Alan Stern wrote:
> On Fri, 17 Dec 2004, Wakko Warner wrote:
> > I'd love to do this with my 2.4 boxen. Any pointers on what to remove?
>
> On Fri, 17 Dec 2004, Matthew Dharm wrote:
>
> > Actually, the 2.4 SCSI core doesn't support hot-unplug very well. So it's
> > more difficult than just changing usb-storage.
>
> That may be. But usb-storage seems to manage okay during rmmod, so maybe
> it won't be so bad.
>
> Wakko, what you need to change is all in the drivers/usb/storage/usb.c
> source file.
I've done this and it appears to be working just fine for me. Stupidly I
tested it on a machine I didn't want to crash, however, it worked.
I made the modifications as a configurable item.
Here's the patch. I consider it experiemental since I don't have that much
knowledge of the usb-storage module.
diff -ru 2.4.26-orig/Documentation/Configure.help
2.4.26-mod/Documentation/Configure.help
--- 2.4.26-orig/Documentation/Configure.help Wed Apr 28 08:03:04 2004
+++ 2.4.26-mod/Documentation/Configure.help Fri Jan 14 11:04:53 2005
@@ -15756,6 +15770,12 @@
CONFIG_USB_STORAGE_DEBUG
Say Y here in order to have the USB Mass Storage code generate
verbose debugging messages.
+
+Do not remember unplugged devices
+CONFIG_USB_STORAGE_REMOVE_UNPLUGGED
+ Say Y here to remove USB mass storage devices when they are unplugged.
+
+ If unsure, say N.
ISD-200 USB/ATA Bridge support
CONFIG_USB_STORAGE_ISD200
diff -ru 2.4.26-orig/drivers/usb/Config.in 2.4.26-mod/drivers/usb/Config.in
--- 2.4.26-orig/drivers/usb/Config.in Fri Apr 9 08:14:50 2004
+++ 2.4.26-mod/drivers/usb/Config.in Fri Jan 14 11:01:47 2005
@@ -34,6 +34,7 @@
fi
dep_tristate ' USB Mass Storage support' CONFIG_USB_STORAGE $CONFIG_USB
$CONFIG_SCSI
dep_mbool ' USB Mass Storage verbose debug' CONFIG_USB_STORAGE_DEBUG
$CONFIG_USB_STORAGE
+ dep_mbool ' Do not remember unplugged devices'
CONFIG_USB_STORAGE_REMOVE_UNPLUGGED $CONFIG_USB_STORAGE
dep_mbool ' Datafab MDCFE-B Compact Flash Reader support'
CONFIG_USB_STORAGE_DATAFAB $CONFIG_USB_STORAGE $CONFIG_EXPERIMENTAL
dep_mbool ' Freecom USB/ATAPI Bridge support'
CONFIG_USB_STORAGE_FREECOM $CONFIG_USB_STORAGE
dep_mbool ' ISD-200 USB/ATA Bridge support' CONFIG_USB_STORAGE_ISD200
$CONFIG_USB_STORAGE $CONFIG_IDE
diff -ru 2.4.26-orig/drivers/usb/storage/usb.c
2.4.26-mod/drivers/usb/storage/usb.c
--- 2.4.26-orig/drivers/usb/storage/usb.c Fri Apr 9 08:14:51 2004
+++ 2.4.26-mod/drivers/usb/storage/usb.c Fri Jan 14 11:01:02 2005
@@ -700,6 +700,7 @@
* We're looking for a device with a matching GUID that isn't
* already on the system
*/
+#ifndef CONFIG_USB_STORAGE_REMOVE_UNPLUGGED
ss = us_list;
while ((ss != NULL) &&
((ss->pusb_dev) || !GUID_EQUAL(guid, ss->guid)))
@@ -749,6 +750,7 @@
up(&(ss->dev_semaphore));
} else {
+#endif
/* New device -- allocate memory and initialize */
US_DEBUGP("New GUID " GUID_FORMAT "\n", GUID_ARGS(guid));
@@ -1034,7 +1036,9 @@
/* release the data structure lock */
up(&us_list_semaphore);
+#ifndef CONFIG_USB_STORAGE_REMOVE_UNPLUGGED
}
+#endif
printk(KERN_DEBUG
"WARNING: USB Mass Storage data integrity not assured\n");
@@ -1049,6 +1053,8 @@
static void storage_disconnect(struct usb_device *dev, void *ptr)
{
struct us_data *ss = ptr;
+ struct us_data *next;
+ struct us_data *last;
int result;
US_DEBUGP("storage_disconnect() called\n");
@@ -1080,9 +1086,50 @@
usb_free_urb(ss->current_urb);
ss->current_urb = NULL;
+#ifndef CONFIG_USB_STORAGE_REMOVE_UNPLUGGED
/* mark the device as gone */
usb_dec_dev_use(ss->pusb_dev);
ss->pusb_dev = NULL;
+#else
+ /* Deregister the scsi host for this device */
+ scsi_unregister_module(MODULE_SCSI_HA, &(ss->htmplt));
+
+ /* Search for this structure and remove it from the list
+ * since I don't understand the workings of this module, I feel
+ * it best to remove it here and free the memory used by it */
+ last = NULL;
+ next = us_list;
+ while ((next != NULL) &&
+ ((next->pusb_dev) || !GUID_EQUAL(ss->guid, next->guid))) {
+ last = next;
+ next = next->next;
+ }
+
+ /* If found, remove the link to it and free this one */
+ if (next != NULL) {
+ if (last == NULL)
+ us_list = next->next;
+ else
+ last->next = next->next;
+
+ /* If there's extra data in the us_data structure then
+ * free that first */
+ if (next->extra) {
+ /* call the destructor routine, if it exists */
+ if (next->extra_destructor) {
+ US_DEBUGP("-- calling extra_destructor()\n");
+ next->extra_destructor(next->extra);
+ }
+
+ /* destroy the extra data */
+ US_DEBUGP("-- freeing the data structure\n");
+ kfree(next->extra);
+ }
+
+ /* free the structure itself */
+ kfree (next);
+ }
+#endif
/* unlock access to the device data structure */
up(&(ss->dev_semaphore));
@@ -1127,10 +1174,12 @@
* the structures because of possible races with the /proc
* interface
*/
+#ifndef CONFIG_USB_STORAGE_REMOVE_UNPLUGGED
for (next = us_list; next; next = next->next) {
US_DEBUGP("-- calling scsi_unregister_module()\n");
scsi_unregister_module(MODULE_SCSI_HA, &(next->htmplt));
}
+#endif
/* While there are still structures, free them. Note that we are
* now race-free, since these structures can no longer be accessed
--
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