static struct chan_waitqueues {
wait_queue_head_t rt_queue;
wait_queue_head_t lx_queue;
- int in_open;
+ atomic_t in_open;
+ struct mutex mutex;
} channel_wqs[RTLX_CHANNELS];
static struct irqaction irq;
int rtlx_open(int index, int can_sleep)
{
- int ret;
+ struct rtlx_info **p;
struct rtlx_channel *chan;
- volatile struct rtlx_info **p;
+ enum rtlx_state state;
+ int ret = 0;
if (index >= RTLX_CHANNELS) {
printk(KERN_DEBUG "rtlx_open index out of range\n");
return -ENOSYS;
}
- if (channel_wqs[index].in_open) {
- printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
- return -EBUSY;
+ if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
+ printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
+ index);
+ ret = -EBUSY;
+ goto out_fail;
}
- channel_wqs[index].in_open++;
-
if (rtlx == NULL) {
if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
if (can_sleep) {
- DECLARE_WAITQUEUE(wait, current);
-
- /* go to sleep */
- add_wait_queue(&channel_wqs[index].lx_queue, &wait);
-
- set_current_state(TASK_INTERRUPTIBLE);
- while ((p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
- schedule();
- set_current_state(TASK_INTERRUPTIBLE);
- }
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
-
- /* back running */
+ __wait_event_interruptible(channel_wqs[index].lx_queue,
+ (p = vpe_get_shared(RTLX_TARG_VPE)),
+ ret);
+ if (ret)
+ goto out_fail;
} else {
- printk( KERN_DEBUG "No SP program loaded, and device "
+ printk(KERN_DEBUG "No SP program loaded, and device "
"opened with O_NONBLOCK\n");
- channel_wqs[index].in_open = 0;
- return -ENOSYS;
+ ret = -ENOSYS;
+ goto out_fail;
}
}
+ smp_rmb();
if (*p == NULL) {
if (can_sleep) {
- DECLARE_WAITQUEUE(wait, current);
-
- /* go to sleep */
- add_wait_queue(&channel_wqs[index].lx_queue, &wait);
-
- set_current_state(TASK_INTERRUPTIBLE);
- while (*p == NULL) {
- schedule();
-
- /* reset task state to interruptable otherwise
- we'll whizz round here like a very fast loopy
- thing. schedule() appears to return with state
- set to TASK_RUNNING.
-
- If the loaded SP program, for whatever reason,
- doesn't set up the shared structure *p will never
- become true. So whoever connected to either /dev/rt?
- or if it was kspd, will then take up rather a lot of
- processor cycles.
- */
-
- set_current_state(TASK_INTERRUPTIBLE);
+ DEFINE_WAIT(wait);
+
+ for (;;) {
+ prepare_to_wait(&channel_wqs[index].lx_queue, &wait, TASK_INTERRUPTIBLE);
+ smp_rmb();
+ if (*p != NULL)
+ break;
+ if (!signal_pending(current)) {
+ schedule();
+ continue;
+ }
+ ret = -ERESTARTSYS;
+ goto out_fail;
}
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
-
- /* back running */
- }
- else {
+ finish_wait(&channel_wqs[index].lx_queue, &wait);
+ } else {
printk(" *vpe_get_shared is NULL. "
"Has an SP program been loaded?\n");
- channel_wqs[index].in_open = 0;
- return -ENOSYS;
+ ret = -ENOSYS;
+ goto out_fail;
}
}
if ((unsigned int)*p < KSEG0) {
printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
"maybe an error code %d\n", (int)*p);
- channel_wqs[index].in_open = 0;
- return -ENOSYS;
+ ret = -ENOSYS;
+ goto out_fail;
}
- if ((ret = rtlx_init(*p)) < 0) {
- channel_wqs[index].in_open = 0;
- return ret;
- }
+ if ((ret = rtlx_init(*p)) < 0)
+ goto out_ret;
}
chan = &rtlx->channel[index];
- if (chan->lx_state == RTLX_STATE_OPENED) {
- channel_wqs[index].in_open = 0;
- return -EBUSY;
- }
+ state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
+ if (state == RTLX_STATE_OPENED) {
+ ret = -EBUSY;
+ goto out_fail;
+ }
- chan->lx_state = RTLX_STATE_OPENED;
- channel_wqs[index].in_open = 0;
- return 0;
+out_fail:
+ smp_mb();
+ atomic_dec(&channel_wqs[index].in_open);
+ smp_mb();
+
+out_ret:
+ return ret;
}
int rtlx_release(int index)
/* data available to read? */
if (chan->lx_read == chan->lx_write) {
if (can_sleep) {
- DECLARE_WAITQUEUE(wait, current);
-
- /* go to sleep */
- add_wait_queue(&channel_wqs[index].lx_queue, &wait);
-
- set_current_state(TASK_INTERRUPTIBLE);
- while (chan->lx_read == chan->lx_write) {
- schedule();
+ int ret = 0;
- set_current_state(TASK_INTERRUPTIBLE);
+ __wait_event_interruptible(channel_wqs[index].lx_queue,
+ chan->lx_read != chan->lx_write || sp_stopping,
+ ret);
+ if (ret)
+ return ret;
- if (sp_stopping) {
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
- return 0;
- }
- }
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
-
- /* back running */
- }
- else
+ if (sp_stopping)
+ return 0;
+ } else
return 0;
}
return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
}
-static inline void copy_to(void *dst, void *src, size_t count, int user)
+ssize_t rtlx_read(int index, void __user *buff, size_t count, int user)
{
- if (user)
- copy_to_user(dst, src, count);
- else
- memcpy(dst, src, count);
-}
-
-static inline void copy_from(void *dst, void *src, size_t count, int user)
-{
- if (user)
- copy_from_user(dst, src, count);
- else
- memcpy(dst, src, count);
-}
-
-ssize_t rtlx_read(int index, void *buff, size_t count, int user)
-{
- size_t fl = 0L;
+ size_t lx_write, fl = 0L;
struct rtlx_channel *lx;
+ unsigned long failed;
if (rtlx == NULL)
return -ENOSYS;
lx = &rtlx->channel[index];
+ mutex_lock(&channel_wqs[index].mutex);
+ smp_rmb();
+ lx_write = lx->lx_write;
+
/* find out how much in total */
count = min(count,
- (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read)
+ (size_t)(lx_write + lx->buffer_size - lx->lx_read)
% lx->buffer_size);
/* then how much from the read pointer onwards */
- fl = min( count, (size_t)lx->buffer_size - lx->lx_read);
+ fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
- copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
+ failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
+ if (failed)
+ goto out;
/* and if there is anything left at the beginning of the buffer */
- if ( count - fl )
- copy_to (buff + fl, lx->lx_buffer, count - fl, user);
+ if (count - fl)
+ failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
+
+out:
+ count -= failed;
- /* update the index */
- lx->lx_read += count;
- lx->lx_read %= lx->buffer_size;
+ smp_wmb();
+ lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
+ smp_wmb();
+ mutex_unlock(&channel_wqs[index].mutex);
return count;
}
-ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
+ssize_t rtlx_write(int index, const void __user *buffer, size_t count, int user)
{
struct rtlx_channel *rt;
+ size_t rt_read;
size_t fl;
if (rtlx == NULL)
rt = &rtlx->channel[index];
+ mutex_lock(&channel_wqs[index].mutex);
+ smp_rmb();
+ rt_read = rt->rt_read;
+
/* total number of bytes to copy */
count = min(count,
- (size_t)write_spacefree(rt->rt_read, rt->rt_write,
- rt->buffer_size));
+ (size_t)write_spacefree(rt_read, rt->rt_write, rt->buffer_size));
/* first bit from write pointer to the end of the buffer, or count */
fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
- copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
+ failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
+ if (failed)
+ goto out;
/* if there's any left copy to the beginning of the buffer */
- if( count - fl )
- copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
+ if (count - fl) {
+ failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
+ }
- rt->rt_write += count;
- rt->rt_write %= rt->buffer_size;
+out:
+ count -= cailed;
- return(count);
+ smp_wmb();
+ rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
+ smp_wmb();
+ mutex_unlock(&channel_wqs[index].mutex);
+
+ return count;
}
return 0; // -EAGAIN makes cat whinge
}
- return rtlx_read(minor, buffer, count, 1);
+ return rtlx_read(minor, buffer, count);
}
static ssize_t file_write(struct file *file, const char __user * buffer,
{
int minor;
struct rtlx_channel *rt;
- DECLARE_WAITQUEUE(wait, current);
minor = iminor(file->f_path.dentry->d_inode);
rt = &rtlx->channel[minor];
/* any space left... */
if (!rtlx_write_poll(minor)) {
+ int ret = 0;
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
- add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
-
- while (!rtlx_write_poll(minor))
- schedule();
-
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
+ __wait_event_interruptible(channel_wqs[minor].rt_queue,
+ rtlx_write_poll(minor),
+ ret);
+ if (ret)
+ return ret;
}
- return rtlx_write(minor, (void *)buffer, count, 1);
+ return rtlx_write(minor, buffer, count);
}
static const struct file_operations rtlx_fops = {
for (i = 0; i < RTLX_CHANNELS; i++) {
init_waitqueue_head(&channel_wqs[i].rt_queue);
init_waitqueue_head(&channel_wqs[i].lx_queue);
- channel_wqs[i].in_open = 0;
+ atomic_set(&channel_wqs[i].in_open, 0);
+ mutex_init(&channel_wqs[i].mutex);
dev = device_create(mt_class, NULL, MKDEV(major, i),
"%s%d", module_name, i);
git.openpandora.org / pandora-kernel.git / blobdiff