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Subject[PATCH] macintosh/adb: Convert to the kthread API
Date
From: Eric W. Biederman <ebiederm@xmission.com> - unquoted

This patch modifies the startup of kadbprobe to use
kthread_run instead of scheduling a work event which
later calls kernel_thread and in the thread calls
daemonize and blocks signals. kthread_run is simpler
and more maintainable.

The variable pid_t adb_probe_task_pid is replaced by
a struct task_struct variable named adb_probe_task.
Which works equally well with for testing if the current
process is the adb_probe thread, does not get confused
in the presence of a pid namespace and is easier to
compare against current as it is the same type.

The result is code that is slightly simpler and easier
to maintain.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
drivers/macintosh/adb.c | 32 +++++++-------------------------
1 files changed, 7 insertions(+), 25 deletions(-)
diff --git a/drivers/macintosh/adb.c b/drivers/macintosh/adb.c
index adfea3c..09c5261 100644
--- a/drivers/macintosh/adb.c
+++ b/drivers/macintosh/adb.c
@@ -35,6 +35,7 @@
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/device.h>
+#include <linux/kthread.h>

#include <asm/uaccess.h>
#include <asm/semaphore.h>
@@ -82,7 +83,7 @@ struct adb_driver *adb_controller;
BLOCKING_NOTIFIER_HEAD(adb_client_list);
static int adb_got_sleep;
static int adb_inited;
-static pid_t adb_probe_task_pid;
+static struct task_struct *adb_probe_task;
static DECLARE_MUTEX(adb_probe_mutex);
static struct completion adb_probe_task_comp;
static int sleepy_trackpad;
@@ -137,8 +138,7 @@ static void printADBreply(struct adb_request *req)

static __inline__ void adb_wait_ms(unsigned int ms)
{
- if (current->pid && adb_probe_task_pid &&
- adb_probe_task_pid == current->pid)
+ if (adb_probe_task == current)
msleep(ms);
else
mdelay(ms);
@@ -245,35 +245,19 @@ static int adb_scan_bus(void)
* This kernel task handles ADB probing. It dies once probing is
* completed.
*/
-static int
-adb_probe_task(void *x)
+static int adb_probe(void *x)
{
- sigset_t blocked;
-
- strcpy(current->comm, "kadbprobe");
-
- sigfillset(&blocked);
- sigprocmask(SIG_BLOCK, &blocked, NULL);
- flush_signals(current);

printk(KERN_INFO "adb: starting probe task...\n");
do_adb_reset_bus();
printk(KERN_INFO "adb: finished probe task...\n");

- adb_probe_task_pid = 0;
+ adb_probe_task = NULL;
up(&adb_probe_mutex);

return 0;
}

-static void
-__adb_probe_task(struct work_struct *bullshit)
-{
- adb_probe_task_pid = kernel_thread(adb_probe_task, NULL, SIGCHLD | CLONE_KERNEL);
-}
-
-static DECLARE_WORK(adb_reset_work, __adb_probe_task);
-
int
adb_reset_bus(void)
{
@@ -283,7 +267,7 @@ adb_reset_bus(void)
}

down(&adb_probe_mutex);
- schedule_work(&adb_reset_work);
+ adb_probe_task = kthread_run(adb_probe, NULL, "kadbprobe");
return 0;
}

@@ -469,9 +453,7 @@ adb_request(struct adb_request *req, void (*done)(struct adb_request *),
/* Synchronous requests send from the probe thread cause it to
* block. Beware that the "done" callback will be overriden !
*/
- if ((flags & ADBREQ_SYNC) &&
- (current->pid && adb_probe_task_pid &&
- adb_probe_task_pid == current->pid)) {
+ if ((flags & ADBREQ_SYNC) && (current == adb_probe_task)) {
req->done = adb_probe_wakeup;
rc = adb_controller->send_request(req, 0);
if (rc || req->complete)
--
1.5.0.g53756
-
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