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Subject[PATCH 5/7] macintosh/via-macii: Simplify locking
Date
Modifying the request queue or changing the current state requires
mutual exclusion. Use local_irq_disable() consistently for this
rather than disabling the ADB interrupt. This simplifies the locking
scheme and brings via-macii into line with the other ADB drivers.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
drivers/macintosh/via-macii.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/macintosh/via-macii.c b/drivers/macintosh/via-macii.c
index 7e0e32fa7eb2..6ed9ac91aca1 100644
--- a/drivers/macintosh/via-macii.c
+++ b/drivers/macintosh/via-macii.c
@@ -216,22 +216,23 @@ static void macii_queue_poll(void)
static int macii_send_request(struct adb_request *req, int sync)
{
int err;
- unsigned long flags;

- local_irq_save(flags);
err = macii_write(req);
- local_irq_restore(flags);
+ if (err)
+ return err;

- if (!err && sync)
+ if (sync)
while (!req->complete)
macii_poll();

- return err;
+ return 0;
}

/* Send an ADB request (append to request queue) */
static int macii_write(struct adb_request *req)
{
+ unsigned long flags;
+
if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
req->complete = 1;
return -EINVAL;
@@ -242,6 +243,8 @@ static int macii_write(struct adb_request *req)
req->complete = 0;
req->reply_len = 0;

+ local_irq_save(flags);
+
if (current_req != NULL) {
last_req->next = req;
last_req = req;
@@ -250,6 +253,9 @@ static int macii_write(struct adb_request *req)
last_req = req;
if (macii_state == idle) macii_start();
}
+
+ local_irq_restore(flags);
+
return 0;
}

@@ -293,9 +299,7 @@ static inline int need_autopoll(void) {
/* Prod the chip without interrupts */
static void macii_poll(void)
{
- disable_irq(IRQ_MAC_ADB);
macii_interrupt(0, NULL);
- enable_irq(IRQ_MAC_ADB);
}

/* Reset the bus */
@@ -358,13 +362,18 @@ static irqreturn_t macii_interrupt(int irq, void *arg)
{
int x;
struct adb_request *req;
+ unsigned long flags;
+
+ local_irq_save(flags);

if (!arg) {
/* Clear the SR IRQ flag when polling. */
if (via[IFR] & SR_INT)
via[IFR] = SR_INT;
- else
+ else {
+ local_irq_restore(flags);
return IRQ_NONE;
+ }
}

last_status = status;
@@ -512,5 +521,6 @@ static irqreturn_t macii_interrupt(int irq, void *arg)
break;
}

+ local_irq_restore(flags);
return IRQ_HANDLED;
}
--
2.16.4
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