From: Max Asbock Date: Wed, 22 Jun 2005 00:16:33 +0000 (-0700) Subject: [PATCH] ibmasm driver: correctly wake up sleeping threads X-Git-Tag: v2.6.13-rc4~130^2~202^2~62 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=b8acb808468a88a188d7c5aba3681c583a5785f9;p=linux-2.6-omap-h63xx.git [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: Max Asbock Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/misc/ibmasm/event.c b/drivers/misc/ibmasm/event.c index e100f34f158..fe1e819235a 100644 --- a/drivers/misc/ibmasm/event.c +++ b/drivers/misc/ibmasm/event.c @@ -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); } diff --git a/drivers/misc/ibmasm/ibmasm.h b/drivers/misc/ibmasm/ibmasm.h index 1e83406382e..35c4def5af1 100644 --- a/drivers/misc/ibmasm/ibmasm.h +++ b/drivers/misc/ibmasm/ibmasm.h @@ -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); diff --git a/drivers/misc/ibmasm/ibmasmfs.c b/drivers/misc/ibmasm/ibmasmfs.c index 866e867e68f..c87ef7d82b7 100644 --- a/drivers/misc/ibmasm/ibmasmfs.c +++ b/drivers/misc/ibmasm/ibmasmfs.c @@ -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; }