This updates the doc and code to match what's been
true since 2.4.0 (!) and keventd, removing some error
checks that are now handled lower down as well as
making a few messages less confusing ("kusbd" etc).
Please merge to Linus' latest. I think it should
also work against the 2.4 tree (with different "-p")
and if so, it's worth applying there too.
- Dave
--- ./drivers/usb-dist/core/usb.c Mon Jun 3 10:18:29 2002
+++ ./drivers/usb/core/usb.c Thu Jun 27 10:08:21 2002
@@ -754,39 +754,24 @@
/*
* USB hotplugging invokes what /proc/sys/kernel/hotplug says
* (normally /sbin/hotplug) when USB devices get added or removed.
+ * May not be called in_interrupt().
*
* This invokes a user mode policy agent, typically helping to load driver
* or other modules, configure the device, and more. Drivers can provide
* a MODULE_DEVICE_TABLE to help with module loading subtasks.
*
- * Some synchronization is important: removes can't start processing
- * before the add-device processing completes, and vice versa. That keeps
- * a stack of USB-related identifiers stable while they're in use. If we
- * know that agents won't complete after they return (such as by forking
- * a process that completes later), it's enough to just waitpid() for the
- * agent -- as is currently done.
- *
- * The reason: we know we're called either from khubd (the typical case)
- * or from root hub initialization (init, kapmd, modprobe, etc). In both
- * cases, we know no other thread can recycle our address, since we must
- * already have been serialized enough to prevent that.
+ * keventd task sequencing ensures that removes can't start processing
+ * before the add-device processing completes, and vice versa ... but only
+ * so far as user mode reporting goes. khubd can process disconnects
+ * for devices before the hotplug connect event gets reported, since there
+ * is no synchronization once keventd is given its job. This basically
+ * means usb hotplug agents need to verify any usbfs names they see.
*/
static void call_policy (char *verb, struct usb_device *dev)
{
char *argv [3], **envp, *buf, *scratch;
- int i = 0, value;
+ int i = 0;
- if (!hotplug_path [0])
- return;
- if (in_interrupt ()) {
- dbg ("In_interrupt");
- return;
- }
- if (!current->fs->root) {
- /* statically linked USB is initted rather early */
- dbg ("call_policy %s, num %d -- no FS yet", verb, dev->devnum);
- return;
- }
if (dev->devnum < 0) {
dbg ("device already deleted ??");
return;
@@ -854,7 +839,7 @@
/* a simple/common case: one config, one interface, one driver
* with current altsetting being a reasonable setting.
- * everything needs a smart agent and usbfs; or can rely on
+ * otherwise needs a smart agent and usbfs; or can rely on
* device-specific binding policies.
*/
envp [i++] = scratch;
@@ -870,12 +855,10 @@
/* NOTE: user mode daemons can call the agents too */
- dbg ("kusbd: %s %s %d", argv [0], verb, dev->devnum);
- value = call_usermodehelper (argv [0], argv, envp);
+ dbg ("%s %s %d", argv [0], verb, dev->devnum);
+ (void) call_usermodehelper (argv [0], argv, envp);
kfree (buf);
kfree (envp);
- if (value != 0)
- dbg ("kusbd policy returned 0x%x", value);
}
#else
