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Commit 6f5184e9 authored by Amandeep Virk's avatar Amandeep Virk Committed by Gerrit - the friendly Code Review server
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soc: qcom: spcom: Fix pid management for shared channel 



In case of multi client support for channel access in
the spcom, ensure correct pid is saved upon client
registration and removed upon client deregistration.

Change-Id: I4ecd627aca87fdeb1e33b1cd08b988d0511e1908
Signed-off-by: default avatarAmandeep Virk <avirk@codeaurora.org>
parent ce8bff17

drivers/soc/qcom/spcom.c

+37 −19
Original line number Diff line number Diff line
@@ -176,7 +176,7 @@ struct spcom_channel { 
	uint8_t num_clients;           /* current number of clients     */

	struct mutex shared_sync_lock;



	u32 pid; /* debug only to find user space application */

	u32 pid[SPCOM_MAX_CHANNEL_CLIENTS];



	/* abort flags */

	bool rpmsg_abort;
@@ -341,7 +341,7 @@ static int spcom_init_channel(struct spcom_channel *ch, 
	ch->actual_rx_size = 0;

	ch->is_busy = false;

	ch->txn_id = INITIAL_TXN_ID; /* use non-zero nonce for debug */

	ch->pid = 0;

	memset(ch->pid, 0, sizeof(ch->pid));

	ch->rpmsg_abort = false;

	ch->rpmsg_rx_buf = NULL;

	ch->comm_role_undefined = true;
@@ -1388,6 +1388,7 @@ static int spcom_device_open(struct inode *inode, struct file *filp) 
	int ret;

	const char *name = file_to_filename(filp);

	u32 pid = current_pid();

	int i = 0;



	pr_debug("open file [%s]\n", name);
@@ -1425,23 +1426,23 @@ static int spcom_device_open(struct inode *inode, struct file *filp) 
	}

	/* max number of channel clients reached */

	if (ch->is_busy) {

		pr_err("channel [%s] is BUSY and has %d of clients, already in use by pid [%d]\n",

			name, ch->num_clients, ch->pid);

		pr_err("channel [%s] is BUSY and has %d of clients, already in use\n",

			name, ch->num_clients);

		mutex_unlock(&ch->lock);

		return -EBUSY;

	}



	/*

	 * if same active client trying to register again, this will fail.

	 * Note: in the case of shared channel and SPCOM_MAX_CHANNEL_CLIENTS > 2

	 * It possible to register with same pid if you are not the current

	 * active client

	 * if same client trying to register again, this will fail

	 */

	if (ch->pid == pid) {

		pr_err("client is already registered with channel[%s]\n", name);

	for (i = 0; i < SPCOM_MAX_CHANNEL_CLIENTS; i++) {

		if (ch->pid[i] == pid) {

			pr_err("client with pid [%d] is already registered with channel[%s]\n",

				pid, name);

			mutex_unlock(&ch->lock);

			return -EINVAL;

		}

	}



	if (ch->is_sharable) {

		ch->num_clients++;
@@ -1449,13 +1450,25 @@ static int spcom_device_open(struct inode *inode, struct file *filp) 
			ch->is_busy = true;

		else

			ch->is_busy = false;

		/* pid array has pid of all the registered client.

		 * If we reach here, the is_busy flag check above guarantees

		 * that we have atleast one non-zero pid index

		 */

		for (i = 0; i < SPCOM_MAX_CHANNEL_CLIENTS; i++) {

			if (ch->pid[i] == 0) {

				ch->pid[i] = pid;

				break;

			}

		}

	} else {

		ch->num_clients = 1;

		ch->is_busy = true;

		/* Only first index of pid is relevant in case of

		 * non-shareable

		 */

		ch->pid[0] = pid;

	}



	/* pid has the last registed client's pid */

	ch->pid = pid;

	mutex_unlock(&ch->lock);



	filp->private_data = ch;
@@ -1478,6 +1491,7 @@ static int spcom_device_release(struct inode *inode, struct file *filp) 
	struct spcom_channel *ch;

	const char *name = file_to_filename(filp);

	int ret = 0;

	int i = 0;



	if (strcmp(name, "unknown") == 0) {

		pr_err("name is unknown\n");
@@ -1508,6 +1522,13 @@ static int spcom_device_release(struct inode *inode, struct file *filp) 
		return 0;

	}



	for (i = 0; i < SPCOM_MAX_CHANNEL_CLIENTS; i++) {

		if (ch->pid[i] == current_pid()) {

			ch->pid[i] = 0;

			break;

		}

	}



	if (ch->num_clients > 1) {

		/*

		 * Shared client is trying to close channel,
@@ -1522,14 +1543,11 @@ static int spcom_device_release(struct inode *inode, struct file *filp) 
		}

		ch->num_clients--;

		ch->is_busy = false;

		if (ch->num_clients > 0) {

		mutex_unlock(&ch->lock);

		return 0;

	}

	}



	ch->is_busy = false;

	ch->pid = 0;

	ch->num_clients = 0;

	ch->active_pid = 0;