cyclades: push down tty_port_tty_get

Now, the tty is not needed at all places in the ISR. So we can just
request in on demand when really needed.

This cleans TX and RX paths a bit as the indentation level can be
dropped by two now when we also invert the char_count if condition.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/cyclades.c

@@ -917,7 +917,7 @@ cyz_issue_cmd(struct cyclades_card *cinfo,
 	return 0;
 }				/* cyz_issue_cmd */
 
-static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
+static void cyz_handle_rx(struct cyclades_port *info)
 {
 	struct BUF_CTRL __iomem *buf_ctrl = info->u.cyz.buf_ctrl;
 	struct cyclades_card *cinfo = info->card;
@@ -940,7 +940,9 @@ static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
 	else
 		char_count = rx_put - rx_get + rx_bufsize;
 
-	if (char_count) {
+	if (!char_count)
+		return;
+
 #ifdef CY_ENABLE_MONITORING
 	info->mon.int_count++;
 	info->mon.char_count += char_count;
@@ -948,12 +950,7 @@ static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
 		info->mon.char_max = char_count;
 	info->mon.char_last = char_count;
 #endif
-		if (tty == NULL) {
-			/* flush received characters */
-			new_rx_get = (new_rx_get + char_count) &
-					(rx_bufsize - 1);
-			info->rflush_count++;
-		} else {
+
 #ifdef BLOCKMOVE
 	/* we'd like to use memcpy(t, f, n) and memset(s, c, count)
 	   for performance, but because of buffer boundaries, there
@@ -1004,16 +1001,16 @@ static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
 #endif
 	info->idle_stats.recv_idle = jiffies;
 	tty_schedule_flip(&info->port);
-		}
+
 	/* Update rx_get */
 	cy_writel(&buf_ctrl->rx_get, new_rx_get);
-	}
 }
 
-static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
+static void cyz_handle_tx(struct cyclades_port *info)
 {
 	struct BUF_CTRL __iomem *buf_ctrl = info->u.cyz.buf_ctrl;
 	struct cyclades_card *cinfo = info->card;
+	struct tty_struct *tty;
 	u8 data;
 	unsigned int char_count;
 #ifdef BLOCKMOVE
@@ -1033,8 +1030,10 @@ static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
 	else
 		char_count = tx_get - tx_put - 1;
 
-	if (char_count) {
+	if (!char_count)
+		return;
 		
+	tty = tty_port_tty_get(&info->port);
 	if (tty == NULL)
 		goto ztxdone;
 
@@ -1054,8 +1053,7 @@ static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
 				min_t(unsigned int, info->xmit_cnt,
 					char_count))))) {
 
-			memcpy_toio((char *)(cinfo->base_addr + tx_bufaddr +
-					tx_put),
+		memcpy_toio((char *)(cinfo->base_addr + tx_bufaddr + tx_put),
 				&info->port.xmit_buf[info->xmit_tail],
 				small_count);
 
@@ -1080,16 +1078,15 @@ static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
 	}
 #endif
 	tty_wakeup(tty);
+	tty_kref_put(tty);
 ztxdone:
 	/* Update tx_put */
 	cy_writel(&buf_ctrl->tx_put, tx_put);
-	}
 }
 
 static void cyz_handle_cmd(struct cyclades_card *cinfo)
 {
 	struct BOARD_CTRL __iomem *board_ctrl = cinfo->board_ctrl;
-	struct tty_struct *tty;
 	struct cyclades_port *info;
 	__u32 channel, param, fw_ver;
 	__u8 cmd;
@@ -1102,9 +1099,6 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
 		special_count = 0;
 		delta_count = 0;
 		info = &cinfo->ports[channel];
-		tty = tty_port_tty_get(&info->port);
-		if (tty == NULL)
-			continue;
 
 		switch (cmd) {
 		case C_CM_PR_ERROR:
@@ -1130,8 +1124,14 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
 					readl(&info->u.cyz.ch_ctrl->rs_status);
 				if (dcd & C_RS_DCD)
 					wake_up_interruptible(&info->port.open_wait);
-				else
+				else {
+					struct tty_struct *tty;
+					tty = tty_port_tty_get(&info->port);
+					if (tty) {
 						tty_hangup(tty);
+						tty_kref_put(tty);
+					}
+				}
 			}
 			break;
 		case C_CM_MCTS:
@@ -1160,7 +1160,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
 			printk(KERN_DEBUG "cyz_interrupt: rcvd intr, card %d, "
 					"port %ld\n", info->card, channel);
 #endif
-			cyz_handle_rx(info, tty);
+			cyz_handle_rx(info);
 			break;
 		case C_CM_TXBEMPTY:
 		case C_CM_TXLOWWM:
@@ -1170,7 +1170,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
 			printk(KERN_DEBUG "cyz_interrupt: xmit intr, card %d, "
 					"port %ld\n", info->card, channel);
 #endif
-			cyz_handle_tx(info, tty);
+			cyz_handle_tx(info);
 			break;
 #endif				/* CONFIG_CYZ_INTR */
 		case C_CM_FATAL:
@@ -1183,7 +1183,6 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
 			wake_up_interruptible(&info->port.delta_msr_wait);
 		if (special_count)
 			tty_schedule_flip(&info->port);
-		tty_kref_put(tty);
 	}
 }
 
@@ -1249,17 +1248,11 @@ static void cyz_poll(unsigned long arg)
 		cyz_handle_cmd(cinfo);
 
 		for (port = 0; port < cinfo->nports; port++) {
-			struct tty_struct *tty;
-
 			info = &cinfo->ports[port];
-			tty = tty_port_tty_get(&info->port);
-			/* OK to pass NULL to the handle functions below.
-			   They need to drop the data in that case. */
 
 			if (!info->throttle)
-				cyz_handle_rx(info, tty);
-			cyz_handle_tx(info, tty);
-			tty_kref_put(tty);
+				cyz_handle_rx(info);
+			cyz_handle_tx(info);
 		}
 		/* poll every 'cyz_polling_cycle' period */
 		expires = jiffies + cyz_polling_cycle;