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Commit 5552c28f authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
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[PATCH] Fix locking error in esp 



Noted by Al Viro.

Also remove unused tmp_buf

Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 30379440

drivers/char/esp.c

+2 −20
Original line number Diff line number Diff line
@@ -150,17 +150,6 @@ static void rs_wait_until_sent(struct tty_struct *, int); 
/* Standard COM flags (except for COM4, because of the 8514 problem) */

#define STD_COM_FLAGS (ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST)



/*

 * tmp_buf is used as a temporary buffer by serial_write.  We need to

 * lock it in case the memcpy_fromfs blocks while swapping in a page,

 * and some other program tries to do a serial write at the same time.

 * Since the lock will only come under contention when the system is

 * swapping and available memory is low, it makes sense to share one

 * buffer across all the serial ports, since it significantly saves

 * memory if large numbers of serial ports are open.

 */

static unsigned char *tmp_buf;



static inline int serial_paranoia_check(struct esp_struct *info,

					char *name, const char *routine)

{
@@ -1267,7 +1256,7 @@ static int rs_write(struct tty_struct * tty, 
	if (serial_paranoia_check(info, tty->name, "rs_write"))

		return 0;



	if (!tty || !info->xmit_buf || !tmp_buf)

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

		return 0;

	    

	while (1) {
@@ -2291,11 +2280,7 @@ static int esp_open(struct tty_struct *tty, struct file * filp) 
	tty->driver_data = info;

	info->tty = tty;



	if (!tmp_buf) {

		tmp_buf = (unsigned char *) get_zeroed_page(GFP_KERNEL);

		if (!tmp_buf)

			return -ENOMEM;

	}

	spin_unlock_irqrestore(&info->lock, flags);

	

	/*

	 * Start up serial port
@@ -2602,9 +2587,6 @@ static void __exit espserial_exit(void) 
		free_pages((unsigned long)dma_buffer,

			get_order(DMA_BUFFER_SZ));



	if (tmp_buf)

		free_page((unsigned long)tmp_buf);



	while (free_pio_buf) {

		pio_buf = free_pio_buf->next;

		kfree(free_pio_buf);