From 8d046e26898d4a44b3028f97278653bad8a77f20 Mon Sep 17 00:00:00 2001
From: Augustin Cavalier <waddlesplash@gmail.com>
Date: Mon, 20 Sep 2021 11:40:46 -0400
Subject: [PATCH] USB: Split WaitForUnbusy from Object::PutUSBID.

In a few instances, we need to not wait for objects to become unbusy
during ID puts because we expect they still will be, e.g. in the case
of Control pipes with submitted transfers that are still running. There,
we need to put the ID, cancel transfers, and only then wait for the
object to become unbusy.

Technically, this is a functional change, but at least in practice
it will have little real-world effect, for two reasons:

 1. The DefaultPipe's Busy flag is basically never updated (the Device's
    busy flag is generally used instead), so it will virtually never be
    "busy".

 2. Most devices have no Control endpoints besides that default one.

Change-Id: I32ff4094effeac9ec74546c9643ea2025418e1c1
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4491
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
---
 src/add-ons/kernel/bus_managers/usb/Device.cpp |  3 ++-
 src/add-ons/kernel/bus_managers/usb/Object.cpp | 18 ++++++++++++------
 src/add-ons/kernel/bus_managers/usb/Pipe.cpp   |  3 ++-
 .../kernel/bus_managers/usb/usb_private.h      |  3 ++-
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/add-ons/kernel/bus_managers/usb/Device.cpp b/src/add-ons/kernel/bus_managers/usb/Device.cpp
index e80ecd0e47..5e4bc842b6 100644
--- a/src/add-ons/kernel/bus_managers/usb/Device.cpp
+++ b/src/add-ons/kernel/bus_managers/usb/Device.cpp
@@ -329,8 +329,9 @@ Device::~Device()
 	// Cancel transfers on the default pipe and put its USBID to prevent
 	// further transfers from being queued.
 	if (fDefaultPipe != NULL) {
-		fDefaultPipe->PutUSBID();
+		fDefaultPipe->PutUSBID(false);
 		fDefaultPipe->CancelQueuedTransfers(true);
+		fDefaultPipe->WaitForUnbusy();
 	}
 
 	// Destroy open endpoints. Do not send a device request to unconfigure
diff --git a/src/add-ons/kernel/bus_managers/usb/Object.cpp b/src/add-ons/kernel/bus_managers/usb/Object.cpp
index d2a3f5966b..595dbc03de 100644
--- a/src/add-ons/kernel/bus_managers/usb/Object.cpp
+++ b/src/add-ons/kernel/bus_managers/usb/Object.cpp
@@ -36,20 +36,26 @@ Object::~Object()
 
 
 void
-Object::PutUSBID()
+Object::PutUSBID(bool waitForUnbusy)
 {
-	if (fUSBID == UINT32_MAX)
-		return;
+	if (fUSBID != UINT32_MAX) {
+		fStack->PutUSBID(this);
+		fUSBID = UINT32_MAX;
+	}
 
-	fStack->PutUSBID(this);
+	if (waitForUnbusy)
+		WaitForUnbusy();
+}
 
+
+void
+Object::WaitForUnbusy()
+{
 	int32 retries = 20;
 	while (atomic_get(&fBusy) != 0 && retries--)
 		snooze(100);
 	if (retries <= 0)
 		panic("USB object did not become unbusy!");
-
-	fUSBID = UINT32_MAX;
 }
 
 
diff --git a/src/add-ons/kernel/bus_managers/usb/Pipe.cpp b/src/add-ons/kernel/bus_managers/usb/Pipe.cpp
index 106b8857ec..58249e7a01 100644
--- a/src/add-ons/kernel/bus_managers/usb/Pipe.cpp
+++ b/src/add-ons/kernel/bus_managers/usb/Pipe.cpp
@@ -338,8 +338,9 @@ ControlPipe::ControlPipe(Object *parent)
 ControlPipe::~ControlPipe()
 {
 	// We do this here in case a submitted request is still running.
-	PutUSBID();
+	PutUSBID(false);
 	ControlPipe::CancelQueuedTransfers(true);
+	WaitForUnbusy();
 
 	if (fNotifySem >= 0)
 		delete_sem(fNotifySem);
diff --git a/src/add-ons/kernel/bus_managers/usb/usb_private.h b/src/add-ons/kernel/bus_managers/usb/usb_private.h
index a5bd1ba43d..a5bcd77fa4 100644
--- a/src/add-ons/kernel/bus_managers/usb/usb_private.h
+++ b/src/add-ons/kernel/bus_managers/usb/usb_private.h
@@ -278,7 +278,8 @@ virtual	status_t						ClearFeature(uint16 selector);
 virtual	status_t						GetStatus(uint16 *status);
 
 protected:
-		void							PutUSBID();
+		void							PutUSBID(bool waitForUnbusy = true);
+		void							WaitForUnbusy();
 
 private:
 		Object *						fParent;