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Commit 0a245982 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: serial2002: factor (*poll) busy wait out of tty_read() 



Factor the (*poll) busy wait code out of tty_read() so the indent
level can be reduced and tty_read() is a bit cleaner.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 32ef0e3e

drivers/staging/comedi/drivers/serial2002.c

+28 −25
Original line number Diff line number Diff line
@@ -102,6 +102,33 @@ static int __tty_readb(struct file *f, unsigned char *buf) 
	return f->f_op->read(f, p, 1, &f->f_pos);

}



static void tty_read_poll_wait(struct file *f, int timeout)

{

	struct poll_wqueues table;

	struct timeval start, now;



	do_gettimeofday(&start);

	poll_initwait(&table);

	while (1) {

		long elapsed;

		int mask;



		mask = f->f_op->poll(f, &table.pt);

		if (mask & (POLLRDNORM | POLLRDBAND | POLLIN |

			    POLLHUP | POLLERR)) {

			break;

		}

		do_gettimeofday(&now);

		elapsed = (1000000 * (now.tv_sec - start.tv_sec) +

			  now.tv_usec - start.tv_usec);

		if (elapsed > timeout)

			break;

		set_current_state(TASK_INTERRUPTIBLE);

		schedule_timeout(((timeout - elapsed) * HZ) / 10000);

	}

	poll_freewait(&table);

}



#if 0

/*

 * On 2.6.26.3 this occaisonally gave me page faults, worked around by
@@ -132,31 +159,7 @@ static int tty_read(struct file *f, int timeout) 
		oldfs = get_fs();

		set_fs(KERNEL_DS);

		if (f->f_op->poll) {

			struct poll_wqueues table;

			struct timeval start, now;



			do_gettimeofday(&start);

			poll_initwait(&table);

			while (1) {

				long elapsed;

				int mask;



				mask = f->f_op->poll(f, &table.pt);

				if (mask & (POLLRDNORM | POLLRDBAND | POLLIN |

					    POLLHUP | POLLERR)) {

					break;

				}

				do_gettimeofday(&now);

				elapsed =

				    (1000000 * (now.tv_sec - start.tv_sec) +

				     now.tv_usec - start.tv_usec);

				if (elapsed > timeout)

					break;

				set_current_state(TASK_INTERRUPTIBLE);

				schedule_timeout(((timeout -

						   elapsed) * HZ) / 10000);

			}

			poll_freewait(&table);

			tty_read_poll_wait(f, timeout);



			if (__tty_readb(f, &ch) == 1)

				result = ch;