From 9ba3466e6336e288d366d4909fb35181b3f77aba Mon Sep 17 00:00:00 2001 From: =?utf8?q?Nuno=20S=C3=A1?= Date: Thu, 16 Feb 2023 11:14:51 +0100 Subject: [PATCH] iio: buffer: make sure O_NONBLOCK is respected MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 3da1814184582ed0faf039275a3f02e6f69944ee upstream. 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 Reviewed-by: Lars-Peter Clausen Link: https://lore.kernel.org/r/20230216101452.591805-3-nuno.sa@analog.com Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- 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; -- 2.50.1