[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>
diff --git a/drivers/char/esp.c b/drivers/char/esp.c
index 57539d8..09dc4b0 100644
--- a/drivers/char/esp.c
+++ b/drivers/char/esp.c
@@ -150,17 +150,6 @@
/* 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 @@
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 @@
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 @@
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);