linux-kernel - [PATCH] iio: buffer: remove null-checks for 'indio

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Date:   Tue, 7 Apr 2020 17:59:18 +0300
From:   Alexandru Ardelean <alexandru.ardelean@...log.com>
To:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <jic23@...nel.org>,
        Alexandru Ardelean <alexandru.ardelean@...log.com>
Subject: [PATCH] iio: buffer: remove null-checks for 'indio_dev->info'

Checking for 'indio_dev->info' is an impossible condition, since an IIO
device should NOT be able to register without that information.
The iio_device_register() function won't allow an IIO device to register if
'indio_dev->info' is NULL.

If that information somehow becomes NULL, then we're likely busted anyway
and we should crash the system, if we haven't already.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
---
 drivers/iio/industrialio-buffer.c | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index e6fa1a4e135d..c96071bfada8 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -54,10 +54,6 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 	size_t avail;
 	int flushed = 0;
 
-	/* wakeup if the device was unregistered */
-	if (!indio_dev->info)
-		return true;
-
 	/* drain the buffer if it was disabled */
 	if (!iio_buffer_is_active(buf)) {
 		to_wait = min_t(size_t, to_wait, 1);
@@ -109,9 +105,6 @@ ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
 	size_t to_wait;
 	int ret = 0;
 
-	if (!indio_dev->info)
-		return -ENODEV;
-
 	if (!rb || !rb->access->read)
 		return -EINVAL;
 
@@ -131,11 +124,6 @@ ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
 
 	add_wait_queue(&rb->pollq, &wait);
 	do {
-		if (!indio_dev->info) {
-			ret = -ENODEV;
-			break;
-		}
-
 		if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
 			if (signal_pending(current)) {
 				ret = -ERESTARTSYS;
@@ -171,7 +159,7 @@ __poll_t iio_buffer_poll(struct file *filp,
 	struct iio_dev *indio_dev = filp->private_data;
 	struct iio_buffer *rb = indio_dev->buffer;
 
-	if (!indio_dev->info || rb == NULL)
+	if (rb == NULL)
 		return 0;
 
 	poll_wait(filp, &rb->pollq, wait);
@@ -1100,11 +1088,6 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 		goto out_unlock;
 	}
 
-	if (indio_dev->info == NULL) {
-		ret = -ENODEV;
-		goto out_unlock;
-	}
-
 	ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
 
 out_unlock:
-- 
2.17.1