diff options
Diffstat (limited to 'drivers/staging/comedi/comedi_fops.c')
| -rw-r--r-- | drivers/staging/comedi/comedi_fops.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index f39448a0d301..a979f621f932 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2491,11 +2491,11 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, add_wait_queue(&async->wait_head, &wait); while (nbytes > 0 && !retval) { + unsigned int rp, n1, n2; + set_current_state(TASK_INTERRUPTIBLE); m = comedi_buf_read_n_available(s); - if (async->buf_read_ptr + m > async->prealloc_bufsz) - m = async->prealloc_bufsz - async->buf_read_ptr; n = min_t(size_t, m, nbytes); if (n == 0) { @@ -2532,8 +2532,14 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, } continue; } - m = copy_to_user(buf, async->prealloc_buf + - async->buf_read_ptr, n); + rp = async->buf_read_ptr; + n1 = min(n, async->prealloc_bufsz - rp); + n2 = n - n1; + m = copy_to_user(buf, async->prealloc_buf + rp, n1); + if (m) + m += n2; + else if (n2) + m = copy_to_user(buf + n1, async->prealloc_buf, n2); if (m) { n -= m; retval = -EFAULT; |