For write(), don't bother writing data to buffer if command already

finished, as the data won't be used anyway.  This allows user code to
see the command has finished before it has refilled the buffer completely.

diff --git a/comedi/comedi_fops.c b/comedi/comedi_fops.c
index 9a5e0ea2a6e9095869b13c02af45ff24d1433a6c..a638667547d5ac86cac0bed37765b77716536c35 100644 (file)
--- a/comedi/comedi_fops.c
+++ b/comedi/comedi_fops.c
@@ -1580,6 +1580,19 @@ static ssize_t comedi_write(struct file *file, const char *buf, size_t nbytes,
        while (nbytes > 0 && !retval) {
                set_current_state(TASK_INTERRUPTIBLE);
 
+               if (!(comedi_get_subdevice_runflags(s) & SRF_RUNNING)) {
+                       if (count == 0) {
+                               if (comedi_get_subdevice_runflags(s) &
+                                       SRF_ERROR) {
+                                       retval = -EPIPE;
+                               } else {
+                                       retval = 0;
+                               }
+                               do_become_nonbusy(dev, s);
+                       }
+                       break;
+               }
+
                n = nbytes;
 
                m = n;
@@ -1594,16 +1607,6 @@ static ssize_t comedi_write(struct file *file, const char *buf, size_t nbytes,
                        n = m;
 
                if (n == 0) {
-                       if (!(comedi_get_subdevice_runflags(s) & SRF_RUNNING)) {
-                               if (comedi_get_subdevice_runflags(s) &
-                                       SRF_ERROR) {
-                                       retval = -EPIPE;
-                               } else {
-                                       retval = 0;
-                               }
-                               do_become_nonbusy(dev, s);
-                               break;
-                       }
                        if (file->f_flags & O_NONBLOCK) {
                                retval = -EAGAIN;
                                break;