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Message-id: <20461285551864014911@wsc.cz>
Date: Sun, 20 May 2007 23:25:11 +0200 (CEST)
From: Jiri Slaby <jirislaby@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/3] Char: isicom, cleanup locking
isicom, cleanup locking
don't spin processor when not needed (use sleep instead of delay). Don't
release the lock when needed in next iteration -- this actually fixes a
bug -- missing braces
Signed-off-by: Jiri Slaby <jirislaby@...il.com>
---
commit af05316f4ba7503ae531f3afdb5264c10e3b8e2c
tree 2fac39ab09e16f20329fc785beeb7607b6ed8bc9
parent a9dbc0b98956d548b1aee3f55b3799a12946ace4
author Jiri Slaby <jirislaby@...il.com> Sun, 20 May 2007 21:32:42 +0200
committer Jiri Slaby <jirislaby@...il.com> Sun, 20 May 2007 21:32:42 +0200
drivers/char/isicom.c | 65 ++++++++++++++++++++-----------------------------
1 files changed, 27 insertions(+), 38 deletions(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 761f777..b133b92 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -243,17 +243,18 @@ static inline int WaitTillCardIsFree(u16 base)
static int lock_card(struct isi_board *card)
{
- char retries;
unsigned long base = card->base;
+ unsigned int retries, a;
- for (retries = 0; retries < 100; retries++) {
+ for (retries = 0; retries < 10; retries++) {
spin_lock_irqsave(&card->card_lock, card->flags);
- if (inw(base + 0xe) & 0x1) {
- return 1;
- } else {
- spin_unlock_irqrestore(&card->card_lock, card->flags);
- udelay(1000); /* 1ms */
+ for (a = 0; a < 10; a++) {
+ if (inw(base + 0xe) & 0x1)
+ return 1;
+ udelay(10);
}
+ spin_unlock_irqrestore(&card->card_lock, card->flags);
+ msleep(10);
}
printk(KERN_WARNING "ISICOM: Failed to lock Card (0x%lx)\n",
card->base);
@@ -261,23 +262,6 @@ static int lock_card(struct isi_board *card)
return 0; /* Failed to acquire the card! */
}
-static int lock_card_at_interrupt(struct isi_board *card)
-{
- unsigned char retries;
- unsigned long base = card->base;
-
- for (retries = 0; retries < 200; retries++) {
- spin_lock_irqsave(&card->card_lock, card->flags);
-
- if (inw(base + 0xe) & 0x1)
- return 1;
- else
- spin_unlock_irqrestore(&card->card_lock, card->flags);
- }
- /* Failing in interrupt is an acceptable event */
- return 0; /* Failed to acquire the card! */
-}
-
static void unlock_card(struct isi_board *card)
{
spin_unlock_irqrestore(&card->card_lock, card->flags);
@@ -415,6 +399,8 @@ static inline int __isicom_paranoia_check(struct isi_port const *port,
static void isicom_tx(unsigned long _data)
{
+ unsigned long flags;
+ unsigned int retries;
short count = (BOARD_COUNT-1), card, base;
short txcount, wrd, residue, word_count, cnt;
struct isi_port *port;
@@ -435,32 +421,34 @@ static void isicom_tx(unsigned long _data)
count = isi_card[card].port_count;
port = isi_card[card].ports;
base = isi_card[card].base;
+
+ spin_lock_irqsave(&isi_card[card].card_lock, flags);
+ for (retries = 0; retries < 100; retries++) {
+ if (inw(base + 0xe) & 0x1)
+ break;
+ udelay(2);
+ }
+ if (retries >= 100)
+ goto unlock;
+
for (;count > 0;count--, port++) {
- if (!lock_card_at_interrupt(&isi_card[card]))
- continue;
/* port not active or tx disabled to force flow control */
if (!(port->flags & ASYNC_INITIALIZED) ||
!(port->status & ISI_TXOK))
- unlock_card(&isi_card[card]);
continue;
tty = port->tty;
-
- if (tty == NULL) {
- unlock_card(&isi_card[card]);
+ if (tty == NULL)
continue;
- }
txcount = min_t(short, TX_SIZE, port->xmit_cnt);
- if (txcount <= 0 || tty->stopped || tty->hw_stopped) {
- unlock_card(&isi_card[card]);
+ if (txcount <= 0 || tty->stopped || tty->hw_stopped)
continue;
- }
- if (!(inw(base + 0x02) & (1 << port->channel))) {
- unlock_card(&isi_card[card]);
+
+ if (!(inw(base + 0x02) & (1 << port->channel)))
continue;
- }
+
pr_dbg("txing %d bytes, port%d.\n", txcount,
port->channel + 1);
outw((port->channel << isi_card[card].shift_count) | txcount,
@@ -508,9 +496,10 @@ static void isicom_tx(unsigned long _data)
port->status &= ~ISI_TXOK;
if (port->xmit_cnt <= WAKEUP_CHARS)
tty_wakeup(tty);
- unlock_card(&isi_card[card]);
}
+unlock:
+ spin_unlock_irqrestore(&isi_card[card].card_lock, flags);
/* schedule another tx for hopefully in about 10ms */
sched_again:
if (!re_schedule) {
-
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