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Commit eb5a7871 authored by Raghavendra Rao Ananta's avatar Raghavendra Rao Ananta
Browse files

haven: Convert the cap entry locks to spinlocks 



There's a potential chance that the clients can request to
send or receive the data from an interrupt context. Hence,
convert the cap_entry_lock from mutex to a spinlock.

Change-Id: Ic314a32f7a8007308c0a397e0cc44f16441c58d4
Signed-off-by: default avatarRaghavendra Rao Ananta <rananta@codeaurora.org>
Signed-off-by: default avatarMurali Nalajala <mnalajal@codeaurora.org>
parent 1264c046

drivers/virt/haven/hh_msgq.c

+25 −39
Original line number Diff line number Diff line
@@ -6,7 +6,6 @@ 


#include <linux/slab.h>

#include <linux/wait.h>

#include <linux/mutex.h>

#include <linux/module.h>

#include <linux/spinlock.h>

#include <linux/interrupt.h>
@@ -24,7 +23,7 @@ struct hh_msgq_desc { 


struct hh_msgq_cap_table {

	struct hh_msgq_desc *client_desc;

	struct mutex cap_entry_lock;

	spinlock_t cap_entry_lock;



	hh_capid_t tx_cap_id;

	hh_capid_t rx_cap_id;
@@ -132,8 +131,7 @@ int hh_msgq_recv(void *msgq_client_desc, 


	cap_table_entry = &hh_msgq_cap_table[client_desc->label];



	if (mutex_lock_interruptible(&cap_table_entry->cap_entry_lock))

		return -ERESTARTSYS;

	spin_lock(&cap_table_entry->cap_entry_lock);



	if (cap_table_entry->client_desc != client_desc) {

		pr_err("%s: Invalid client descriptor\n", __func__);
@@ -155,7 +153,7 @@ int hh_msgq_recv(void *msgq_client_desc, 
		goto err;

	}



	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);



	*buff = kzalloc(HH_MSGQ_MAX_MSG_SIZE_BYTES, GFP_KERNEL);

	if (!(*buff))
@@ -185,7 +183,7 @@ int hh_msgq_recv(void *msgq_client_desc, 
	return ret;



err:

	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);

	return ret;

}

EXPORT_SYMBOL(hh_msgq_recv);
@@ -254,8 +252,7 @@ int hh_msgq_send(void *msgq_client_desc, 


	cap_table_entry = &hh_msgq_cap_table[client_desc->label];



	if (mutex_lock_interruptible(&cap_table_entry->cap_entry_lock))

		return -ERESTARTSYS;

	spin_lock(&cap_table_entry->cap_entry_lock);



	if (cap_table_entry->client_desc != client_desc) {

		pr_err("%s: Invalid client descriptor\n", __func__);
@@ -277,13 +274,11 @@ int hh_msgq_send(void *msgq_client_desc, 
		goto err;

	}



	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);



	do {

		if (cap_table_entry->tx_full && (flags & HH_MSGQ_NONBLOCK)) {

			ret = -EAGAIN;

			goto err;

		}

		if (cap_table_entry->tx_full && (flags & HH_MSGQ_NONBLOCK))

			return -EAGAIN;



		if (wait_event_interruptible(cap_table_entry->tx_wq,

					!cap_table_entry->tx_full))
@@ -300,7 +295,7 @@ int hh_msgq_send(void *msgq_client_desc, 


	return ret;

err:

	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);

	return ret;

}

EXPORT_SYMBOL(hh_msgq_send);
@@ -320,40 +315,35 @@ void *hh_msgq_register(enum hh_msgq_label label) 
{

	struct hh_msgq_cap_table *cap_table_entry;

	struct hh_msgq_desc *client_desc;

	int ret;



	if (label < 0 || label >= HH_MSGQ_LABEL_MAX)

		return ERR_PTR(-EINVAL);



	cap_table_entry = &hh_msgq_cap_table[label];



	if (mutex_lock_interruptible(&cap_table_entry->cap_entry_lock))

		return ERR_PTR(-ERESTARTSYS);

	spin_lock(&cap_table_entry->cap_entry_lock);



	/* Multiple clients cannot register to the same label (msgq) */

	if (cap_table_entry->client_desc) {

		ret = -EBUSY;

		goto err;

		spin_unlock(&cap_table_entry->cap_entry_lock);

		return ERR_PTR(-EBUSY);

	}



	spin_unlock(&cap_table_entry->cap_entry_lock);



	client_desc = kzalloc(sizeof(*client_desc), GFP_KERNEL);

	if (!client_desc) {

		ret = ENOMEM;

		goto err;

	}

	if (!client_desc)

		return ERR_PTR(ENOMEM);



	client_desc->label = label;



	spin_lock(&cap_table_entry->cap_entry_lock);

	cap_table_entry->client_desc = client_desc;

	spin_unlock(&cap_table_entry->cap_entry_lock);



	pr_info("hh_msgq: Registered client for label: %d\n", label);



	mutex_unlock(&cap_table_entry->cap_entry_lock);

	return client_desc;



err:

	mutex_unlock(&cap_table_entry->cap_entry_lock);

	return ERR_PTR(ret);

}

EXPORT_SYMBOL(hh_msgq_register);
@@ -374,20 +364,19 @@ int hh_msgq_unregister(void *msgq_client_desc) 


	cap_table_entry = &hh_msgq_cap_table[client_desc->label];



	if (mutex_lock_interruptible(&cap_table_entry->cap_entry_lock))

		return -ERESTARTSYS;

	spin_lock(&cap_table_entry->cap_entry_lock);



	/* Is the client trying to free someone else's msgq? */

	if (cap_table_entry->client_desc != client_desc) {

		pr_err("%s: Trying to free invalid client descriptor!\n",

			__func__);

		mutex_unlock(&cap_table_entry->cap_entry_lock);

		spin_unlock(&cap_table_entry->cap_entry_lock);

		return -EINVAL;

	}



	cap_table_entry->client_desc = NULL;



	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);



	pr_info("%s: Unregistered client for label: %d\n",

		__func__, client_desc->label);
@@ -416,8 +405,7 @@ int hh_msgq_populate_cap_info(enum hh_msgq_label label, u64 cap_id, 


	cap_table_entry = &hh_msgq_cap_table[label];



	if (mutex_lock_interruptible(&cap_table_entry->cap_entry_lock))

		return -ERESTARTSYS;

	spin_lock(&cap_table_entry->cap_entry_lock);



	if (direction == HH_MSGQ_DIRECTION_TX) {

		ret = request_irq(irq, hh_msgq_tx_isr, 0,
@@ -441,7 +429,7 @@ int hh_msgq_populate_cap_info(enum hh_msgq_label label, u64 cap_id, 
		goto err;

	}



	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);



	pr_debug(

		"%s: label: %d; cap_id: %llu; dir: %d; irq: %d\n",
@@ -450,7 +438,7 @@ int hh_msgq_populate_cap_info(enum hh_msgq_label label, u64 cap_id, 
	return 0;



err:

	mutex_unlock(&cap_table_entry->cap_entry_lock);

	spin_unlock(&cap_table_entry->cap_entry_lock);

	return ret;

}

EXPORT_SYMBOL(hh_msgq_populate_cap_info);
@@ -468,8 +456,6 @@ static void hh_msgq_cleanup(int begin_idx) 


		kfree(cap_table_entry->tx_irq_name);

		kfree(cap_table_entry->rx_irq_name);



		mutex_destroy(&cap_table_entry->cap_entry_lock);

	}

}
@@ -490,7 +476,7 @@ static int __init hh_msgq_init(void) 
		init_waitqueue_head(&cap_table_entry->rx_wq);

		spin_lock_init(&cap_table_entry->tx_lock);

		spin_lock_init(&cap_table_entry->rx_lock);

		mutex_init(&cap_table_entry->cap_entry_lock);

		spin_lock_init(&cap_table_entry->cap_entry_lock);



		cap_table_entry->tx_irq_name = kasprintf(GFP_KERNEL,

							"hh_msgq_tx_%d", i);