From: Nuno Sá <nuno.sa@analog.com>
Date: Thu, 16 Feb 2023 10:14:50 +0000 (+0100)
Subject: iio: buffer: correctly return bytes written in output buffers
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=1658d973b2f8fffd93d6d2ef6967e7dd6d207883;p=users%2Fjedix%2Flinux-maple.git

iio: buffer: correctly return bytes written in output buffers

commit b5184a26a28fac1d708b0bfeeb958a9260c2924c upstream.

If for some reason 'rb->access->write()' does not write the full
requested data and the O_NONBLOCK is set, we would return 'n' to
userspace which is not really truth. Hence, let's return the number of
bytes we effectively wrote.

Fixes: 9eeee3b0bf190 ("iio: Add output buffer support")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20230216101452.591805-2-nuno.sa@analog.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 228598b82a2f3..c56cf748fde19 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -220,7 +220,7 @@ static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
 	} while (ret == 0);
 	remove_wait_queue(&rb->pollq, &wait);
 
-	return ret < 0 ? ret : n;
+	return ret < 0 ? ret : written;
 }
 
 /**