diff options
Diffstat (limited to 'arch/mips/kernel/rtlx.c')
-rw-r--r-- | arch/mips/kernel/rtlx.c | 104 |
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); |