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Subject[PATCH 4/4] m68k/mac: Add mutual exclusion for IOP interrupt polling
Date
The IOP interrupt handler iop_ism_irq() is used by the adb-iop
driver to poll for ADB request completion. Unfortunately, it is not
re-entrant. Fix the race condition by adding an iop_ism_irq_poll()
function with suitable mutual exclusion.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
arch/m68k/include/asm/mac_iop.h | 1 +
arch/m68k/mac/iop.c | 9 +++++++++
drivers/macintosh/adb-iop.c | 4 +---
3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/m68k/include/asm/mac_iop.h b/arch/m68k/include/asm/mac_iop.h
index 42566fd052bc..d2a08e004e2c 100644
--- a/arch/m68k/include/asm/mac_iop.h
+++ b/arch/m68k/include/asm/mac_iop.h
@@ -158,6 +158,7 @@ extern void iop_complete_message(struct iop_msg *);
extern void iop_upload_code(uint, __u8 *, uint, __u16);
extern void iop_download_code(uint, __u8 *, uint, __u16);
extern __u8 *iop_compare_code(uint, __u8 *, uint, __u16);
+extern void iop_ism_irq_poll(uint);

extern void iop_register_interrupts(void);

diff --git a/arch/m68k/mac/iop.c b/arch/m68k/mac/iop.c
index a2ea52db7d18..9bfa17015768 100644
--- a/arch/m68k/mac/iop.c
+++ b/arch/m68k/mac/iop.c
@@ -598,3 +598,12 @@ irqreturn_t iop_ism_irq(int irq, void *dev_id)
}
return IRQ_HANDLED;
}
+
+void iop_ism_irq_poll(uint iop_num)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ iop_ism_irq(0, (void *)iop_num);
+ local_irq_restore(flags);
+}
diff --git a/drivers/macintosh/adb-iop.c b/drivers/macintosh/adb-iop.c
index f5f4da3d0b67..4b0ad3995497 100644
--- a/drivers/macintosh/adb-iop.c
+++ b/drivers/macintosh/adb-iop.c
@@ -29,8 +29,6 @@

/*#define DEBUG_ADB_IOP*/

-extern void iop_ism_irq(int, void *);
-
static struct adb_request *current_req;
static struct adb_request *last_req;
#if 0
@@ -265,7 +263,7 @@ int adb_iop_autopoll(int devs)
void adb_iop_poll(void)
{
if (adb_iop_state == idle) adb_iop_start();
- iop_ism_irq(0, (void *) ADB_IOP);
+ iop_ism_irq_poll(ADB_IOP);
}

int adb_iop_reset_bus(void)
--
2.13.6
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