For output buffers, there's no guarantee that the buffer won't be full
in the first iteration of the loop in which case we would block
independently of userspace passing O_NONBLOCK or not. Fix it by always
checking the flag before going to sleep.
While at it (and as it's a bit related), refactored the loop so that the
stop condition is 'written != n', i.e, run the loop until all data has
been copied into the IIO buffers. This makes the code a bit simpler.
Fixes: 9eeee3b0bf190 ("iio: Add output buffer support")
Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
---
drivers/iio/industrialio-buffer.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index c56cf748fde1..7e7ee307a3f7 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -203,21 +203,24 @@ static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
break;
}
+ if (filp->f_flags & O_NONBLOCK) {
+ if (!written)
+ ret = -EAGAIN;
+ break;
+ }
+
wait_woken(&wait, TASK_INTERRUPTIBLE,
MAX_SCHEDULE_TIMEOUT);
continue;
}
ret = rb->access->write(rb, n - written, buf + written);
- if (ret == 0 && (filp->f_flags & O_NONBLOCK))
- ret = -EAGAIN;
+ if (ret < 0)
+ break;
- if (ret > 0) {
- written += ret;
- if (written != n && !(filp->f_flags & O_NONBLOCK))
- continue;
- }
- } while (ret == 0);
+ written += ret;
+
+ } while (written != n);
remove_wait_queue(&rb->pollq, &wait);
return ret < 0 ? ret : written;
--
2.39.2
