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-rw-r--r--arch/mips/kernel/rtlx.c104
1 files changed, 62 insertions, 42 deletions
diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index e14ae09e..e6e3047 100644
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -54,6 +54,7 @@ static struct chan_waitqueues {
wait_queue_head_t rt_queue;
wait_queue_head_t lx_queue;
atomic_t in_open;
+ struct mutex mutex;
} channel_wqs[RTLX_CHANNELS];
static struct irqaction irq;
@@ -146,7 +147,7 @@ static void stopping(int vpe)
int rtlx_open(int index, int can_sleep)
{
- volatile struct rtlx_info **p;
+ struct rtlx_info **p;
struct rtlx_channel *chan;
enum rtlx_state state;
int ret = 0;
@@ -179,13 +180,24 @@ int rtlx_open(int index, int can_sleep)
}
}
+ smp_rmb();
if (*p == NULL) {
if (can_sleep) {
- __wait_event_interruptible(channel_wqs[index].lx_queue,
- *p != NULL,
- ret);
- if (ret)
+ 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;
+ }
+ finish_wait(&channel_wqs[index].lx_queue, &wait);
} else {
printk(" *vpe_get_shared is NULL. "
"Has an SP program been loaded?\n");
@@ -277,56 +289,52 @@ unsigned int rtlx_write_poll(int index)
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)
-{
- 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)
+ssize_t rtlx_read(int index, void __user *buff, 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);
- /* update the index */
- lx->lx_read += count;
- lx->lx_read %= lx->buffer_size;
+out:
+ count -= failed;
+
+ 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)
@@ -334,24 +342,35 @@ ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
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);
+ }
+
+out:
+ count -= cailed;
- rt->rt_write += count;
- rt->rt_write %= rt->buffer_size;
+ smp_wmb();
+ rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
+ smp_wmb();
+ mutex_unlock(&channel_wqs[index].mutex);
- return(count);
+ return count;
}
@@ -403,7 +422,7 @@ static ssize_t file_read(struct file *file, char __user * buffer, size_t 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,
@@ -429,7 +448,7 @@ static ssize_t file_write(struct file *file, const char __user * buffer,
return ret;
}
- return rtlx_write(minor, (void *)buffer, count, 1);
+ return rtlx_write(minor, buffer, count);
}
static const struct file_operations rtlx_fops = {
@@ -468,6 +487,7 @@ static int rtlx_module_init(void)
init_waitqueue_head(&channel_wqs[i].rt_queue);
init_waitqueue_head(&channel_wqs[i].lx_queue);
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);
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