Commit 964105b5 authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
Browse files

TTY: simserial, remove support of shared interrupts 



It never worked there. The ISR was never written for that kind of
stuff. So remove all that crap with a hash of linked lists and pass
the pointer directly to the ISR.

BTW this answers the question there:
  * I don't know exactly why they don't use the dev_id opaque data
  * pointer instead of this extra lookup table

-> Because they thought they will support more devices bound to a
single interrupt w/o IRQF_SHARED. They would need exactly the hash
there.

What I don't understand is rebinding of the interrupt in the shutdown
path. They perhaps meant to do just synchronize_irq? In any case, this
is all gone and free_irq there properly.

By removing the hash we save some bits (exactly NR_IRQS * 8 bytes of
.bss and over a kilo of .text):
before:
   text    data     bss     dec     hex filename
  19600     320    8227   28147    6df3 ../a/ia64/arch/ia64/hp/sim/simserial.o
after:
   text    data     bss     dec     hex filename
  18568     320      28   18916    49e4 ../a/ia64/arch/ia64/hp/sim/simserial.o

Note that a shared interrupt could not work too. request_irq requires
data parameter to be non-NULL. So the whole IRQ_T exercise was
pointless.

Finally, this helps us remove another two members of async_struct :).

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d8522563

arch/ia64/hp/sim/simserial.c

+7 −57
Original line number Diff line number Diff line
@@ -92,8 +92,6 @@ static struct serial_uart_config uart_config[] = { 


struct tty_driver *hp_simserial_driver;



static struct async_struct *IRQ_ports[NR_IRQS];



static struct console *console;



static unsigned char *tmp_buf;
@@ -167,14 +165,9 @@ static void receive_chars(struct tty_struct *tty) 
 */

static irqreturn_t rs_interrupt_single(int irq, void *dev_id)

{

	struct async_struct * info;

	struct async_struct *info = dev_id;



	/*

	 * I don't know exactly why they don't use the dev_id opaque data

	 * pointer instead of this extra lookup table

	 */

	info = IRQ_ports[irq];

	if (!info || !info->tty) {

	if (!info->tty) {

		printk(KERN_INFO "simrs_interrupt_single: info|tty=0 info=%p problem\n", info);

		return IRQ_NONE;

	}
@@ -456,7 +449,6 @@ static void shutdown(struct async_struct * info) 
{

	unsigned long	flags;

	struct serial_state *state = info->state;

	int		retval;



	if (!(state->flags & ASYNC_INITIALIZED))

		return;
@@ -468,33 +460,8 @@ static void shutdown(struct async_struct * info) 


	local_irq_save(flags);

	{

		/*

		 * First unlink the serial port from the IRQ chain...

		 */

		if (info->next_port)

			info->next_port->prev_port = info->prev_port;

		if (info->prev_port)

			info->prev_port->next_port = info->next_port;

		else

			IRQ_ports[state->irq] = info->next_port;



		/*

		 * Free the IRQ, if necessary

		 */

		if (state->irq && (!IRQ_ports[state->irq] ||

				   !IRQ_ports[state->irq]->next_port)) {

			if (IRQ_ports[state->irq]) {

				free_irq(state->irq, NULL);

				retval = request_irq(state->irq, rs_interrupt_single,

						     IRQ_T(state), "serial",

						     NULL);



				if (retval)

					printk(KERN_ERR "serial shutdown: request_irq: error %d"

					       "  Couldn't reacquire IRQ.\n", retval);

			} else

				free_irq(state->irq, NULL);

		}

		if (state->irq)

			free_irq(state->irq, info);



		if (info->xmit.buf) {

			free_page((unsigned long) info->xmit.buf);
@@ -645,7 +612,6 @@ startup(struct async_struct *info) 
{

	unsigned long flags;

	int	retval=0;

	irq_handler_t handler;

	struct serial_state *state= info->state;

	unsigned long page;
@@ -677,29 +643,13 @@ startup(struct async_struct *info) 
	/*

	 * Allocate the IRQ if necessary

	 */

	if (state->irq && (!IRQ_ports[state->irq] ||

			  !IRQ_ports[state->irq]->next_port)) {

		if (IRQ_ports[state->irq]) {

			retval = -EBUSY;

			goto errout;

		} else

			handler = rs_interrupt_single;



		retval = request_irq(state->irq, handler, IRQ_T(state),

				"simserial", NULL);

	if (state->irq) {

		retval = request_irq(state->irq, rs_interrupt_single,

				IRQ_T(state), "simserial", info);

		if (retval)

			goto errout;

	}



	/*

	 * Insert serial port into IRQ chain.

	 */

	info->prev_port = NULL;

	info->next_port = IRQ_ports[state->irq];

	if (info->next_port)

		info->next_port->prev_port = info;

	IRQ_ports[state->irq] = info;



	if (info->tty) clear_bit(TTY_IO_ERROR, &info->tty->flags);



	info->xmit.head = info->xmit.tail = 0;

include/linux/serialP.h

+0 −2
Original line number Diff line number Diff line
@@ -56,8 +56,6 @@ struct async_struct { 
	wait_queue_head_t	open_wait;

	wait_queue_head_t	close_wait;

	wait_queue_head_t	delta_msr_wait;

	struct async_struct	*next_port; /* For the linked list */

	struct async_struct	*prev_port;

};



#endif /* _LINUX_SERIAL_H */

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