x86/platform/amd: replace down_timeout() with down_interruptible()

Currently hsmp_send_message() uses down_timeout() with a 100ms timeout
to take the semaphore. However __hsmp_send_message(), the content of the
critical section, has a sleep in it. On systems with significantly
delayed scheduling behaviour this may take over 100ms.

Convert this method to down_interruptible(). Leave the error handling
the same as the documentation currently is not specific about what error
is returned.

Previous behaviour: a caller who competes with another caller stuck in
the critical section due to scheduler delays would receive -ETIME.

New behaviour: a caller who competes with another caller stuck in the
critical section due to scheduler delays will complete successfully.

Reviewed-by: Suma Hegde <[email protected]>
Tested-by: Suma Hegde <[email protected]>
Signed-off-by: Jake Hillion <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Ilpo Järvinen <[email protected]>

Author: JakeHillion

drivers/platform/x86/amd/hsmp/hsmp.c

@@ -214,13 +214,7 @@ int hsmp_send_message(struct hsmp_message *msg)
 		return -ENODEV;
 	sock = &hsmp_pdev.sock[msg->sock_ind];
 
-	/*
-	 * The time taken by smu operation to complete is between
-	 * 10us to 1ms. Sometime it may take more time.
-	 * In SMP system timeout of 100 millisecs should
-	 * be enough for the previous thread to finish the operation
-	 */
-	ret = down_timeout(&sock->hsmp_sem, msecs_to_jiffies(HSMP_MSG_TIMEOUT));
+	ret = down_interruptible(&sock->hsmp_sem);
 	if (ret < 0)
 		return ret;