From: Jesper Juhl <jesper.juhl@gmail.com>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Scott H Kilau <Scott_Kilau@digi.com>,
Wendy Xiong <wendyx@us.ltcfwd.linux.ibm.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Andrew Morton <akpm@osdl.org>,
Jesper Juhl <jesper.juhl@gmail.com>
Subject: [PATCH] Decrease number of pointer derefs in jsm_tty.c
Date: Thu, 8 Dec 2005 23:36:45 +0100 [thread overview]
Message-ID: <200512082336.46198.jesper.juhl@gmail.com> (raw)
Hi,
Here's a small patch to decrease the number of pointer derefs in
drivers/serial/jsm/jsm_tty.c
Benefits of the patch:
- Fewer pointer dereferences should make the code slightly faster.
- Size of generated code is smaller
- Improved readability
Please consider applying.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
---
drivers/serial/jsm/jsm_tty.c | 29 +++++++++++++++++------------
1 files changed, 17 insertions(+), 12 deletions(-)
orig:
text data bss dec hex filename
7937 80 0 8017 1f51 drivers/serial/jsm/jsm_tty.o
patched:
text data bss dec hex filename
7874 80 0 7954 1f12 drivers/serial/jsm/jsm_tty.o
--- linux-2.6.15-rc5-git1-orig/drivers/serial/jsm/jsm_tty.c 2005-10-28 02:02:08.000000000 +0200
+++ linux-2.6.15-rc5-git1/drivers/serial/jsm/jsm_tty.c 2005-12-08 22:45:48.000000000 +0100
@@ -140,12 +140,14 @@ static void jsm_tty_send_xchar(struct ua
{
unsigned long lock_flags;
struct jsm_channel *channel = (struct jsm_channel *)port;
+ struct termios *termios;
spin_lock_irqsave(&port->lock, lock_flags);
- if (ch == port->info->tty->termios->c_cc[VSTART])
+ termios = port->info->tty->termios;
+ if (ch == termios->c_cc[VSTART])
channel->ch_bd->bd_ops->send_start_character(channel);
- if (ch == port->info->tty->termios->c_cc[VSTOP])
+ if (ch == termios->c_cc[VSTOP])
channel->ch_bd->bd_ops->send_stop_character(channel);
spin_unlock_irqrestore(&port->lock, lock_flags);
}
@@ -176,6 +178,7 @@ static int jsm_tty_open(struct uart_port
struct jsm_board *brd;
int rc = 0;
struct jsm_channel *channel = (struct jsm_channel *)port;
+ struct termios *termios;
/* Get board pointer from our array of majors we have allocated */
brd = channel->ch_bd;
@@ -237,12 +240,13 @@ static int jsm_tty_open(struct uart_port
channel->ch_cached_lsr = 0;
channel->ch_stops_sent = 0;
- channel->ch_c_cflag = port->info->tty->termios->c_cflag;
- channel->ch_c_iflag = port->info->tty->termios->c_iflag;
- channel->ch_c_oflag = port->info->tty->termios->c_oflag;
- channel->ch_c_lflag = port->info->tty->termios->c_lflag;
- channel->ch_startc = port->info->tty->termios->c_cc[VSTART];
- channel->ch_stopc = port->info->tty->termios->c_cc[VSTOP];
+ termios = port->info->tty->termios;
+ channel->ch_c_cflag = termios->c_cflag;
+ channel->ch_c_iflag = termios->c_iflag;
+ channel->ch_c_oflag = termios->c_oflag;
+ channel->ch_c_lflag = termios->c_lflag;
+ channel->ch_startc = termios->c_cc[VSTART];
+ channel->ch_stopc = termios->c_cc[VSTOP];
/* Tell UART to init itself */
brd->bd_ops->uart_init(channel);
@@ -863,6 +867,7 @@ static void jsm_carrier(struct jsm_chann
void jsm_check_queue_flow_control(struct jsm_channel *ch)
{
+ struct board_ops *bd_ops = ch->ch_bd->bd_ops;
int qleft = 0;
/* Store how much space we have left in the queue */
@@ -888,7 +893,7 @@ void jsm_check_queue_flow_control(struct
/* HWFLOW */
if (ch->ch_c_cflag & CRTSCTS) {
if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
- ch->ch_bd->bd_ops->disable_receiver(ch);
+ bd_ops->disable_receiver(ch);
ch->ch_flags |= (CH_RECEIVER_OFF);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Internal queue hit hilevel mark (%d)! Turning off interrupts.\n",
@@ -898,7 +903,7 @@ void jsm_check_queue_flow_control(struct
/* SWFLOW */
else if (ch->ch_c_iflag & IXOFF) {
if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
- ch->ch_bd->bd_ops->send_stop_character(ch);
+ bd_ops->send_stop_character(ch);
ch->ch_stops_sent++;
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Sending stop char! Times sent: %x\n", ch->ch_stops_sent);
@@ -925,7 +930,7 @@ void jsm_check_queue_flow_control(struct
/* HWFLOW */
if (ch->ch_c_cflag & CRTSCTS) {
if (ch->ch_flags & CH_RECEIVER_OFF) {
- ch->ch_bd->bd_ops->enable_receiver(ch);
+ bd_ops->enable_receiver(ch);
ch->ch_flags &= ~(CH_RECEIVER_OFF);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Internal queue hit lowlevel mark (%d)! Turning on interrupts.\n",
@@ -935,7 +940,7 @@ void jsm_check_queue_flow_control(struct
/* SWFLOW */
else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
ch->ch_stops_sent = 0;
- ch->ch_bd->bd_ops->send_start_character(ch);
+ bd_ops->send_start_character(ch);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "Sending start char!\n");
}
}
reply other threads:[~2005-12-08 22:36 UTC|newest]
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