[PATCH] PATCH: usb-storage: use kthread API
This patch is originally from Alan Stern (as569). It has been rediffed
against a current tree.
This patch converts usb-storage to use the kthread API for creating its
control and scanning threads. The new code doesn't use kthread_stop
because the threads need (or will need in the future) to exit
asynchronously.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index c1a9026..3847ebe 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -54,6 +54,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
+#include <linux/kthread.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
@@ -310,22 +311,7 @@
struct us_data *us = (struct us_data *)__us;
struct Scsi_Host *host = us_to_host(us);
- lock_kernel();
-
- /*
- * This thread doesn't need any user-level access,
- * so get rid of all our resources.
- */
- daemonize("usb-storage");
current->flags |= PF_NOFREEZE;
- unlock_kernel();
-
- /* acquire a reference to the host, so it won't be deallocated
- * until we're ready to exit */
- scsi_host_get(host);
-
- /* signal that we've started the thread */
- complete(&(us->notify));
for(;;) {
US_DEBUGP("*** thread sleeping.\n");
@@ -768,6 +754,7 @@
static int usb_stor_acquire_resources(struct us_data *us)
{
int p;
+ struct task_struct *th;
us->current_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!us->current_urb) {
@@ -784,17 +771,19 @@
}
/* Start up our control thread */
- p = kernel_thread(usb_stor_control_thread, us, CLONE_VM);
- if (p < 0) {
+ th = kthread_create(usb_stor_control_thread, us, "usb-storage");
+ if (IS_ERR(th)) {
printk(KERN_WARNING USB_STORAGE
"Unable to start control thread\n");
- return p;
+ return PTR_ERR(th);
}
- us->pid = p;
- atomic_inc(&total_threads);
- /* Wait for the thread to start */
- wait_for_completion(&(us->notify));
+ /* Take a reference to the host for the control thread and
+ * count it among all the threads we have launched. Then
+ * start it up. */
+ scsi_host_get(us_to_host(us));
+ atomic_inc(&total_threads);
+ wake_up_process(th);
return 0;
}
@@ -890,21 +879,6 @@
{
struct us_data *us = (struct us_data *)__us;
- /*
- * This thread doesn't need any user-level access,
- * so get rid of all our resources.
- */
- lock_kernel();
- daemonize("usb-stor-scan");
- unlock_kernel();
-
- /* Acquire a reference to the host, so it won't be deallocated
- * until we're ready to exit */
- scsi_host_get(us_to_host(us));
-
- /* Signal that we've started the thread */
- complete(&(us->notify));
-
printk(KERN_DEBUG
"usb-storage: device found at %d\n", us->pusb_dev->devnum);
@@ -949,6 +923,7 @@
struct us_data *us;
const int id_index = id - storage_usb_ids;
int result;
+ struct task_struct *th;
US_DEBUGP("USB Mass Storage device detected\n");
@@ -1029,17 +1004,21 @@
}
/* Start up the thread for delayed SCSI-device scanning */
- result = kernel_thread(usb_stor_scan_thread, us, CLONE_VM);
- if (result < 0) {
+ th = kthread_create(usb_stor_scan_thread, us, "usb-stor-scan");
+ if (IS_ERR(th)) {
printk(KERN_WARNING USB_STORAGE
"Unable to start the device-scanning thread\n");
quiesce_and_remove_host(us);
+ result = PTR_ERR(th);
goto BadDevice;
}
- atomic_inc(&total_threads);
- /* Wait for the thread to start */
- wait_for_completion(&(us->notify));
+ /* Take a reference to the host for the scanning thread and
+ * count it among all the threads we have launched. Then
+ * start it up. */
+ scsi_host_get(us_to_host(us));
+ atomic_inc(&total_threads);
+ wake_up_process(th);
return 0;