This converts ipr's queuecommand path to use percpu refcounts
rather than atomics.
Signed-off-by: Brian King <brk...@linux.vnet.ibm.com>
---
drivers/scsi/ipr.c | 111 ++++++++++++++++++++++++++++++++++++++++++-----------
drivers/scsi/ipr.h | 53 +++----------------------
2 files changed, 98 insertions(+), 66 deletions(-)
diff -puN drivers/scsi/ipr.h~ipr_lockless_percpu drivers/scsi/ipr.h
--- linux-2.6.git/drivers/scsi/ipr.h~ipr_lockless_percpu 2016-09-06
21:08:18.268234535 -0500
+++ linux-2.6.git-bjking1/drivers/scsi/ipr.h 2016-09-06 21:08:18.278234468
-0500
@@ -33,6 +33,7 @@
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/irq_poll.h>
+#include <linux/percpu-refcount.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
@@ -512,7 +513,6 @@ struct ipr_hrr_queue {
struct list_head hrrq_error_q;
spinlock_t _lock;
spinlock_t *lock;
- atomic_t active;
volatile u32 toggle_bit;
u32 size;
@@ -522,7 +522,6 @@ struct ipr_hrr_queue {
u8 ioa_is_dead:1;
u8 allow_cmds:1;
u8 removing_ioa:1;
- u8 is_active:1;
struct irq_poll iopoll;
};
@@ -1472,6 +1471,12 @@ enum ipr_sdt_state {
DUMP_OBTAINED
};
+struct ipr_ioa_ref_cnt {
+ struct percpu_ref ref;
+ int released;
+ struct ipr_ioa_cfg *ioa_cfg;
+};
+
/* Per-controller data */
struct ipr_ioa_cfg {
char eye_catcher[8];
@@ -1547,7 +1552,6 @@ struct ipr_ioa_cfg {
struct ipr_hrr_queue hrrq[IPR_MAX_HRRQ_NUM];
u32 hrrq_num;
atomic_t hrrq_index;
- atomic_t hrrq_active;
u16 identify_hrrq_index;
struct ipr_bus_attributes bus_attr[IPR_MAX_NUM_BUSES];
@@ -1592,6 +1596,7 @@ struct ipr_ioa_cfg {
int (*reset) (struct ipr_cmnd *);
struct ata_host ata_host;
+ struct ipr_ioa_ref_cnt *ioa_usage_counter;
char ipr_cmd_label[8];
#define IPR_CMD_LABEL "ipr_cmd"
u32 max_cmds;
@@ -1872,48 +1877,6 @@ static inline void ipr_free_cmd(struct i
ipr_cmd->hrrq->active_map);
}
-static inline void ipr_hrrq_activate(struct ipr_hrr_queue *hrrq)
-{
- if (!hrrq->is_active) {
- atomic_inc(&hrrq->active);
- atomic_inc(&hrrq->ioa_cfg->hrrq_active);
- hrrq->is_active = 1;
- }
-}
-
-static inline void ipr_hrrq_deactivate(struct ipr_hrr_queue *hrrq)
-{
- if (hrrq->is_active) {
- hrrq->is_active = 0;
-
- if (!atomic_dec_return(&hrrq->active))
- atomic_dec(&hrrq->ioa_cfg->hrrq_active);
- }
-}
-
-static inline int ipr_hrrq_enter(struct ipr_hrr_queue *hrrq)
-{
- return atomic_inc_not_zero(&hrrq->active);
-}
-
-static void ipr_reset_ioa_job(struct ipr_cmnd *);
-
-static inline void ipr_hrrq_exit(struct ipr_hrr_queue *hrrq)
-{
- unsigned long flags;
- struct ipr_ioa_cfg *ioa_cfg;
-
- if (!atomic_dec_return(&hrrq->active)) {
- ioa_cfg = hrrq->ioa_cfg;
-
- if (!atomic_dec_return(&ioa_cfg->hrrq_active)) {
- spin_lock_irqsave(ioa_cfg->host->host_lock, flags);
- ipr_reset_ioa_job(ioa_cfg->reset_cmd);
- spin_unlock_irqrestore(ioa_cfg->host->host_lock, flags);
- }
- }
-}
-
static inline struct ipr_cmnd* ipr_first_active_cmd(struct ipr_hrr_queue *hrrq)
{
int i = find_first_bit(hrrq->active_map, hrrq->size);
diff -puN drivers/scsi/ipr.c~ipr_lockless_percpu drivers/scsi/ipr.c
--- linux-2.6.git/drivers/scsi/ipr.c~ipr_lockless_percpu 2016-09-06
21:08:18.272234509 -0500
+++ linux-2.6.git-bjking1/drivers/scsi/ipr.c 2016-09-06 21:08:18.280234455
-0500
@@ -6511,7 +6511,7 @@ static int ipr_queuecommand(struct Scsi_
hrrq = &ioa_cfg->hrrq[hrrq_id];
- if (!ipr_hrrq_enter(hrrq)) {
+ if (!percpu_ref_tryget_live(&ioa_cfg->ioa_usage_counter->ref)) {
dev_info(&ioa_cfg->pdev->dev, "Failed to get a ref\n");
spin_lock_irqsave(hrrq->lock, hrrq_flags);
@@ -6529,7 +6529,7 @@ static int ipr_queuecommand(struct Scsi_
ipr_cmd = __ipr_get_free_ipr_cmnd(hrrq);
if (ipr_cmd == NULL) {
- ipr_hrrq_exit(hrrq);
+ percpu_ref_put(&ioa_cfg->ioa_usage_counter->ref);
return SCSI_MLQUEUE_HOST_BUSY;
}
@@ -6591,7 +6591,7 @@ static int ipr_queuecommand(struct Scsi_
ipr_free_cmd(ipr_cmd);
scsi_dma_unmap(scsi_cmd);
}
- ipr_hrrq_exit(hrrq);
+ percpu_ref_put(&ioa_cfg->ioa_usage_counter->ref);
return SCSI_MLQUEUE_HOST_BUSY;
}
@@ -6599,7 +6599,7 @@ static int ipr_queuecommand(struct Scsi_
ipr_trc_hook(ipr_cmd, IPR_TRACE_START, IPR_GET_RES_PHYS_LOC(res));
ipr_send_command(ipr_cmd);
- ipr_hrrq_exit(hrrq);
+ percpu_ref_put(&ioa_cfg->ioa_usage_counter->ref);
return 0;
}
@@ -7161,14 +7161,17 @@ static int ipr_ioa_reset_done(struct ipr
{
struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
struct ipr_resource_entry *res;
+ struct ipr_hrr_queue *hrrq;
int j;
ENTER;
ioa_cfg->in_reset_reload = 0;
+ hrrq = &ioa_cfg->hrrq[IPR_INIT_HRRQ];
+ if (!hrrq->ioa_is_dead && !hrrq->removing_ioa)
+ ioa_cfg->allow_cmds = 1;
for (j = 0; j < ioa_cfg->hrrq_num; j++) {
spin_lock(&ioa_cfg->hrrq[j]._lock);
ioa_cfg->hrrq[j].allow_cmds = 1;
- ipr_hrrq_activate(&ioa_cfg->hrrq[j]);
spin_unlock(&ioa_cfg->hrrq[j]._lock);
}
wmb();
@@ -7203,6 +7206,8 @@ static int ipr_ioa_reset_done(struct ipr
wake_up_all(&ioa_cfg->reset_wait_q);
spin_unlock_irq(ioa_cfg->host->host_lock);
+ if (ioa_cfg->allow_cmds)
+ percpu_ref_reinit(&ioa_cfg->ioa_usage_counter->ref);
scsi_unblock_requests(ioa_cfg->host);
ipr_send_back_failed_ops(ioa_cfg);
spin_lock_irq(ioa_cfg->host->host_lock);
@@ -9119,9 +9124,6 @@ static void ipr_reset_ioa_job(struct ipr
return;
}
- if (atomic_read(&ioa_cfg->hrrq_active))
- return;
-
if (IPR_IOASC_SENSE_KEY(ioasc)) {
rc = ipr_cmd->job_step_failed(ipr_cmd);
if (rc == IPR_RC_JOB_RETURN)
@@ -9134,6 +9136,48 @@ static void ipr_reset_ioa_job(struct ipr
} while (rc == IPR_RC_JOB_CONTINUE);
}
+static void ipr_ioa_usage_counter_release(struct percpu_ref *ref)
+{
+ struct ipr_ioa_ref_cnt *ioa_ref = (struct ipr_ioa_ref_cnt *)ref;
+ struct ipr_ioa_cfg *ioa_cfg = ioa_ref->ioa_cfg;
+ unsigned long lock_flags;
+
+ ENTER;
+ spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+ if (ioa_cfg->reset_cmd)
+ ipr_reset_ioa_job(ioa_cfg->reset_cmd);
+ spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+ LEAVE;
+}
+
+/**
+ * ipr_reset_quiesce_work - Quiesce queuecommand
+ * @work: work struct
+ *
+ * Description: Quiesce queuecommand.
+ *
+ **/
+static void ipr_reset_quiesce_work(struct work_struct *work)
+{
+ struct ipr_cmnd *ipr_cmd = container_of(work, struct ipr_cmnd, work);
+ struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
+ unsigned long lock_flags = 0;
+ int allow_cmds;
+ ENTER;
+
+ spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+ allow_cmds = ioa_cfg->allow_cmds;
+ ioa_cfg->allow_cmds = 0;
+ spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+
+ /* xxx add a timeout here? */
+ if (allow_cmds)
+ percpu_ref_kill(&ioa_cfg->ioa_usage_counter->ref);
+ else
+ ipr_ioa_usage_counter_release(&ioa_cfg->ioa_usage_counter->ref);
+ LEAVE;
+}
+
/**
* _ipr_initiate_ioa_reset - Initiate an adapter reset
* @ioa_cfg: ioa config struct
@@ -9159,7 +9203,6 @@ static void _ipr_initiate_ioa_reset(stru
for (i = 0; i < ioa_cfg->hrrq_num; i++) {
spin_lock(&ioa_cfg->hrrq[i]._lock);
ioa_cfg->hrrq[i].allow_cmds = 0;
- ipr_hrrq_deactivate(&ioa_cfg->hrrq[i]);
spin_unlock(&ioa_cfg->hrrq[i]._lock);
}
wmb();
@@ -9171,7 +9214,8 @@ static void _ipr_initiate_ioa_reset(stru
ipr_cmd->job_step = job_step;
ipr_cmd->u.shutdown_type = shutdown_type;
- ipr_reset_ioa_job(ipr_cmd);
+ INIT_WORK(&ipr_cmd->work, ipr_reset_quiesce_work);
+ queue_work(ioa_cfg->reset_work_q, &ipr_cmd->work);
}
/**
@@ -9346,7 +9390,6 @@ static void ipr_pci_perm_failure(struct
for (i = 0; i < ioa_cfg->hrrq_num; i++) {
spin_lock(&ioa_cfg->hrrq[i]._lock);
ioa_cfg->hrrq[i].allow_cmds = 0;
- ipr_hrrq_deactivate(&ioa_cfg->hrrq[i]);
spin_unlock(&ioa_cfg->hrrq[i]._lock);
}
wmb();
@@ -9403,6 +9446,7 @@ static int ipr_probe_ioa_part2(struct ip
spin_lock_irqsave(ioa_cfg->host->host_lock, host_lock_flags);
dev_dbg(&ioa_cfg->pdev->dev, "ioa_cfg adx: 0x%p\n", ioa_cfg);
ioa_cfg->probe_done = 1;
+ ioa_cfg->allow_cmds = 1;
if (ioa_cfg->needs_hard_reset) {
ioa_cfg->needs_hard_reset = 0;
ipr_initiate_ioa_reset(ioa_cfg, IPR_SHUTDOWN_NONE);
@@ -9540,6 +9584,8 @@ static void ipr_free_all_resources(struc
iounmap(ioa_cfg->hdw_dma_regs);
pci_release_regions(pdev);
ipr_free_mem(ioa_cfg);
+ percpu_ref_exit(&ioa_cfg->ioa_usage_counter->ref);
+ kfree(ioa_cfg->ioa_usage_counter);
scsi_host_put(ioa_cfg->host);
pci_disable_device(pdev);
LEAVE;
@@ -10146,11 +10192,21 @@ static int ipr_probe_ioa(struct pci_dev
goto out_scsi_host_put;
}
+ ioa_cfg->ioa_usage_counter =
kzalloc(sizeof(*ioa_cfg->ioa_usage_counter),
+ GFP_KERNEL);
+
+ if (!ioa_cfg->ioa_usage_counter) {
+ dev_err(&pdev->dev, "Failed to allocate ioa_usage_counter\n");
+ rc = -ENOMEM;
+ goto out_scsi_host_put;
+ }
+
/* set SIS 32 or SIS 64 */
ioa_cfg->sis64 = ioa_cfg->ipr_chip->sis_type == IPR_SIS64 ? 1 : 0;
ioa_cfg->chip_cfg = ioa_cfg->ipr_chip->cfg;
ioa_cfg->clear_isr = ioa_cfg->chip_cfg->clear_isr;
ioa_cfg->max_cmds = ioa_cfg->chip_cfg->max_cmds;
+ ioa_cfg->ioa_usage_counter->ioa_cfg = ioa_cfg;
if (ipr_transop_timeout)
ioa_cfg->transop_timeout = ipr_transop_timeout;
@@ -10163,13 +10219,24 @@ static int ipr_probe_ioa(struct pci_dev
ipr_init_ioa_cfg(ioa_cfg, host, pdev);
+ rc = percpu_ref_init(&ioa_cfg->ioa_usage_counter->ref,
+ ipr_ioa_usage_counter_release,
+ 0, GFP_KERNEL);
+
+ if (rc) {
+ dev_err(&pdev->dev,
+ "Couldn't initialize percpu counter\n");
+ kfree(ioa_cfg->ioa_usage_counter);
+ goto out_scsi_host_put;
+ }
+
ipr_regs_pci = pci_resource_start(pdev, 0);
rc = pci_request_regions(pdev, IPR_NAME);
if (rc < 0) {
dev_err(&pdev->dev,
"Couldn't register memory range of registers\n");
- goto out_scsi_host_put;
+ goto out_percpu_ref;
}
rc = pci_enable_device(pdev);
@@ -10373,18 +10440,18 @@ static int ipr_probe_ioa(struct pci_dev
(dev_id->device == PCI_DEVICE_ID_IBM_OBSIDIAN_E &&
!ioa_cfg->revid)) {
ioa_cfg->needs_warm_reset = 1;
ioa_cfg->reset = ipr_reset_slot_reset;
-
- ioa_cfg->reset_work_q = alloc_ordered_workqueue("ipr_reset_%d",
- WQ_MEM_RECLAIM,
host->host_no);
-
- if (!ioa_cfg->reset_work_q) {
- dev_err(&pdev->dev, "Couldn't register reset
workqueue\n");
- rc = -ENOMEM;
- goto out_free_sata_work_q;
- }
} else
ioa_cfg->reset = ipr_reset_start_bist;
+ ioa_cfg->reset_work_q = alloc_ordered_workqueue("ipr_reset_%d",
+ WQ_MEM_RECLAIM,
host->host_no);
+
+ if (!ioa_cfg->reset_work_q) {
+ dev_err(&pdev->dev, "Couldn't register reset workqueue\n");
+ rc = -ENOMEM;
+ goto out_free_sata_work_q;
+ }
+
spin_lock_irqsave(&ipr_driver_lock, driver_lock_flags);
list_add_tail(&ioa_cfg->queue, &ipr_ioa_head);
spin_unlock_irqrestore(&ipr_driver_lock, driver_lock_flags);
@@ -10411,6 +10478,8 @@ out_disable:
pci_disable_device(pdev);
out_release_regions:
pci_release_regions(pdev);
+out_percpu_ref:
+ percpu_ref_exit(&ioa_cfg->ioa_usage_counter->ref);
out_scsi_host_put:
scsi_host_put(host);
goto out;
_
------------------------------------------------------------------------------
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