       if (!io_request)
+               return SCSI_MLQUEUE_HOST_BUSY;
        io_request->io_complete_callback = pqi_aio_io_complete;
        io_request->scmd = scmd;
        io_request->raid_bypass = true;
@@ -5860,13 +5881,10 @@ static int pqi_aio_submit_r56_write_io(struct pqi_ctrl_info *ctrl_info,
 static inline u16 pqi_get_hw_queue(struct pqi_ctrl_info *ctrl_info,
        struct scsi_cmnd *scmd)
 {
-       u16 hw_queue;
-
-       hw_queue = blk_mq_unique_tag_to_hwq(blk_mq_unique_tag(scsi_cmd_to_rq(scmd)));
-       if (hw_queue > ctrl_info->max_hw_queue_index)
-               hw_queue = 0;
-
-       return hw_queue;
+       /*
+        * We are setting host_tagset = 1 during init.
+        */
+       return blk_mq_unique_tag_to_hwq(blk_mq_unique_tag(scsi_cmd_to_rq(scmd)));
 }
 
 static inline bool pqi_is_bypass_eligible_request(struct scsi_cmnd *scmd)
@@ -6268,7 +6286,7 @@ static int pqi_lun_reset(struct pqi_ctrl_info *ctrl_info, struct scsi_cmnd *scmd
        struct pqi_scsi_dev *device;
 
        device = scmd->device->hostdata;
-       io_request = pqi_alloc_io_request(ctrl_info);
+       io_request = pqi_alloc_io_request(ctrl_info, NULL);
        io_request->io_complete_callback = pqi_lun_reset_complete;
        io_request->context = &wait;