Commit 3b4c7d64 authored by Sukadev Bhattiprolu's avatar Sukadev Bhattiprolu Committed by John W. Linville
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[PATCH] kthread: airo.c 



The airo driver is currently caching a pid for later use, but with the
implementation of containers, pids themselves do not uniquely identify a
task.  The driver is also using kernel_thread() which is deprecated in
drivers.

This patch essentially replaces the kernel_thread() with kthread_create().
It also stores the task_struct of the airo_thread rather than its pid.
Since this introduces a second task_struct in struct airo_info, the patch
renames airo_info.task to airo_info.list_bss_task.

As an extension of these changes, the patch further:

	 - replaces kill_proc() with kthread_stop()
	 - replaces signal_pending() with kthread_should_stop()
	 - removes thread completion synchronisation which is handled by
	   kthread_stop().

[akpm@osdl.org: fix races]
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Javier Achirica <achirica@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent e4ac2663

drivers/net/wireless/airo.c

+16 −24
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <linux/pci.h>

#include <asm/uaccess.h>

#include <net/ieee80211.h>

#include <linux/kthread.h>



#include "airo.h"
@@ -1187,11 +1188,10 @@ struct airo_info { 
			int whichbap);

	unsigned short *flash;

	tdsRssiEntry *rssi;

	struct task_struct *task;

	struct task_struct *list_bss_task;

	struct task_struct *airo_thread_task;

	struct semaphore sem;

	pid_t thr_pid;

	wait_queue_head_t thr_wait;

	struct completion thr_exited;

	unsigned long expires;

	struct {

		struct sk_buff *skb;
@@ -1733,12 +1733,12 @@ static int readBSSListRid(struct airo_info *ai, int first, 
		cmd.cmd=CMD_LISTBSS;

		if (down_interruptible(&ai->sem))

			return -ERESTARTSYS;

		ai->list_bss_task = current;

		issuecommand(ai, &cmd, &rsp);

		up(&ai->sem);

		/* Let the command take effect */

		ai->task = current;

		ssleep(3);

		ai->task = NULL;

		schedule_timeout_uninterruptible(3 * HZ);

		ai->list_bss_task = NULL;

	}

	rc = PC4500_readrid(ai, first ? ai->bssListFirst : ai->bssListNext,

			    list, ai->bssListRidLen, 1);
@@ -2400,8 +2400,7 @@ void stop_airo_card( struct net_device *dev, int freeres ) 
		clear_bit(FLAG_REGISTERED, &ai->flags);

	}

	set_bit(JOB_DIE, &ai->jobs);

	kill_proc(ai->thr_pid, SIGTERM, 1);

	wait_for_completion(&ai->thr_exited);

	kthread_stop(ai->airo_thread_task);



	/*

	 * Clean out tx queue
@@ -2811,9 +2810,8 @@ static struct net_device *_init_airo_card( unsigned short irq, int port, 
	ai->config.len = 0;

	ai->pci = pci;

	init_waitqueue_head (&ai->thr_wait);

	init_completion (&ai->thr_exited);

	ai->thr_pid = kernel_thread(airo_thread, dev, CLONE_FS | CLONE_FILES);

	if (ai->thr_pid < 0)

	ai->airo_thread_task = kthread_run(airo_thread, dev, dev->name);

	if (IS_ERR(ai->airo_thread_task))

		goto err_out_free;

	ai->tfm = NULL;

	rc = add_airo_dev( dev );
@@ -2930,8 +2928,7 @@ err_out_unlink: 
	del_airo_dev(dev);

err_out_thr:

	set_bit(JOB_DIE, &ai->jobs);

	kill_proc(ai->thr_pid, SIGTERM, 1);

	wait_for_completion(&ai->thr_exited);

	kthread_stop(ai->airo_thread_task);

err_out_free:

	free_netdev(dev);

	return NULL;
@@ -3063,13 +3060,7 @@ static int airo_thread(void *data) { 
	struct airo_info *ai = dev->priv;

	int locked;

	

	daemonize("%s", dev->name);

	allow_signal(SIGTERM);



	while(1) {

		if (signal_pending(current))

			flush_signals(current);



		/* make swsusp happy with our thread */

		try_to_freeze();
@@ -3097,7 +3088,7 @@ static int airo_thread(void *data) { 
						set_bit(JOB_AUTOWEP, &ai->jobs);

						break;

					}

					if (!signal_pending(current)) {

					if (!kthread_should_stop()) {

						unsigned long wake_at;

						if (!ai->expires || !ai->scan_timeout) {

							wake_at = max(ai->expires,
@@ -3109,7 +3100,7 @@ static int airo_thread(void *data) { 
						schedule_timeout(wake_at - jiffies);

						continue;

					}

				} else if (!signal_pending(current)) {

				} else if (!kthread_should_stop()) {

					schedule();

					continue;

				}
@@ -3154,7 +3145,8 @@ static int airo_thread(void *data) { 
		else  /* Shouldn't get here, but we make sure to unlock */

			up(&ai->sem);

	}

	complete_and_exit (&ai->thr_exited, 0);



	return 0;

}



static irqreturn_t airo_interrupt ( int irq, void* dev_id, struct pt_regs *regs) {
@@ -3235,8 +3227,8 @@ static irqreturn_t airo_interrupt ( int irq, void* dev_id, struct pt_regs *regs) 
			if(newStatus == ASSOCIATED || newStatus == REASSOCIATED) {

				if (auto_wep)

					apriv->expires = 0;

				if (apriv->task)

					wake_up_process (apriv->task);

				if (apriv->list_bss_task)

					wake_up_process(apriv->list_bss_task);

				set_bit(FLAG_UPDATE_UNI, &apriv->flags);

				set_bit(FLAG_UPDATE_MULTI, &apriv->flags);

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