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[PATCH] Fix locking error in esp 

Noted by Al Viro.

Also remove unused tmp_buf

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Alan Cox 2006-02-14 17:50:54 +00:00 committed by Linus Torvalds
parent 3037944009
commit 5552c28f69
1 changed files with 2 additions and 20 deletions
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22
drivers/char/esp.c
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@ -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);