Message ID | 1478522920-108145-3-git-send-email-john.garry@huawei.com (mailing list archive) |
---|---|
State | Accepted, archived |
Headers | show |
On Mon, Nov 7, 2016 at 8:48 PM, John Garry <john.garry@huawei.com> wrote: > From: Xiang Chen <chenxiang66@hisilicon.com> > > Currently slots are allocated from queues in a round-robin fashion. > This causes a problem for internal commands in device mode. For this > mode, we should ensure that the internal abort command is the last > command seen in the host for that device. We can only ensure this when > we place the internal abort command after the preceding commands for > device that in the same queue, as there is no order in which the host > will select a queue to execute the next command. Is there performance penalty, since only one queue is supported for a device. > > This queue restriction makes supporting scsi mq more tricky in > the future, but should not be a blocker. > > Note: Even though v1 hw does not support internal abort, the > allocation method is chosen to be the same for consistency. > > Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> > Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Zhangfei Gao <zhangfei.gao@linaro.org> -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 16/11/2016 01:41, Zhangfei Gao wrote: > On Mon, Nov 7, 2016 at 8:48 PM, John Garry <john.garry@huawei.com> wrote: >> From: Xiang Chen <chenxiang66@hisilicon.com> >> >> Currently slots are allocated from queues in a round-robin fashion. >> This causes a problem for internal commands in device mode. For this >> mode, we should ensure that the internal abort command is the last >> command seen in the host for that device. We can only ensure this when >> we place the internal abort command after the preceding commands for >> device that in the same queue, as there is no order in which the host >> will select a queue to execute the next command. > > Is there performance penalty, since only one queue is supported for a device. Hi Zhangfei, From testing I have not seen any noteable performance change. However, please note the comment on mq, below. Cheers, John > >> >> This queue restriction makes supporting scsi mq more tricky in >> the future, but should not be a blocker. >> >> Note: Even though v1 hw does not support internal abort, the >> allocation method is chosen to be the same for consistency. >> >> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> >> Signed-off-by: John Garry <john.garry@huawei.com> > > Reviewed-by: Zhangfei Gao <zhangfei.gao@linaro.org> > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > . > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h index 64046c5..bf59fab 100644 --- a/drivers/scsi/hisi_sas/hisi_sas.h +++ b/drivers/scsi/hisi_sas/hisi_sas.h @@ -150,7 +150,8 @@ struct hisi_sas_hw { struct domain_device *device); struct hisi_sas_device *(*alloc_dev)(struct domain_device *device); void (*sl_notify)(struct hisi_hba *hisi_hba, int phy_no); - int (*get_free_slot)(struct hisi_hba *hisi_hba, int *q, int *s); + int (*get_free_slot)(struct hisi_hba *hisi_hba, u32 dev_id, + int *q, int *s); void (*start_delivery)(struct hisi_hba *hisi_hba); int (*prep_ssp)(struct hisi_hba *hisi_hba, struct hisi_sas_slot *slot, int is_tmf, @@ -207,7 +208,6 @@ struct hisi_hba { struct hisi_sas_port port[HISI_SAS_MAX_PHYS]; int queue_count; - int queue; struct hisi_sas_slot *slot_prep; struct dma_pool *sge_page_pool; diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c index 9afc697..9f5ccc5 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_main.c +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c @@ -232,8 +232,8 @@ static int hisi_sas_task_prep(struct sas_task *task, struct hisi_hba *hisi_hba, rc = hisi_sas_slot_index_alloc(hisi_hba, &slot_idx); if (rc) goto err_out; - rc = hisi_hba->hw->get_free_slot(hisi_hba, &dlvry_queue, - &dlvry_queue_slot); + rc = hisi_hba->hw->get_free_slot(hisi_hba, sas_dev->device_id, + &dlvry_queue, &dlvry_queue_slot); if (rc) goto err_out_tag; @@ -987,8 +987,8 @@ static int hisi_sas_query_task(struct sas_task *task) rc = hisi_sas_slot_index_alloc(hisi_hba, &slot_idx); if (rc) goto err_out; - rc = hisi_hba->hw->get_free_slot(hisi_hba, &dlvry_queue, - &dlvry_queue_slot); + rc = hisi_hba->hw->get_free_slot(hisi_hba, sas_dev->device_id, + &dlvry_queue, &dlvry_queue_slot); if (rc) goto err_out_tag; diff --git a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c index c0ac49d..bbc5760 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c +++ b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c @@ -862,29 +862,23 @@ static int get_wideport_bitmap_v1_hw(struct hisi_hba *hisi_hba, int port_id) * The callpath to this function and upto writing the write * queue pointer should be safe from interruption. */ -static int get_free_slot_v1_hw(struct hisi_hba *hisi_hba, int *q, int *s) +static int get_free_slot_v1_hw(struct hisi_hba *hisi_hba, u32 dev_id, + int *q, int *s) { struct device *dev = &hisi_hba->pdev->dev; struct hisi_sas_dq *dq; u32 r, w; - int queue = hisi_hba->queue; - - while (1) { - dq = &hisi_hba->dq[queue]; - w = dq->wr_point; - r = hisi_sas_read32_relaxed(hisi_hba, - DLVRY_Q_0_RD_PTR + (queue * 0x14)); - if (r == (w+1) % HISI_SAS_QUEUE_SLOTS) { - queue = (queue + 1) % hisi_hba->queue_count; - if (queue == hisi_hba->queue) { - dev_warn(dev, "could not find free slot\n"); - return -EAGAIN; - } - continue; - } - break; + int queue = dev_id % hisi_hba->queue_count; + + dq = &hisi_hba->dq[queue]; + w = dq->wr_point; + r = hisi_sas_read32_relaxed(hisi_hba, + DLVRY_Q_0_RD_PTR + (queue * 0x14)); + if (r == (w+1) % HISI_SAS_QUEUE_SLOTS) { + dev_warn(dev, "could not find free slot\n"); + return -EAGAIN; } - hisi_hba->queue = (queue + 1) % hisi_hba->queue_count; + *q = queue; *s = w; return 0; diff --git a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c index 9e70e6d..cb19e73 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c +++ b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c @@ -1089,29 +1089,24 @@ static int get_wideport_bitmap_v2_hw(struct hisi_hba *hisi_hba, int port_id) * The callpath to this function and upto writing the write * queue pointer should be safe from interruption. */ -static int get_free_slot_v2_hw(struct hisi_hba *hisi_hba, int *q, int *s) +static int get_free_slot_v2_hw(struct hisi_hba *hisi_hba, u32 dev_id, + int *q, int *s) { struct device *dev = &hisi_hba->pdev->dev; struct hisi_sas_dq *dq; u32 r, w; - int queue = hisi_hba->queue; + int queue = dev_id % hisi_hba->queue_count; - while (1) { - dq = &hisi_hba->dq[queue]; - w = dq->wr_point; - r = hisi_sas_read32_relaxed(hisi_hba, - DLVRY_Q_0_RD_PTR + (queue * 0x14)); - if (r == (w+1) % HISI_SAS_QUEUE_SLOTS) { - queue = (queue + 1) % hisi_hba->queue_count; - if (queue == hisi_hba->queue) { - dev_warn(dev, "could not find free slot\n"); - return -EAGAIN; - } - continue; - } - break; + dq = &hisi_hba->dq[queue]; + w = dq->wr_point; + r = hisi_sas_read32_relaxed(hisi_hba, + DLVRY_Q_0_RD_PTR + (queue * 0x14)); + if (r == (w+1) % HISI_SAS_QUEUE_SLOTS) { + dev_warn(dev, "full queue=%d r=%d w=%d\n\n", + queue, r, w); + return -EAGAIN; } - hisi_hba->queue = (queue + 1) % hisi_hba->queue_count; + *q = queue; *s = w; return 0;