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Commit 01c94004 authored by Asutosh Das's avatar Asutosh Das Committed by Gerrit - the friendly Code Review server
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scsi: ufs: serialize h8 and device command contexts 



There's a race between clock scaling and issuing dev
commands. Both these contexts can run simultaneously.
Add a synchronization for this to avoid hibernating
during scaling while issuing dev commands.

Change-Id: Ic53f59d65d480a1857798ddc492028d3b756ef84
Signed-off-by: default avatarAsutosh Das <asutoshd@codeaurora.org>
parent 85016969

drivers/scsi/ufs/ufshcd.c

+37 −20
Original line number Diff line number Diff line
@@ -3445,18 +3445,6 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, 
	int tag;

	struct completion wait;

	unsigned long flags;

	bool has_read_lock = false;



	/*

	 * May get invoked from shutdown and IOCTL contexts.

	 * In shutdown context, it comes in with lock acquired.

	 * In error recovery context, it may come with lock acquired.

	 */



	if (!ufshcd_is_shutdown_ongoing(hba) && !ufshcd_eh_in_progress(hba)) {

		down_read(&hba->lock);

		has_read_lock = true;

	}



	/*

	 * Get free slot, sleep if slots are unavailable.
@@ -3489,8 +3477,6 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, 
out_put_tag:

	ufshcd_put_dev_cmd_tag(hba, tag);

	wake_up(&hba->dev_cmd.tag_wq);

	if (has_read_lock)

		up_read(&hba->lock);

	return err;

}
@@ -3565,10 +3551,15 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode, 
	struct ufs_query_res *response = NULL;

	int err, index = 0, selector = 0;

	int timeout = QUERY_REQ_TIMEOUT;

	bool has_read_lock = false;



	BUG_ON(!hba);



	ufshcd_hold_all(hba);

	if (!ufshcd_is_shutdown_ongoing(hba) && !ufshcd_eh_in_progress(hba)) {

		down_read(&hba->lock);

		has_read_lock = true;

	}

	mutex_lock(&hba->dev_cmd.lock);

	ufshcd_init_query(hba, &request, &response, opcode, idn, index,

			selector);
@@ -3612,6 +3603,8 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode, 


out_unlock:

	mutex_unlock(&hba->dev_cmd.lock);

	if (has_read_lock)

		up_read(&hba->lock);

	ufshcd_release_all(hba);

	return err;

}
@@ -3634,6 +3627,7 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode, 
	struct ufs_query_req *request = NULL;

	struct ufs_query_res *response = NULL;

	int err;

	bool has_read_lock = false;



	BUG_ON(!hba);
@@ -3645,6 +3639,16 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode, 
		goto out;

	}



	/*

	 * May get invoked from shutdown and IOCTL contexts.

	 * In shutdown context, it comes in with lock acquired.

	 * In error recovery context, it may come with lock acquired.

	 */



	if (!ufshcd_is_shutdown_ongoing(hba) && !ufshcd_eh_in_progress(hba)) {

		down_read(&hba->lock);

		has_read_lock = true;

	}

	mutex_lock(&hba->dev_cmd.lock);

	ufshcd_init_query(hba, &request, &response, opcode, idn, index,

			selector);
@@ -3677,6 +3681,8 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode, 


out_unlock:

	mutex_unlock(&hba->dev_cmd.lock);

	if (has_read_lock)

		up_read(&hba->lock);

out:

	ufshcd_release_all(hba);

	return err;
@@ -3727,6 +3733,7 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba, 
	struct ufs_query_req *request = NULL;

	struct ufs_query_res *response = NULL;

	int err;

	bool has_read_lock = false;



	BUG_ON(!hba);
@@ -3745,6 +3752,10 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba, 
		goto out;

	}



	if (!ufshcd_is_shutdown_ongoing(hba) && !ufshcd_eh_in_progress(hba)) {

		down_read(&hba->lock);

		has_read_lock = true;

	}

	mutex_lock(&hba->dev_cmd.lock);

	ufshcd_init_query(hba, &request, &response, opcode, idn, index,

			selector);
@@ -3780,6 +3791,9 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba, 


out_unlock:

	mutex_unlock(&hba->dev_cmd.lock);

	if (has_read_lock)

		up_read(&hba->lock);



out:

	ufshcd_release_all(hba);

	return err;
@@ -5301,8 +5315,13 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba) 
{

	int err = 0;

	int retries;

	bool has_read_lock = false;



	ufshcd_hold_all(hba);

	if (!ufshcd_is_shutdown_ongoing(hba) && !ufshcd_eh_in_progress(hba)) {

		down_read(&hba->lock);

		has_read_lock = true;

	}

	mutex_lock(&hba->dev_cmd.lock);

	for (retries = NOP_OUT_RETRIES; retries > 0; retries--) {

		err = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_NOP,
@@ -5314,6 +5333,8 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba) 
		dev_dbg(hba->dev, "%s: error %d retrying\n", __func__, err);

	}

	mutex_unlock(&hba->dev_cmd.lock);

	if (has_read_lock)

		up_read(&hba->lock);

	ufshcd_release_all(hba);



	if (err)
@@ -10251,12 +10272,9 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up) 
		 * e.g. link_recovery. Hence, release the rw_sem

		 * before hibern8.

		 */

		up_write(&hba->lock);

		ret = ufshcd_uic_hibern8_enter(hba);

		down_write(&hba->lock);

		if (ret)

			/* link will be bad state so no need to scale_up_gear */

			return ret;

			goto scale_up_gear;

		ufshcd_custom_cmd_log(hba, "Hibern8-entered");

	}
@@ -10268,8 +10286,7 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up) 
	if (ufshcd_is_auto_hibern8_supported(hba)) {

		ret = ufshcd_uic_hibern8_exit(hba);

		if (ret)

			/* link will be bad state so no need to scale_up_gear */

			return ret;

			goto scale_up_gear;

		ufshcd_custom_cmd_log(hba, "Hibern8-Exited");

	}