[PATCH] Char: isicom, eliminate spinlock recursion
Many spinlock recursion was in the isicom driver. Eliminate it.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 5a747e6..01084ab 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -230,6 +230,20 @@
* it wants to talk.
*/
+static inline int WaitTillCardIsFree(u16 base)
+{
+ unsigned int count = 0;
+ unsigned int a = in_atomic(); /* do we run under spinlock? */
+
+ while (!(inw(base + 0xe) & 0x1) && count++ < 100)
+ if (a)
+ mdelay(1);
+ else
+ msleep(1);
+
+ return !(inw(base + 0xe) & 0x1);
+}
+
static int lock_card(struct isi_board *card)
{
char retries;
@@ -276,69 +290,71 @@
* ISI Card specific ops ...
*/
+/* card->lock HAS to be held */
static void raise_dtr(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0504, base);
InterruptTheCard(base);
port->status |= ISI_DTR;
- unlock_card(card);
}
+/* card->lock HAS to be held */
static inline void drop_dtr(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0404, base);
InterruptTheCard(base);
port->status &= ~ISI_DTR;
- unlock_card(card);
}
+/* card->lock HAS to be held */
static inline void raise_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0a04, base);
InterruptTheCard(base);
port->status |= ISI_RTS;
- unlock_card(card);
}
+
+/* card->lock HAS to be held */
static inline void drop_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0804, base);
InterruptTheCard(base);
port->status &= ~ISI_RTS;
- unlock_card(card);
}
+/* card->lock MUST NOT be held */
static inline void raise_dtr_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
@@ -355,35 +371,20 @@
unlock_card(card);
}
+/* card->lock HAS to be held */
static void drop_dtr_rts(struct isi_port *port)
{
struct isi_board *card = port->card;
unsigned long base = card->base;
u16 channel = port->channel;
- if (!lock_card(card))
+ if (WaitTillCardIsFree(base))
return;
outw(0x8000 | (channel << card->shift_count) | 0x02, base);
outw(0x0c04, base);
InterruptTheCard(base);
port->status &= ~(ISI_RTS | ISI_DTR);
- unlock_card(card);
-}
-
-static inline void kill_queue(struct isi_port *port, short queue)
-{
- struct isi_board *card = port->card;
- unsigned long base = card->base;
- u16 channel = port->channel;
-
- if (!lock_card(card))
- return;
-
- outw(0x8000 | (channel << card->shift_count) | 0x02, base);
- outw((queue << 8) | 0x06, base);
- InterruptTheCard(base);
- unlock_card(card);
}
/*
@@ -744,7 +745,7 @@
else
raise_dtr(port);
- if (lock_card(card)) {
+ if (WaitTillCardIsFree(base) == 0) {
outw(0x8000 | (channel << shift_count) |0x03, base);
outw(linuxb_to_isib[baud] << 8 | 0x03, base);
channel_setup = 0;
@@ -772,7 +773,6 @@
}
outw(channel_setup, base);
InterruptTheCard(base);
- unlock_card(card);
}
if (C_CLOCAL(tty))
port->flags &= ~ASYNC_CHECK_CD;
@@ -791,12 +791,11 @@
if (I_IXOFF(tty))
flow_ctrl |= ISICOM_INITIATE_XONXOFF;
- if (lock_card(card)) {
+ if (WaitTillCardIsFree(base) == 0) {
outw(0x8000 | (channel << shift_count) |0x04, base);
outw(flow_ctrl << 8 | 0x05, base);
outw((STOP_CHAR(tty)) << 8 | (START_CHAR(tty)), base);
InterruptTheCard(base);
- unlock_card(card);
}
/* rx enabled -> enable port for rx on the card */
@@ -821,10 +820,9 @@
}
port = bp->ports;
bp->status |= BOARD_ACTIVE;
- spin_unlock_irqrestore(&bp->card_lock, flags);
for (channel = 0; channel < bp->port_count; channel++, port++)
drop_dtr_rts(port);
- return;
+ spin_unlock_irqrestore(&bp->card_lock, flags);
}
static int isicom_setup_port(struct isi_port *port)
@@ -857,7 +855,12 @@
port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
/* discard any residual data */
- kill_queue(port, ISICOM_KILLTX | ISICOM_KILLRX);
+ if (WaitTillCardIsFree(card->base) == 0) {
+ outw(0x8000 | (port->channel << card->shift_count) | 0x02,
+ card->base);
+ outw(((ISICOM_KILLTX | ISICOM_KILLRX) << 8) | 0x06, card->base);
+ InterruptTheCard(card->base);
+ }
isicom_config_port(port);
port->flags |= ASYNC_INITIALIZED;
@@ -983,28 +986,22 @@
static inline void isicom_shutdown_board(struct isi_board *bp)
{
- unsigned long flags;
-
- spin_lock_irqsave(&bp->card_lock, flags);
if (bp->status & BOARD_ACTIVE) {
bp->status &= ~BOARD_ACTIVE;
}
- spin_unlock_irqrestore(&bp->card_lock, flags);
}
+/* card->lock HAS to be held */
static void isicom_shutdown_port(struct isi_port *port)
{
struct isi_board *card = port->card;
struct tty_struct *tty;
- unsigned long flags;
tty = port->tty;
- spin_lock_irqsave(&card->card_lock, flags);
- if (!(port->flags & ASYNC_INITIALIZED)) {
- spin_unlock_irqrestore(&card->card_lock, flags);
+ if (!(port->flags & ASYNC_INITIALIZED))
return;
- }
+
if (port->xmit_buf) {
free_page((unsigned long) port->xmit_buf);
port->xmit_buf = NULL;
@@ -1012,7 +1009,6 @@
port->flags &= ~ASYNC_INITIALIZED;
/* 3rd October 2000 : Vinayak P Risbud */
port->tty = NULL;
- spin_unlock_irqrestore(&card->card_lock, flags);
/*Fix done by Anil .S on 30-04-2001
remote login through isi port has dtr toggle problem
@@ -1258,10 +1254,12 @@
unsigned int set, unsigned int clear)
{
struct isi_port *port = tty->driver_data;
+ unsigned long flags;
if (isicom_paranoia_check(port, tty->name, "isicom_ioctl"))
return -ENODEV;
+ spin_lock_irqsave(&port->card->card_lock, flags);
if (set & TIOCM_RTS)
raise_rts(port);
if (set & TIOCM_DTR)
@@ -1271,6 +1269,7 @@
drop_rts(port);
if (clear & TIOCM_DTR)
drop_dtr(port);
+ spin_unlock_irqrestore(&port->card->card_lock, flags);
return 0;
}
@@ -1303,7 +1302,10 @@
(newinfo.flags & ASYNC_FLAGS));
}
if (reconfig_port) {
+ unsigned long flags;
+ spin_lock_irqsave(&port->card->card_lock, flags);
isicom_config_port(port);
+ spin_unlock_irqrestore(&port->card->card_lock, flags);
}
return 0;
}
@@ -1384,6 +1386,7 @@
struct ktermios *old_termios)
{
struct isi_port *port = tty->driver_data;
+ unsigned long flags;
if (isicom_paranoia_check(port, tty->name, "isicom_set_termios"))
return;
@@ -1392,7 +1395,9 @@
tty->termios->c_iflag == old_termios->c_iflag)
return;
+ spin_lock_irqsave(&port->card->card_lock, flags);
isicom_config_port(port);
+ spin_unlock_irqrestore(&port->card->card_lock, flags);
if ((old_termios->c_cflag & CRTSCTS) &&
!(tty->termios->c_cflag & CRTSCTS)) {
@@ -1469,11 +1474,15 @@
static void isicom_hangup(struct tty_struct *tty)
{
struct isi_port *port = tty->driver_data;
+ unsigned long flags;
if (isicom_paranoia_check(port, tty->name, "isicom_hangup"))
return;
+ spin_lock_irqsave(&port->card->card_lock, flags);
isicom_shutdown_port(port);
+ spin_unlock_irqrestore(&port->card->card_lock, flags);
+
port->count = 0;
port->flags &= ~ASYNC_NORMAL_ACTIVE;
port->tty = NULL;
@@ -1578,16 +1587,6 @@
return retval;
}
-static inline int WaitTillCardIsFree(u16 base)
-{
- unsigned long count = 0;
-
- while (!(inw(base + 0xe) & 0x1) && count++ < 100)
- msleep(5);
-
- return !(inw(base + 0xe) & 0x1);
-}
-
static int __devinit load_firmware(struct pci_dev *pdev,
const unsigned int index, const unsigned int signature)
{
