[PATCH v4 5/5] scsi: ufs: Ungate the clock synchronously

Bart Van Assche
2023-05-29T20:27:06Z

Ungating the clock asynchronously causes ufshcd_queuecommand() to return
SCSI_MLQUEUE_HOST_BUSY and hence causes commands to be requeued. This is
suboptimal. Allow ufshcd_queuecommand() to sleep such that clock ungating
does not trigger command requeuing. Remove the ufshcd_scsi_block_requests()
and ufshcd_scsi_unblock_requests() calls because these are no longer
needed. The flush_work(&hba->clk_gating.ungate_work) call is sufficient to
make the SCSI core wait for clock ungating to complete.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/ufs/core/ufs-sysfs.c | 2 +-
drivers/ufs/core/ufshcd-crypto.c | 2 +-
drivers/ufs/core/ufshcd.c | 86 ++++++++++----------------------
include/ufs/ufshcd.h | 2 +-
4 files changed, 30 insertions(+), 62 deletions(-)

diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c
index 883f0e44b54e..cdf3d5f2b77b 100644
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -168,7 +168,7 @@ static ssize_t auto_hibern8_show(struct device *dev,
}

pm_runtime_get_sync(hba->dev);
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
ahit = ufshcd_readl(hba, REG_AUTO_HIBERNATE_IDLE_TIMER);
ufshcd_release(hba);
pm_runtime_put_sync(hba->dev);
diff --git a/drivers/ufs/core/ufshcd-crypto.c b/drivers/ufs/core/ufshcd-crypto.c
index 198360fe5e8e..f2c4422cab86 100644
--- a/drivers/ufs/core/ufshcd-crypto.c
+++ b/drivers/ufs/core/ufshcd-crypto.c
@@ -24,7 +24,7 @@ static int ufshcd_program_key(struct ufs_hba *hba,
u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg);
int err = 0;

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);

if (hba->vops && hba->vops->program_key) {
err = hba->vops->program_key(hba, cfg, slot);
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index c2d9109102f3..d9b6da33842a 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1189,7 +1189,7 @@ static int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba,
bool timeout = false, do_last_check = false;
ktime_t start;

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
spin_lock_irqsave(hba->host->host_lock, flags);
/*
* Wait for all the outstanding tasks/transfer requests.
@@ -1310,7 +1310,7 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba, u64 timeout_us)
}

/* let's not get into low power until clock scaling is completed */
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);

out:
return ret;
@@ -1640,7 +1640,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
goto out;

ufshcd_rpm_get_sync(hba);
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);

hba->clk_scaling.is_enabled = value;

@@ -1723,7 +1723,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
spin_lock_irqsave(hba->host->host_lock, flags);
if (hba->clk_gating.state == CLKS_ON) {
spin_unlock_irqrestore(hba->host->host_lock, flags);
- goto unblock_reqs;
+ return;
}

spin_unlock_irqrestore(hba->host->host_lock, flags);
@@ -1746,25 +1746,21 @@ static void ufshcd_ungate_work(struct work_struct *work)
}
hba->clk_gating.is_suspended = false;
}
-unblock_reqs:
- ufshcd_scsi_unblock_requests(hba);
}

/**
* ufshcd_hold - Enable clocks that were gated earlier due to ufshcd_release.
* Also, exit from hibern8 mode and set the link as active.
* @hba: per adapter instance
- * @async: This indicates whether caller should ungate clocks asynchronously.
*/
-int ufshcd_hold(struct ufs_hba *hba, bool async)
+void ufshcd_hold(struct ufs_hba *hba)
{
- int rc = 0;
bool flush_result;
unsigned long flags;

if (!ufshcd_is_clkgating_allowed(hba) ||
!hba->clk_gating.is_initialized)
- goto out;
+ return;
spin_lock_irqsave(hba->host->host_lock, flags);
hba->clk_gating.active_reqs++;

@@ -1781,15 +1777,10 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
*/
if (ufshcd_can_hibern8_during_gating(hba) &&
ufshcd_is_link_hibern8(hba)) {
- if (async) {
- rc = -EAGAIN;
- hba->clk_gating.active_reqs--;
- break;
- }
spin_unlock_irqrestore(hba->host->host_lock, flags);
flush_result = flush_work(&hba->clk_gating.ungate_work);
if (hba->clk_gating.is_suspended && !flush_result)
- goto out;
+ return;
spin_lock_irqsave(hba->host->host_lock, flags);
goto start;
}
@@ -1811,21 +1802,14 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
hba->clk_gating.state = REQ_CLKS_ON;
trace_ufshcd_clk_gating(dev_name(hba->dev),
hba->clk_gating.state);
- if (queue_work(hba->clk_gating.clk_gating_workq,
- &hba->clk_gating.ungate_work))
- ufshcd_scsi_block_requests(hba);
+ queue_work(hba->clk_gating.clk_gating_workq,
+ &hba->clk_gating.ungate_work);
/*
* fall through to check if we should wait for this
* work to be done or not.
*/
fallthrough;
case REQ_CLKS_ON:
- if (async) {
- rc = -EAGAIN;
- hba->clk_gating.active_reqs--;
- break;
- }
-
spin_unlock_irqrestore(hba->host->host_lock, flags);
flush_work(&hba->clk_gating.ungate_work);
/* Make sure state is CLKS_ON before returning */
@@ -1837,8 +1821,6 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
break;
}
spin_unlock_irqrestore(hba->host->host_lock, flags);
-out:
- return rc;
}
EXPORT_SYMBOL_GPL(ufshcd_hold);

@@ -2070,7 +2052,7 @@ static void ufshcd_exit_clk_gating(struct ufs_hba *hba)
ufshcd_remove_clk_gating_sysfs(hba);

/* Ungate the clock if necessary. */
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
hba->clk_gating.is_initialized = false;
ufshcd_release(hba);

@@ -2468,7 +2450,7 @@ int ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
if (hba->quirks & UFSHCD_QUIRK_BROKEN_UIC_CMD)
return 0;

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
mutex_lock(&hba->uic_cmd_mutex);
ufshcd_add_delay_before_dme_cmd(hba);

@@ -2871,12 +2853,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)

WARN_ONCE(tag < 0 || tag >= hba->nutrs, "Invalid tag %d\n", tag);

- /*
- * Allows the UFS error handler to wait for prior ufshcd_queuecommand()
- * calls.
- */
- rcu_read_lock();
-
switch (hba->ufshcd_state) {
case UFSHCD_STATE_OPERATIONAL:
break;
@@ -2922,13 +2898,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)

hba->req_abort_count = 0;

- err = ufshcd_hold(hba, true);
- if (err) {
- err = SCSI_MLQUEUE_HOST_BUSY;
- goto out;
- }
- WARN_ON(ufshcd_is_clkgating_allowed(hba) &&
- (hba->clk_gating.state != CLKS_ON));
+ ufshcd_hold(hba);

lrbp = &hba->lrb[tag];
lrbp->cmd = cmd;
@@ -2956,8 +2926,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
ufshcd_send_command(hba, tag, hwq);

out:
- rcu_read_unlock();
-
if (ufs_trigger_eh()) {
unsigned long flags;

@@ -3251,7 +3219,7 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,

BUG_ON(!hba);

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
mutex_lock(&hba->dev_cmd.lock);
ufshcd_init_query(hba, &request, &response, opcode, idn, index,
selector);
@@ -3325,7 +3293,7 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode,
return -EINVAL;
}

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);

mutex_lock(&hba->dev_cmd.lock);
ufshcd_init_query(hba, &request, &response, opcode, idn, index,
@@ -3421,7 +3389,7 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba,
return -EINVAL;
}

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);

mutex_lock(&hba->dev_cmd.lock);
ufshcd_init_query(hba, &request, &response, opcode, idn, index,
@@ -4239,7 +4207,7 @@ int ufshcd_uic_change_pwr_mode(struct ufs_hba *hba, u8 mode)
uic_cmd.command = UIC_CMD_DME_SET;
uic_cmd.argument1 = UIC_ARG_MIB(PA_PWRMODE);
uic_cmd.argument3 = mode;
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
ret = ufshcd_uic_pwr_ctrl(hba, &uic_cmd);
ufshcd_release(hba);

@@ -4346,7 +4314,7 @@ void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit)
if (update &&
!pm_runtime_suspended(&hba->ufs_device_wlun->sdev_gendev)) {
ufshcd_rpm_get_sync(hba);
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
ufshcd_auto_hibern8_enable(hba);
ufshcd_release(hba);
ufshcd_rpm_put_sync(hba);
@@ -4939,7 +4907,7 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
int err = 0;
int retries;

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
mutex_lock(&hba->dev_cmd.lock);
for (retries = NOP_OUT_RETRIES; retries > 0; retries--) {
err = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_NOP,
@@ -6224,22 +6192,22 @@ static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
ufshcd_setup_vreg(hba, true);
ufshcd_config_vreg_hpm(hba, hba->vreg_info.vccq);
ufshcd_config_vreg_hpm(hba, hba->vreg_info.vccq2);
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
if (!ufshcd_is_clkgating_allowed(hba))
ufshcd_setup_clocks(hba, true);
ufshcd_release(hba);
pm_op = hba->is_sys_suspended ? UFS_SYSTEM_PM : UFS_RUNTIME_PM;
ufshcd_vops_resume(hba, pm_op);
} else {
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
if (ufshcd_is_clkscaling_supported(hba) &&
hba->clk_scaling.is_enabled)
ufshcd_suspend_clkscaling(hba);
ufshcd_clk_scaling_allow(hba, false);
}
ufshcd_scsi_block_requests(hba);
- /* Drain ufshcd_queuecommand() */
- synchronize_rcu();
+ /* Wait for ongoing ufshcd_queuecommand() calls to finish. */
+ blk_mq_wait_quiesce_done(&hba->host->tag_set);
cancel_work_sync(&hba->eeh_work);
}

@@ -6884,7 +6852,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
return PTR_ERR(req);

req->end_io_data = &wait;
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);

spin_lock_irqsave(host->host_lock, flags);

@@ -7120,7 +7088,7 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
cmd_type = DEV_CMD_TYPE_NOP;
fallthrough;
case UPIU_TRANSACTION_QUERY_REQ:
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
mutex_lock(&hba->dev_cmd.lock);
err = ufshcd_issue_devman_upiu_cmd(hba, req_upiu, rsp_upiu,
desc_buff, buff_len,
@@ -7186,7 +7154,7 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
u16 ehs_len;

/* Protects use of hba->reserved_slot. */
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
mutex_lock(&hba->dev_cmd.lock);
down_read(&hba->clk_scaling_lock);

@@ -7420,7 +7388,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)

WARN_ONCE(tag < 0, "Invalid tag %d\n", tag);

- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
/* If command is already aborted/completed, return FAILED. */
if (!(test_bit(tag, &hba->outstanding_reqs))) {
@@ -9412,7 +9380,7 @@ static int __ufshcd_wl_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
* If we can't transition into any of the low power modes
* just gate the clocks.
*/
- ufshcd_hold(hba, false);
+ ufshcd_hold(hba);
hba->clk_gating.is_suspended = true;

if (ufshcd_is_clkscaling_supported(hba))
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index db2e669985d5..40c537a3880b 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -1357,7 +1357,7 @@ void ufshcd_fixup_dev_quirks(struct ufs_hba *hba,
int ufshcd_read_string_desc(struct ufs_hba *hba, u8 desc_index,
u8 **buf, bool ascii);

-int ufshcd_hold(struct ufs_hba *hba, bool async);
+void ufshcd_hold(struct ufs_hba *hba);
void ufshcd_release(struct ufs_hba *hba);

void ufshcd_clkgate_delay_set(struct device *dev, unsigned long value);