Here's a patch against 2.5.38 that does the following:
- adds a call to /sbin/hotplug to the driver core
- removes the call to /sbin/hotplug from the pci and usb cores
- adds a callback to the struct bus_type for the driver core to
use to set up bus specific /sbin/hotplug arguments.
One nice side effect of this patch, is that all iterfaces for a USB
device generate a call to /sbin/hotplug, so complex devices should now
be properly recognized by userspace much easier.
I've successfully tested this with both PCI Hotplug systems, and USB
devices. There is still a bug remaining that causes an oops when a USB
pci controller is unloaded from the system that I am still tracking
down. After I find this problem, and if there are no complaints, I'll
send it on to Linus.
Comments appreciated.
thanks,
greg k-h
diff -Nru a/drivers/base/Makefile b/drivers/base/Makefile
--- a/drivers/base/Makefile Wed Sep 25 14:22:28 2002
+++ b/drivers/base/Makefile Wed Sep 25 14:22:28 2002
@@ -5,6 +5,10 @@
obj-y += fs/
+ifeq ($(CONFIG_HOTPLUG),y)
+ obj-y += hotplug.o
+endif
+
export-objs := core.o power.o sys.o bus.o driver.o \
class.o intf.o
diff -Nru a/drivers/base/base.h b/drivers/base/base.h
--- a/drivers/base/base.h Wed Sep 25 14:22:28 2002
+++ b/drivers/base/base.h Wed Sep 25 14:22:28 2002
@@ -50,3 +50,13 @@
extern int driver_attach(struct device_driver * drv);
extern void driver_detach(struct device_driver * drv);
+
+#ifdef CONFIG_HOTPLUG
+extern int dev_hotplug(struct device *dev, const char *action);
+#else
+static inline int dev_hotplug(struct device *dev, const char *action)
+{
+ return 0;
+}
+#endif
+
diff -Nru a/drivers/base/core.c b/drivers/base/core.c
--- a/drivers/base/core.c Wed Sep 25 14:22:28 2002
+++ b/drivers/base/core.c Wed Sep 25 14:22:28 2002
@@ -198,6 +198,9 @@
if (platform_notify)
platform_notify(dev);
+ /* notify userspace of device entry */
+ dev_hotplug(dev, "add");
+
register_done:
if (error) {
spin_lock(&device_lock);
@@ -255,6 +258,9 @@
device_detach(dev);
bus_remove_device(dev);
+
+ /* notify userspace that this device just disappeared */
+ dev_hotplug (dev, "remove");
/* remove the driverfs directory */
device_remove_dir(dev);
diff -Nru a/drivers/base/hotplug.c b/drivers/base/hotplug.c
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/drivers/base/hotplug.c Wed Sep 25 14:22:28 2002
@@ -0,0 +1,114 @@
+/*
+ * drivers/base/hotplug.c - hotplug call code
+ *
+ * Copyright (c) 2002 Greg Kroah-Hartman <greg@kroah.com>
+ * 2002 IBM Corp.
+ */
+
+#define DEBUG 0
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/kmod.h>
+#include <linux/interrupt.h>
+#include "base.h"
+
+/*
+ * hotplugging invokes what /proc/sys/kernel/hotplug says (normally
+ * /sbin/hotplug) when devices get added or removed.
+ *
+ * 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.
+ */
+#define BUFFER_SIZE 1024 /* should be enough memory for the env */
+#define NUM_ENVP 32 /* number of env pointers */
+int dev_hotplug (struct device *dev, const char *action)
+{
+ char *argv [3], **envp, *buffer, *scratch;
+ int retval;
+ int i = 0;
+
+ pr_debug ("%s\n", __FUNCTION__);
+ if (!dev)
+ return -ENODEV;
+
+ if (!dev->bus || !dev->bus->hotplug)
+ return -ENODEV;
+
+ if (!hotplug_path [0])
+ return -ENODEV;
+
+ if (in_interrupt ()) {
+ pr_debug ("%s - in_interrupt, not allowed!", __FUNCTION__);
+ return -EIO;
+ }
+
+ if (!current->fs->root) {
+ /* don't try to do anything unless we have a root partition */
+ pr_debug ("%s - %s -- no FS yet\n", __FUNCTION__, action);
+ return -EIO;
+ }
+
+ envp = (char **) kmalloc (NUM_ENVP * sizeof (char *), GFP_KERNEL);
+ if (!envp)
+ return -ENOMEM;
+
+ buffer = kmalloc (BUFFER_SIZE, GFP_KERNEL);
+ if (!buffer) {
+ kfree (envp);
+ return -ENOMEM;
+ }
+
+ /* only one standardized param to hotplug command: the bus name */
+ argv [0] = hotplug_path;
+ argv [1] = dev->bus->name;
+ argv [2] = 0;
+
+ /* minimal command environment */
+ envp [i++] = "HOME=/";
+ envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+
+#ifdef DEBUG
+ /* hint that policy agent should enter no-stdout debug mode */
+ envp [i++] = "DEBUG=kernel";
+#endif
+
+ scratch = buffer;
+ /* action: add, remove */
+ envp [i++] = scratch;
+ scratch += sprintf (scratch, "ACTION=%s", action) + 1;
+
+ /* have the bus specific function set up the rest of the environment */
+ retval = dev->bus->hotplug (dev, &envp[i], NUM_ENVP - i,
+ scratch, BUFFER_SIZE - (scratch - buffer));
+ if (retval) {
+ pr_debug ("%s - hotplug() returned %d\n", __FUNCTION__, retval);
+ goto exit;
+ }
+
+ pr_debug ("%s: %s %s %s %s %s %s\n", __FUNCTION__, argv [0], argv[1],
+ action, envp[0], envp[1], envp[2]);
+ retval = call_usermodehelper (argv [0], argv, envp);
+ if (retval)
+ pr_debug ("%s - call_usermodehelper returned %d\n",
+ __FUNCTION__, retval);
+
+exit:
+ kfree (buffer);
+ kfree (envp);
+ return retval;
+}
diff -Nru a/drivers/pci/hotplug.c b/drivers/pci/hotplug.c
--- a/drivers/pci/hotplug.c Wed Sep 25 14:22:28 2002
+++ b/drivers/pci/hotplug.c Wed Sep 25 14:22:28 2002
@@ -1,52 +1,42 @@
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/kmod.h> /* for hotplug_path */
+#include "pci.h"
-#ifndef FALSE
-#define FALSE (0)
-#define TRUE (!FALSE)
-#endif
#ifdef CONFIG_HOTPLUG
-static void run_sbin_hotplug(struct pci_dev *pdev, int insert)
+int pci_hotplug (struct device *dev, char **envp, int num_envp,
+ char *buffer, int buffer_size)
{
- int i;
- char *argv[3], *envp[8];
- char id[20], sub_id[24], bus_id[24], class_id[20];
-
- if (!hotplug_path[0])
- return;
-
- sprintf(class_id, "PCI_CLASS=%04X", pdev->class);
- sprintf(id, "PCI_ID=%04X:%04X", pdev->vendor, pdev->device);
- sprintf(sub_id, "PCI_SUBSYS_ID=%04X:%04X", pdev->subsystem_vendor, pdev->subsystem_device);
- sprintf(bus_id, "PCI_SLOT_NAME=%s", pdev->slot_name);
-
- i = 0;
- argv[i++] = hotplug_path;
- argv[i++] = "pci";
- argv[i] = 0;
-
- i = 0;
- /* minimal command environment */
- envp[i++] = "HOME=/";
- envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
-
- /* other stuff we want to pass to /sbin/hotplug */
- envp[i++] = class_id;
- envp[i++] = id;
- envp[i++] = sub_id;
- envp[i++] = bus_id;
- if (insert)
- envp[i++] = "ACTION=add";
- else
- envp[i++] = "ACTION=remove";
+ struct pci_dev *pdev = to_pci_dev(dev);
+ char *scratch;
+ int i = 0;
+
+ scratch = buffer;
+
+ /* stuff we want to pass to /sbin/hotplug */
+ envp[i++] = scratch;
+ scratch += sprintf (scratch, "PCI_CLASS=%04X", pdev->class) + 1;
+
+ envp[i++] = scratch;
+ scratch += sprintf (scratch, "PCI_ID=%04X:%04X",
+ pdev->vendor, pdev->device) + 1;
+ envp[i++] = scratch;
+ scratch += sprintf (scratch, "PCI_SUBSYS_ID=%04X:%04X",
+ pdev->subsystem_vendor, pdev->subsystem_device) + 1;
+ envp[i++] = scratch;
+ scratch += sprintf (scratch, "PCI_SLOT_NAME=%s", pdev->slot_name) + 1;
envp[i] = 0;
- call_usermodehelper (argv [0], argv, envp);
+ /* check to see if we went over buffer? */
+ return 0;
}
#else
-static void run_sbin_hotplug(struct pci_dev *pdev, int insert) { }
+int pci_hotplug (struct device *dev, char **envp, int num_envp,
+ char *buffer, int buffer_size)
+{
+ return -ENODEV;
+}
#endif
/**
@@ -66,8 +56,6 @@
#ifdef CONFIG_PROC_FS
pci_proc_attach_device(dev);
#endif
- /* notify userspace of new hotplug device */
- run_sbin_hotplug(dev, TRUE);
}
static void
@@ -99,8 +87,6 @@
#ifdef CONFIG_PROC_FS
pci_proc_detach_device(dev);
#endif
- /* notify userspace of hotplug device removal */
- run_sbin_hotplug(dev, FALSE);
}
#ifdef CONFIG_HOTPLUG
diff -Nru a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
--- a/drivers/pci/pci-driver.c Wed Sep 25 14:22:28 2002
+++ b/drivers/pci/pci-driver.c Wed Sep 25 14:22:28 2002
@@ -6,6 +6,7 @@
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/init.h>
+#include "pci.h"
/*
* Registration of PCI drivers and handling of hot-pluggable devices.
@@ -199,8 +200,9 @@
}
struct bus_type pci_bus_type = {
- name: "pci",
- match: pci_bus_match,
+ name: "pci",
+ match: pci_bus_match,
+ hotplug: pci_hotplug,
};
static int __init pci_driver_init(void)
diff -Nru a/drivers/pci/pci.h b/drivers/pci/pci.h
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/drivers/pci/pci.h Wed Sep 25 14:22:28 2002
@@ -0,0 +1,5 @@
+/* Functions internal to the PCI core code */
+
+extern int pci_hotplug (struct device *dev, char **envp, int num_envp,
+ char *buffer, int buffer_size);
+
diff -Nru a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
--- a/drivers/usb/core/usb.c Wed Sep 25 14:22:28 2002
+++ b/drivers/usb/core/usb.c Wed Sep 25 14:22:28 2002
@@ -505,57 +505,41 @@
* cases, we know no other thread can recycle our address, since we must
* already have been serialized enough to prevent that.
*/
-static void call_policy (char *verb, struct usb_device *dev)
+static int usb_hotplug (struct device *dev, char **envp, int num_envp,
+ char *buffer, int buffer_size)
{
- char *argv [3], **envp, *buf, *scratch;
- int i = 0, value;
+ struct usb_interface *intf;
+ struct usb_device *usb_dev;
+ char *scratch;
+ 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 ("%s", __FUNCTION__);
+
+ if (!dev)
+ return -ENODEV;
+
+ /* check for generic driver, we do not call do hotplug calls for it */
+ if (dev->driver == &usb_generic_driver)
+ return -ENODEV;
+
+ intf = to_usb_interface(dev);
+ if (!intf)
+ return -ENODEV;
+
+ usb_dev = interface_to_usbdev (intf);
+ if (!usb_dev)
+ return -ENODEV;
+
+ if (usb_dev->devnum < 0) {
dbg ("device already deleted ??");
- return;
+ return -ENODEV;
}
- if (!(envp = (char **) kmalloc (20 * sizeof (char *), GFP_KERNEL))) {
- dbg ("enomem");
- return;
- }
- if (!(buf = kmalloc (256, GFP_KERNEL))) {
- kfree (envp);
- dbg ("enomem2");
- return;
+ if (!usb_dev->bus) {
+ dbg ("bus already removed?");
+ return -ENODEV;
}
- /* only one standardized param to hotplug command: type */
- argv [0] = hotplug_path;
- argv [1] = "usb";
- argv [2] = 0;
-
- /* minimal command environment */
- envp [i++] = "HOME=/";
- envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
-
-#ifdef DEBUG
- /* hint that policy agent should enter no-stdout debug mode */
- envp [i++] = "DEBUG=kernel";
-#endif
- /* extensible set of named bus-specific parameters,
- * supporting multiple driver selection algorithms.
- */
- scratch = buf;
-
- /* action: add, remove */
- envp [i++] = scratch;
- scratch += sprintf (scratch, "ACTION=%s", verb) + 1;
+ scratch = buffer;
#ifdef CONFIG_USB_DEVICEFS
/* If this is available, userspace programs can directly read
@@ -565,26 +549,35 @@
* FIXME reduce hardwired intelligence here
*/
envp [i++] = "DEVFS=/proc/bus/usb";
+ if (i >= num_envp)
+ return -ENOMEM;
+
envp [i++] = scratch;
scratch += sprintf (scratch, "DEVICE=/proc/bus/usb/%03d/%03d",
- dev->bus->busnum, dev->devnum) + 1;
+ usb_dev->bus->busnum, usb_dev->devnum) + 1;
+ if (i >= num_envp)
+ return -ENOMEM;
#endif
-
/* per-device configuration hacks are common */
envp [i++] = scratch;
scratch += sprintf (scratch, "PRODUCT=%x/%x/%x",
- dev->descriptor.idVendor,
- dev->descriptor.idProduct,
- dev->descriptor.bcdDevice) + 1;
+ usb_dev->descriptor.idVendor,
+ usb_dev->descriptor.idProduct,
+ usb_dev->descriptor.bcdDevice) + 1;
+ if (i >= num_envp)
+ return -ENOMEM;
/* class-based driver binding models */
envp [i++] = scratch;
scratch += sprintf (scratch, "TYPE=%d/%d/%d",
- dev->descriptor.bDeviceClass,
- dev->descriptor.bDeviceSubClass,
- dev->descriptor.bDeviceProtocol) + 1;
- if (dev->descriptor.bDeviceClass == 0) {
- int alt = dev->actconfig->interface [0].act_altsetting;
+ usb_dev->descriptor.bDeviceClass,
+ usb_dev->descriptor.bDeviceSubClass,
+ usb_dev->descriptor.bDeviceProtocol) + 1;
+ if (i >= num_envp)
+ return -ENOMEM;
+
+ if (usb_dev->descriptor.bDeviceClass == 0) {
+ int alt = intf->act_altsetting;
/* a simple/common case: one config, one interface, one driver
* with current altsetting being a reasonable setting.
@@ -593,30 +586,27 @@
*/
envp [i++] = scratch;
scratch += sprintf (scratch, "INTERFACE=%d/%d/%d",
- dev->actconfig->interface [0].altsetting [alt].bInterfaceClass,
- dev->actconfig->interface [0].altsetting [alt].bInterfaceSubClass,
- dev->actconfig->interface [0].altsetting [alt].bInterfaceProtocol)
+ intf->altsetting[alt].bInterfaceClass,
+ intf->altsetting[alt].bInterfaceSubClass,
+ intf->altsetting[alt].bInterfaceProtocol)
+ 1;
- /* INTERFACE-0, INTERFACE-1, ... ? */
+ if (i >= num_envp)
+ return -ENOMEM;
+
}
envp [i++] = 0;
- /* assert: (scratch - buf) < sizeof buf */
+ /* assert: (scratch - buffer) < buffer_size */
- /* 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);
- kfree (buf);
- kfree (envp);
- if (value != 0)
- dbg ("kusbd policy returned 0x%x", value);
+ return 0;
}
#else
-static inline void
-call_policy (char *verb, struct usb_device *dev)
-{ }
+static int usb_hotplug (struct device *dev, char **envp,
+ char *buffer, int buffer_size)
+{
+ return -ENODEV;
+}
#endif /* CONFIG_HOTPLUG */
@@ -889,9 +879,6 @@
put_device(&dev->dev);
}
- /* Let policy agent unload modules etc */
- call_policy ("remove", dev);
-
/* Decrement the reference count, it'll auto free everything when */
/* it hits 0 which could very well be now */
usb_put_dev(dev);
@@ -1169,9 +1156,6 @@
/* add a /proc/bus/usb entry */
usbfs_add_device(dev);
- /* userspace may load modules and/or configure further */
- call_policy ("add", dev);
-
return 0;
}
@@ -1434,6 +1418,7 @@
struct bus_type usb_bus_type = {
.name = "usb",
.match = usb_device_match,
+ .hotplug = usb_hotplug,
};
/*
diff -Nru a/include/linux/device.h b/include/linux/device.h
--- a/include/linux/device.h Wed Sep 25 14:22:28 2002
+++ b/include/linux/device.h Wed Sep 25 14:22:28 2002
@@ -67,6 +67,8 @@
int (*match)(struct device * dev, struct device_driver * drv);
struct device * (*add) (struct device * parent, char * bus_id);
+ int (*hotplug) (struct device *dev, char **envp,
+ int num_envp, char *buffer, int buffer_size);
};
-
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