[PATCH v3 03/23] scsi: hisi_sas: optimise the usage of hisi_hba.lock

From: John Garry
Date: Wed May 31 2017 - 10:13:17 EST

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From: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>

Currently hisi_hba.lock is locked to deliver and receive a
command to/from any hw queue. This causes much
contention at high data-rates.

To boost performance, lock on a per queue basis for
sending and receiving commands to/from hw.

Certain critical regions still need to be locked in the delivery
and completion stages with hisi_hba.lock.

New element hisi_sas_device.dq is added to store the delivery
queue for a device, so it does not need to be needlessly
re-calculated for every task.

Signed-off-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
drivers/scsi/hisi_sas/hisi_sas.h | 9 ++---
drivers/scsi/hisi_sas/hisi_sas_main.c | 61 +++++++++++++++++++++++-----------
drivers/scsi/hisi_sas/hisi_sas_v1_hw.c | 23 +++++--------
drivers/scsi/hisi_sas/hisi_sas_v2_hw.c | 34 +++++++++----------
4 files changed, 71 insertions(+), 56 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index b4e96fa9..68ba7bd 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -102,6 +102,8 @@ struct hisi_sas_cq {

struct hisi_sas_dq {
struct hisi_hba *hisi_hba;
+ struct hisi_sas_slot *slot_prep;
+ spinlock_t lock;
int wr_point;
int id;
};
@@ -109,6 +111,7 @@ struct hisi_sas_dq {
struct hisi_sas_device {
struct hisi_hba *hisi_hba;
struct domain_device *sas_device;
+ struct hisi_sas_dq *dq;
struct list_head list;
u64 attached_phy;
atomic64_t running_req;
@@ -154,9 +157,8 @@ 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, u32 dev_id,
- int *q, int *s);
- void (*start_delivery)(struct hisi_hba *hisi_hba);
+ int (*get_free_slot)(struct hisi_hba *hisi_hba, struct hisi_sas_dq *dq);
+ void (*start_delivery)(struct hisi_sas_dq *dq);
int (*prep_ssp)(struct hisi_hba *hisi_hba,
struct hisi_sas_slot *slot, int is_tmf,
struct hisi_sas_tmf_task *tmf);
@@ -217,7 +219,6 @@ struct hisi_hba {
struct hisi_sas_port port[HISI_SAS_MAX_PHYS];

int queue_count;
- struct hisi_sas_slot *slot_prep;

struct dma_pool *sge_page_pool;
struct hisi_sas_device devices[HISI_SAS_MAX_DEVICES];
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 54e0cf2..b247220 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -179,10 +179,11 @@ static void hisi_sas_slot_abort(struct work_struct *work)
task->task_done(task);
}

-static int hisi_sas_task_prep(struct sas_task *task, struct hisi_hba *hisi_hba,
- int is_tmf, struct hisi_sas_tmf_task *tmf,
- int *pass)
+static int hisi_sas_task_prep(struct sas_task *task, struct hisi_sas_dq
+ *dq, int is_tmf, struct hisi_sas_tmf_task *tmf,
+ int *pass)
{
+ struct hisi_hba *hisi_hba = dq->hisi_hba;
struct domain_device *device = task->dev;
struct hisi_sas_device *sas_dev = device->lldd_dev;
struct hisi_sas_port *port;
@@ -240,18 +241,24 @@ static int hisi_sas_task_prep(struct sas_task *task, struct hisi_hba *hisi_hba,
} else
n_elem = task->num_scatter;

+ spin_lock_irqsave(&hisi_hba->lock, flags);
if (hisi_hba->hw->slot_index_alloc)
rc = hisi_hba->hw->slot_index_alloc(hisi_hba, &slot_idx,
device);
else
rc = hisi_sas_slot_index_alloc(hisi_hba, &slot_idx);
- if (rc)
+ if (rc) {
+ spin_unlock_irqrestore(&hisi_hba->lock, flags);
goto err_out;
- rc = hisi_hba->hw->get_free_slot(hisi_hba, sas_dev->device_id,
- &dlvry_queue, &dlvry_queue_slot);
+ }
+ spin_unlock_irqrestore(&hisi_hba->lock, flags);
+
+ rc = hisi_hba->hw->get_free_slot(hisi_hba, dq);
if (rc)
goto err_out_tag;

+ dlvry_queue = dq->id;
+ dlvry_queue_slot = dq->wr_point;
slot = &hisi_hba->slot_info[slot_idx];
memset(slot, 0, sizeof(struct hisi_sas_slot));

@@ -316,7 +323,7 @@ static int hisi_sas_task_prep(struct sas_task *task, struct hisi_hba *hisi_hba,
task->task_state_flags |= SAS_TASK_AT_INITIATOR;
spin_unlock_irqrestore(&task->task_state_lock, flags);

- hisi_hba->slot_prep = slot;
+ dq->slot_prep = slot;

atomic64_inc(&sas_dev->running_req);
++(*pass);
@@ -354,19 +361,22 @@ static int hisi_sas_task_exec(struct sas_task *task, gfp_t gfp_flags,
unsigned long flags;
struct hisi_hba *hisi_hba = dev_to_hisi_hba(task->dev);
struct device *dev = &hisi_hba->pdev->dev;
+ struct domain_device *device = task->dev;
+ struct hisi_sas_device *sas_dev = device->lldd_dev;
+ struct hisi_sas_dq *dq = sas_dev->dq;

if (unlikely(test_bit(HISI_SAS_RESET_BIT, &hisi_hba->flags)))
return -EINVAL;

/* protect task_prep and start_delivery sequence */
- spin_lock_irqsave(&hisi_hba->lock, flags);
- rc = hisi_sas_task_prep(task, hisi_hba, is_tmf, tmf, &pass);
+ spin_lock_irqsave(&dq->lock, flags);
+ rc = hisi_sas_task_prep(task, dq, is_tmf, tmf, &pass);
if (rc)
dev_err(dev, "task exec: failed[%d]!\n", rc);

if (likely(pass))
- hisi_hba->hw->start_delivery(hisi_hba);
- spin_unlock_irqrestore(&hisi_hba->lock, flags);
+ hisi_hba->hw->start_delivery(dq);
+ spin_unlock_irqrestore(&dq->lock, flags);

return rc;
}
@@ -421,12 +431,16 @@ static struct hisi_sas_device *hisi_sas_alloc_dev(struct domain_device *device)
spin_lock(&hisi_hba->lock);
for (i = 0; i < HISI_SAS_MAX_DEVICES; i++) {
if (hisi_hba->devices[i].dev_type == SAS_PHY_UNUSED) {
+ int queue = i % hisi_hba->queue_count;
+ struct hisi_sas_dq *dq = &hisi_hba->dq[queue];
+
hisi_hba->devices[i].device_id = i;
sas_dev = &hisi_hba->devices[i];
sas_dev->dev_status = HISI_SAS_DEV_NORMAL;
sas_dev->dev_type = device->dev_type;
sas_dev->hisi_hba = hisi_hba;
sas_dev->sas_device = device;
+ sas_dev->dq = dq;
INIT_LIST_HEAD(&hisi_hba->devices[i].list);
break;
}
@@ -1140,6 +1154,7 @@ static int hisi_sas_query_task(struct sas_task *task)
struct hisi_sas_slot *slot;
struct asd_sas_port *sas_port = device->port;
struct hisi_sas_cmd_hdr *cmd_hdr_base;
+ struct hisi_sas_dq *dq = sas_dev->dq;
int dlvry_queue_slot, dlvry_queue, n_elem = 0, rc, slot_idx;
unsigned long flags;

@@ -1152,14 +1167,22 @@ static int hisi_sas_query_task(struct sas_task *task)
port = to_hisi_sas_port(sas_port);

/* simply get a slot and send abort command */
+ spin_lock_irqsave(&hisi_hba->lock, flags);
rc = hisi_sas_slot_index_alloc(hisi_hba, &slot_idx);
- if (rc)
+ if (rc) {
+ spin_unlock_irqrestore(&hisi_hba->lock, flags);
goto err_out;
- rc = hisi_hba->hw->get_free_slot(hisi_hba, sas_dev->device_id,
- &dlvry_queue, &dlvry_queue_slot);
+ }
+ spin_unlock_irqrestore(&hisi_hba->lock, flags);
+
+ spin_lock_irqsave(&dq->lock, flags);
+ rc = hisi_hba->hw->get_free_slot(hisi_hba, dq);
if (rc)
goto err_out_tag;

+ dlvry_queue = dq->id;
+ dlvry_queue_slot = dq->wr_point;
+
slot = &hisi_hba->slot_info[slot_idx];
memset(slot, 0, sizeof(struct hisi_sas_slot));

@@ -1186,18 +1209,20 @@ static int hisi_sas_query_task(struct sas_task *task)
task->task_state_flags |= SAS_TASK_AT_INITIATOR;
spin_unlock_irqrestore(&task->task_state_lock, flags);

- hisi_hba->slot_prep = slot;
+ dq->slot_prep = slot;

atomic64_inc(&sas_dev->running_req);

/* send abort command to our chip */
- hisi_hba->hw->start_delivery(hisi_hba);
+ hisi_hba->hw->start_delivery(dq);
+ spin_unlock_irqrestore(&dq->lock, flags);

return 0;

err_out_tag:
hisi_sas_slot_index_free(hisi_hba, slot_idx);
err_out:
+ spin_unlock_irqrestore(&dq->lock, flags);
dev_err(dev, "internal abort task prep: failed[%d]!\n", rc);

return rc;
@@ -1221,7 +1246,6 @@ static int hisi_sas_query_task(struct sas_task *task)
struct hisi_sas_device *sas_dev = device->lldd_dev;
struct device *dev = &hisi_hba->pdev->dev;
int res;
- unsigned long flags;

if (!hisi_hba->hw->prep_abort)
return -EOPNOTSUPP;
@@ -1238,11 +1262,8 @@ static int hisi_sas_query_task(struct sas_task *task)
task->slow_task->timer.expires = jiffies + msecs_to_jiffies(110);
add_timer(&task->slow_task->timer);

- /* Lock as we are alloc'ing a slot, which cannot be interrupted */
- spin_lock_irqsave(&hisi_hba->lock, flags);
res = hisi_sas_internal_abort_task_exec(hisi_hba, sas_dev->device_id,
task, abort_flag, tag);
- spin_unlock_irqrestore(&hisi_hba->lock, flags);
if (res) {
del_timer(&task->slow_task->timer);
dev_err(dev, "internal task abort: executing internal task failed: %d\n",
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
index fc1c1b2..7d7d2a7 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
@@ -900,22 +900,17 @@ static int get_wideport_bitmap_v1_hw(struct hisi_hba *hisi_hba, int port_id)
return bitmap;
}

-/**
- * This function allocates across all queues to load balance.
- * Slots are allocated from queues in a round-robin fashion.
- *
+/*
* 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, u32 dev_id,
- int *q, int *s)
+static int
+get_free_slot_v1_hw(struct hisi_hba *hisi_hba, struct hisi_sas_dq *dq)
{
struct device *dev = &hisi_hba->pdev->dev;
- struct hisi_sas_dq *dq;
+ int queue = dq->id;
u32 r, w;
- 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));
@@ -924,16 +919,14 @@ static int get_free_slot_v1_hw(struct hisi_hba *hisi_hba, u32 dev_id,
return -EAGAIN;
}

- *q = queue;
- *s = w;
return 0;
}

-static void start_delivery_v1_hw(struct hisi_hba *hisi_hba)
+static void start_delivery_v1_hw(struct hisi_sas_dq *dq)
{
- int dlvry_queue = hisi_hba->slot_prep->dlvry_queue;
- int dlvry_queue_slot = hisi_hba->slot_prep->dlvry_queue_slot;
- struct hisi_sas_dq *dq = &hisi_hba->dq[dlvry_queue];
+ struct hisi_hba *hisi_hba = dq->hisi_hba;
+ int dlvry_queue = dq->slot_prep->dlvry_queue;
+ int dlvry_queue_slot = dq->slot_prep->dlvry_queue_slot;

dq->wr_point = ++dlvry_queue_slot % HISI_SAS_QUEUE_SLOTS;
hisi_sas_write32(hisi_hba, DLVRY_Q_0_WR_PTR + (dlvry_queue * 0x14),
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
index e241921..2607aac 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
@@ -695,6 +695,9 @@ hisi_sas_device *alloc_dev_quirk_v2_hw(struct domain_device *device)
if (sata_dev && (i & 1))
continue;
if (hisi_hba->devices[i].dev_type == SAS_PHY_UNUSED) {
+ int queue = i % hisi_hba->queue_count;
+ struct hisi_sas_dq *dq = &hisi_hba->dq[queue];
+
hisi_hba->devices[i].device_id = i;
sas_dev = &hisi_hba->devices[i];
sas_dev->dev_status = HISI_SAS_DEV_NORMAL;
@@ -702,6 +705,7 @@ hisi_sas_device *alloc_dev_quirk_v2_hw(struct domain_device *device)
sas_dev->hisi_hba = hisi_hba;
sas_dev->sas_device = device;
sas_dev->sata_idx = sata_idx;
+ sas_dev->dq = dq;
INIT_LIST_HEAD(&hisi_hba->devices[i].list);
break;
}
@@ -1454,22 +1458,17 @@ static int get_wideport_bitmap_v2_hw(struct hisi_hba *hisi_hba, int port_id)
return bitmap;
}

-/**
- * This function allocates across all queues to load balance.
- * Slots are allocated from queues in a round-robin fashion.
- *
+/*
* 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, u32 dev_id,
- int *q, int *s)
+static int
+get_free_slot_v2_hw(struct hisi_hba *hisi_hba, struct hisi_sas_dq *dq)
{
struct device *dev = &hisi_hba->pdev->dev;
- struct hisi_sas_dq *dq;
+ int queue = dq->id;
u32 r, w;
- 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));
@@ -1479,16 +1478,14 @@ static int get_free_slot_v2_hw(struct hisi_hba *hisi_hba, u32 dev_id,
return -EAGAIN;
}

- *q = queue;
- *s = w;
return 0;
}

-static void start_delivery_v2_hw(struct hisi_hba *hisi_hba)
+static void start_delivery_v2_hw(struct hisi_sas_dq *dq)
{
- int dlvry_queue = hisi_hba->slot_prep->dlvry_queue;
- int dlvry_queue_slot = hisi_hba->slot_prep->dlvry_queue_slot;
- struct hisi_sas_dq *dq = &hisi_hba->dq[dlvry_queue];
+ struct hisi_hba *hisi_hba = dq->hisi_hba;
+ int dlvry_queue = dq->slot_prep->dlvry_queue;
+ int dlvry_queue_slot = dq->slot_prep->dlvry_queue_slot;

dq->wr_point = ++dlvry_queue_slot % HISI_SAS_QUEUE_SLOTS;
hisi_sas_write32(hisi_hba, DLVRY_Q_0_WR_PTR + (dlvry_queue * 0x14),
@@ -2344,7 +2341,9 @@ static void slot_err_v2_hw(struct hisi_hba *hisi_hba,
spin_lock_irqsave(&task->task_state_lock, flags);
task->task_state_flags |= SAS_TASK_STATE_DONE;
spin_unlock_irqrestore(&task->task_state_lock, flags);
+ spin_lock_irqsave(&hisi_hba->lock, flags);
hisi_sas_slot_task_free(hisi_hba, task, slot);
+ spin_unlock_irqrestore(&hisi_hba->lock, flags);
sts = ts->stat;

if (task->task_done)
@@ -3162,13 +3161,14 @@ static void cq_tasklet_v2_hw(unsigned long val)
struct hisi_sas_complete_v2_hdr *complete_queue;
u32 rd_point = cq->rd_point, wr_point, dev_id;
int queue = cq->id;
+ struct hisi_sas_dq *dq = &hisi_hba->dq[queue];

if (unlikely(hisi_hba->reject_stp_links_msk))
phys_try_accept_stp_links_v2_hw(hisi_hba);

complete_queue = hisi_hba->complete_hdr[queue];

- spin_lock(&hisi_hba->lock);
+ spin_lock(&dq->lock);
wr_point = hisi_sas_read32(hisi_hba, COMPL_Q_0_WR_PTR +
(0x14 * queue));

@@ -3218,7 +3218,7 @@ static void cq_tasklet_v2_hw(unsigned long val)
/* update rd_point */
cq->rd_point = rd_point;
hisi_sas_write32(hisi_hba, COMPL_Q_0_RD_PTR + (0x14 * queue), rd_point);
- spin_unlock(&hisi_hba->lock);
+ spin_unlock(&dq->lock);
}

static irqreturn_t cq_interrupt_v2_hw(int irq_no, void *p)
--
1.9.1

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