X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fchar%2Fsynclink.c;h=ede688a4e141ad71834fb90930d83b7466751caa;hb=987b0145d94eecf292d8b301228356f44611ab7c;hp=fee2aca3f6a5c7eb77c8c07135489644e5ec8ab2;hpb=f7ed79d23a47594e7834d66a8f14449796d4f3e6;p=linux-2.6.git

diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index fee2aca3f..ede688a4e 100644
--- a/drivers/char/synclink.c
+++ b/drivers/char/synclink.c
@@ -941,6 +941,17 @@ static void* mgsl_get_text_ptr(void)
 	return mgsl_get_text_ptr;
 }
 
+/*
+ * tmp_buf is used as a temporary buffer by mgsl_write.  We need to
+ * lock it in case the COPY_FROM_USER 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 ioports, since it significantly saves
+ * memory if large numbers of serial ports are open.
+ */
+static unsigned char *tmp_buf;
+
 static inline int mgsl_paranoia_check(struct mgsl_struct *info,
 					char *name, const char *routine)
 {
@@ -2139,7 +2150,7 @@ static int mgsl_write(struct tty_struct * tty,
 	if (mgsl_paranoia_check(info, tty->name, "mgsl_write"))
 		goto cleanup;
 
-	if (!tty || !info->xmit_buf)
+	if (!tty || !info->xmit_buf || !tmp_buf)
 		goto cleanup;
 
 	if ( info->params.mode == MGSL_MODE_HDLC ||
@@ -3427,6 +3438,7 @@ static int mgsl_open(struct tty_struct *tty, struct file * filp)
 {
 	struct mgsl_struct	*info;
 	int 			retval, line;
+	unsigned long		page;
 	unsigned long flags;
 
 	/* verify range of specified line number */	
@@ -3460,6 +3472,18 @@ static int mgsl_open(struct tty_struct *tty, struct file * filp)
 		goto cleanup;
 	}
 	
+	if (!tmp_buf) {
+		page = get_zeroed_page(GFP_KERNEL);
+		if (!page) {
+			retval = -ENOMEM;
+			goto cleanup;
+		}
+		if (tmp_buf)
+			free_page(page);
+		else
+			tmp_buf = (unsigned char *) page;
+	}
+	
 	info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
 	spin_lock_irqsave(&info->netlock, flags);
@@ -4478,6 +4502,11 @@ static void synclink_cleanup(void)
 		kfree(tmp);
 	}
 	
+	if (tmp_buf) {
+		free_page((unsigned long) tmp_buf);
+		tmp_buf = NULL;
+	}
+	
 	if (pci_registered)
 		pci_unregister_driver(&synclink_pci_driver);
 }
@@ -5996,7 +6025,7 @@ static void usc_set_async_mode( struct mgsl_struct *info )
 	 * <15..8>	?		RxFIFO IRQ Request Level
 	 *
 	 * Note: For async mode the receive FIFO level must be set
-	 * to 0 to avoid the situation where the FIFO contains fewer bytes
+	 * to 0 to aviod the situation where the FIFO contains fewer bytes
 	 * than the trigger level and no more data is expected.
 	 *
 	 * <7>		0		Exited Hunt IA (Interrupt Arm)
@@ -7741,7 +7770,7 @@ static int hdlcdev_attach(struct net_device *dev, unsigned short encoding,
 	}
 
 	info->params.encoding = new_encoding;
-	info->params.crc_type = new_crctype;
+	info->params.crc_type = new_crctype;;
 
 	/* if network interface up, reprogram hardware */
 	if (info->netcount)