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Commit c3485ee0 authored by Rob Herring's avatar Rob Herring Committed by Greg Kroah-Hartman
Browse files

tty_port: Add port client functions 



Introduce a client (upward direction) operations struct for tty_port
clients. Initially supported operations are for receiving data and write
wake-up. This will allow for having clients other than an ldisc.

Convert the calls to the ldisc to use the client ops as the default
operations.

Signed-off-by: default avatarRob Herring <robh@kernel.org>
Reviewed-By: default avatarSebastian Reichel <sre@kernel.org>
Tested-By: default avatarSebastian Reichel <sre@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a380ed46

drivers/tty/tty_buffer.c

+3 −14
Original line number Diff line number Diff line
@@ -437,7 +437,7 @@ int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p, 
EXPORT_SYMBOL_GPL(tty_ldisc_receive_buf);



static int

receive_buf(struct tty_ldisc *ld, struct tty_buffer *head, int count)

receive_buf(struct tty_port *port, struct tty_buffer *head, int count)

{

	unsigned char *p = char_buf_ptr(head, head->read);

	char	      *f = NULL;
@@ -445,7 +445,7 @@ receive_buf(struct tty_ldisc *ld, struct tty_buffer *head, int count) 
	if (~head->flags & TTYB_NORMAL)

		f = flag_buf_ptr(head, head->read);



	return tty_ldisc_receive_buf(ld, p, f, count);

	return port->client_ops->receive_buf(port, p, f, count);

}



/**
@@ -465,16 +465,6 @@ static void flush_to_ldisc(struct work_struct *work) 
{

	struct tty_port *port = container_of(work, struct tty_port, buf.work);

	struct tty_bufhead *buf = &port->buf;

	struct tty_struct *tty;

	struct tty_ldisc *disc;



	tty = READ_ONCE(port->itty);

	if (tty == NULL)

		return;



	disc = tty_ldisc_ref(tty);

	if (disc == NULL)

		return;



	mutex_lock(&buf->lock);
@@ -504,7 +494,7 @@ static void flush_to_ldisc(struct work_struct *work) 
			continue;

		}



		count = receive_buf(disc, head, count);

		count = receive_buf(port, head, count);

		if (!count)

			break;

		head->read += count;
@@ -512,7 +502,6 @@ static void flush_to_ldisc(struct work_struct *work) 


	mutex_unlock(&buf->lock);



	tty_ldisc_deref(disc);

}



/**

drivers/tty/tty_port.c

+40 −6
Original line number Diff line number Diff line
@@ -17,6 +17,44 @@ 
#include <linux/delay.h>

#include <linux/module.h>



static int tty_port_default_receive_buf(struct tty_port *port,

					const unsigned char *p,

					const unsigned char *f, size_t count)

{

	int ret;

	struct tty_struct *tty;

	struct tty_ldisc *disc;



	tty = READ_ONCE(port->itty);

	if (!tty)

		return 0;



	disc = tty_ldisc_ref(tty);

	if (!disc)

		return 0;



	ret = tty_ldisc_receive_buf(disc, p, (char *)f, count);



	tty_ldisc_deref(disc);



	return ret;

}



static void tty_port_default_wakeup(struct tty_port *port)

{

	struct tty_struct *tty = tty_port_tty_get(port);



	if (tty) {

		tty_wakeup(tty);

		tty_kref_put(tty);

	}

}



static const struct tty_port_client_operations default_client_ops = {

	.receive_buf = tty_port_default_receive_buf,

	.write_wakeup = tty_port_default_wakeup,

};



void tty_port_init(struct tty_port *port)

{

	memset(port, 0, sizeof(*port));
@@ -28,6 +66,7 @@ void tty_port_init(struct tty_port *port) 
	spin_lock_init(&port->lock);

	port->close_delay = (50 * HZ) / 100;

	port->closing_wait = (3000 * HZ) / 100;

	port->client_ops = &default_client_ops;

	kref_init(&port->kref);

}

EXPORT_SYMBOL(tty_port_init);
@@ -272,12 +311,7 @@ EXPORT_SYMBOL_GPL(tty_port_tty_hangup); 
 */

void tty_port_tty_wakeup(struct tty_port *port)

{

	struct tty_struct *tty = tty_port_tty_get(port);



	if (tty) {

		tty_wakeup(tty);

		tty_kref_put(tty);

	}

	port->client_ops->write_wakeup(port);

}

EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);

include/linux/tty.h

+8 −1
Original line number Diff line number Diff line
@@ -218,11 +218,17 @@ struct tty_port_operations { 
	void (*destruct)(struct tty_port *port);

};



struct tty_port_client_operations {

	int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);

	void (*write_wakeup)(struct tty_port *port);

};



struct tty_port {

	struct tty_bufhead	buf;		/* Locked internally */

	struct tty_struct	*tty;		/* Back pointer */

	struct tty_struct	*itty;		/* internal back ptr */

	const struct tty_port_operations *ops;	/* Port operations */

	const struct tty_port_client_operations *client_ops; /* Port client operations */

	spinlock_t		lock;		/* Lock protecting tty field */

	int			blocked_open;	/* Waiting to open */

	int			count;		/* Usage count */
@@ -241,6 +247,7 @@ struct tty_port { 
						   based drain is needed else

						   set to size of fifo */

	struct kref		kref;		/* Ref counter */

	void 			*client_data;

};



/* tty_port::iflags bits -- use atomic bit ops */