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Commit b8acb808 authored by Max Asbock's avatar Max Asbock Committed by Linus Torvalds
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[PATCH] ibmasm driver: correctly wake up sleeping threads 



Due to my incomplete understanding of the wait_event_interruptible() function
threads waiting for service processor events were not woken up.  This patch
fixes that problem.

Signed-off-by: default avatarMax Asbock <masbock@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f5ccc842

drivers/misc/ibmasm/event.c

+12 −6
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
 */



#include "ibmasm.h"

#include "lowlevel.h"



/*

 * ASM service processor event handling routines.
@@ -34,7 +35,6 @@ 
 * circular buffer.

 */





static void wake_up_event_readers(struct service_processor *sp)

{

	struct event_reader *reader;
@@ -63,7 +63,7 @@ void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int 
	spin_lock_irqsave(&sp->lock, flags);

	/* copy the event into the next slot in the circular buffer */

	event = &buffer->events[buffer->next_index];

	memcpy(event->data, data, data_size);

	memcpy_fromio(event->data, data, data_size);

	event->data_size = data_size;

	event->serial_number = buffer->next_serial_number;
@@ -93,7 +93,10 @@ int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *rea 
	unsigned int index;

	unsigned long flags;



	if (wait_event_interruptible(reader->wait, event_available(buffer, reader)))

	reader->cancelled = 0;



	if (wait_event_interruptible(reader->wait,

			event_available(buffer, reader) || reader->cancelled))

		return -ERESTARTSYS;



	if (!event_available(buffer, reader))
@@ -116,6 +119,12 @@ int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *rea 
	return event->data_size;

}



void ibmasm_cancel_next_event(struct event_reader *reader)

{

        reader->cancelled = 1;

        wake_up_interruptible(&reader->wait);

}



void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader)

{

	unsigned long flags;
@@ -131,8 +140,6 @@ void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_r 
{

	unsigned long flags;



	wake_up_interruptible(&reader->wait);



	spin_lock_irqsave(&sp->lock, flags);

	list_del(&reader->node);

	spin_unlock_irqrestore(&sp->lock, flags);
@@ -164,6 +171,5 @@ int ibmasm_event_buffer_init(struct service_processor *sp) 


void ibmasm_event_buffer_exit(struct service_processor *sp)

{

	wake_up_event_readers(sp);

	kfree(sp->event_buffer);

}

drivers/misc/ibmasm/ibmasm.h

+2 −0
Original line number Diff line number Diff line
@@ -108,6 +108,7 @@ struct event_buffer { 
};



struct event_reader {

	int			cancelled;

	unsigned int		next_serial_number;

	wait_queue_head_t	wait;

	struct list_head	node;
@@ -185,6 +186,7 @@ extern void ibmasm_receive_event(struct service_processor *sp, void *data, unsi 
extern void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader);

extern void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader);

extern int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader);

extern void ibmasm_cancel_next_event(struct event_reader *reader);



/* heartbeat - from SP to OS */

extern void ibmasm_register_panic_notifier(void);

drivers/misc/ibmasm/ibmasmfs.c

+26 −8
Original line number Diff line number Diff line
@@ -374,6 +374,7 @@ static int event_file_open(struct inode *inode, struct file *file) 
	ibmasm_event_reader_register(sp, &event_data->reader);



	event_data->sp = sp;

	event_data->active = 0;

	file->private_data = event_data;

	return 0;

}
@@ -391,7 +392,9 @@ static ssize_t event_file_read(struct file *file, char __user *buf, size_t count 
{

	struct ibmasmfs_event_data *event_data = file->private_data;

	struct event_reader *reader = &event_data->reader;

	struct service_processor *sp = event_data->sp;

	int ret;

	unsigned long flags;



	if (*offset < 0)

		return -EINVAL;
@@ -400,17 +403,32 @@ static ssize_t event_file_read(struct file *file, char __user *buf, size_t count 
	if (*offset != 0)

		return 0;



	ret = ibmasm_get_next_event(event_data->sp, reader);

	spin_lock_irqsave(&sp->lock, flags);

	if (event_data->active) {

		spin_unlock_irqrestore(&sp->lock, flags);

		return -EBUSY;

	}

	event_data->active = 1;

	spin_unlock_irqrestore(&sp->lock, flags);



	ret = ibmasm_get_next_event(sp, reader);

	if (ret <= 0)

		return ret;

		goto out;



	if (count < reader->data_size)

		return -EINVAL;

	if (count < reader->data_size) {

		ret = -EINVAL;

		goto out;

	}



        if (copy_to_user(buf, reader->data, reader->data_size))

		return -EFAULT;

        if (copy_to_user(buf, reader->data, reader->data_size)) {

		ret = -EFAULT;

		goto out;

	}

	ret = reader->data_size;



	return reader->data_size;

out:

	event_data->active = 0;

	return ret;

}



static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
@@ -424,7 +442,7 @@ static ssize_t event_file_write(struct file *file, const char __user *buf, size_ 
	if (*offset != 0)

		return 0;



	wake_up_interruptible(&event_data->reader.wait);

	ibmasm_cancel_next_event(&event_data->reader);

	return 0;

}