Hi,
On Sun, Jun 28, 2020 at 02:23:12PM +1000, Finn Thain wrote:
The interrupt handler should be excluded when accessing the autopoll_devs
variable.
I am quite baffled by this patch. Other than adding an unnecessary lock /
unlock sequence, accessing a variable (which is derived from another
variable) from inside or outside a lock does not make a difference.
If autopoll_devs = devs & 0xfffe is 0 inside the lock, it will just
as much be 0 outside the lock, and vice versa.
Can you explain this in some more detail ? Not that is matters much since
the change already made it into mainline, but I would like to understand
what if anything I am missing here.
Thanks,
Guenter
Fixes: d95fd5fce88f0 ("m68k: Mac II ADB fixes") # v5.0+
Tested-by: Stan Johnson <userm57@xxxxxxxxx>
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
---
drivers/macintosh/via-macii.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/macintosh/via-macii.c b/drivers/macintosh/via-macii.c
index ac824d7b2dcfc..6aa903529570d 100644
--- a/drivers/macintosh/via-macii.c
+++ b/drivers/macintosh/via-macii.c
@@ -270,15 +270,12 @@ static int macii_autopoll(int devs)
unsigned long flags;
int err = 0;
+ local_irq_save(flags);
+
/* bit 1 == device 1, and so on. */
autopoll_devs = devs & 0xFFFE;
- if (!autopoll_devs)
- return 0;
-
- local_irq_save(flags);
-
- if (current_req == NULL) {
+ if (autopoll_devs && !current_req) {
/* Send a Talk Reg 0. The controller will repeatedly transmit
* this as long as it is idle.
*/
