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From: Alexandru Ardelean <alexandru.ardelean@analog.com>
To: <linux-kernel@vger.kernel.org>, <linux-iio@vger.kernel.org>
Cc: <lars@metafoo.de>, <Michael.Hennerich@analog.com>,
	<jic23@kernel.org>, <nuno.sa@analog.com>,
	<dragos.bogdan@analog.com>,
	Alexandru Ardelean <alexandru.ardelean@analog.com>
Subject: [PATCH v2 10/12][RESEND] iio: core: wrap iio device & buffer into struct for character devices
Date: Fri, 22 Jan 2021 18:25:27 +0200	[thread overview]
Message-ID: <20210122162529.84978-11-alexandru.ardelean@analog.com> (raw)
In-Reply-To: <20210122162529.84978-1-alexandru.ardelean@analog.com>

In order to keep backwards compatibility with the current chardev
mechanism, and in order to add support for multiple buffers per IIO device,
we need to pass both the IIO device & IIO buffer to the chardev.

This is particularly needed for the iio_buffer_read_outer() function, where
we need to pass another buffer object than 'indio_dev->buffer'.

Since we'll also open some chardevs via anon inodes, we can pass extra
buffers in that function by assigning another object to the
iio_dev_buffer_pair object.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/iio/iio_core.h            |  6 ++++++
 drivers/iio/industrialio-buffer.c | 10 ++++++----
 drivers/iio/industrialio-core.c   | 18 ++++++++++++++++--
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
index 43d44ec92781..ad6716fe1a93 100644
--- a/drivers/iio/iio_core.h
+++ b/drivers/iio/iio_core.h
@@ -12,11 +12,17 @@
 #include <linux/kernel.h>
 #include <linux/device.h>
 
+struct iio_buffer;
 struct iio_chan_spec;
 struct iio_dev;
 
 extern struct device_type iio_device_type;
 
+struct iio_dev_buffer_pair {
+	struct iio_dev		*indio_dev;
+	struct iio_buffer	*buffer;
+};
+
 #define IIO_IOCTL_UNHANDLED	1
 struct iio_ioctl_handler {
 	struct list_head entry;
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 887c71272e9c..62cb90385246 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -112,8 +112,9 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
 			      size_t n, loff_t *f_ps)
 {
-	struct iio_dev *indio_dev = filp->private_data;
-	struct iio_buffer *rb = indio_dev->buffer;
+	struct iio_dev_buffer_pair *ib = filp->private_data;
+	struct iio_buffer *rb = ib->buffer;
+	struct iio_dev *indio_dev = ib->indio_dev;
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	size_t datum_size;
 	size_t to_wait;
@@ -178,8 +179,9 @@ ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
 __poll_t iio_buffer_poll(struct file *filp,
 			     struct poll_table_struct *wait)
 {
-	struct iio_dev *indio_dev = filp->private_data;
-	struct iio_buffer *rb = indio_dev->buffer;
+	struct iio_dev_buffer_pair *ib = filp->private_data;
+	struct iio_buffer *rb = ib->buffer;
+	struct iio_dev *indio_dev = ib->indio_dev;
 
 	if (!indio_dev->info || rb == NULL)
 		return 0;
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 088e59042226..0d1880837776 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1666,13 +1666,24 @@ static int iio_chrdev_open(struct inode *inode, struct file *filp)
 {
 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
 						struct iio_dev, chrdev);
+	struct iio_dev_buffer_pair *ib;
 
 	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))
 		return -EBUSY;
 
 	iio_device_get(indio_dev);
 
-	filp->private_data = indio_dev;
+	ib = kmalloc(sizeof(*ib), GFP_KERNEL);
+	if (!ib) {
+		iio_device_put(indio_dev);
+		clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
+		return -ENOMEM;
+	}
+
+	ib->indio_dev = indio_dev;
+	ib->buffer = indio_dev->buffer;
+
+	filp->private_data = ib;
 
 	return 0;
 }
@@ -1686,10 +1697,12 @@ static int iio_chrdev_open(struct inode *inode, struct file *filp)
  */
 static int iio_chrdev_release(struct inode *inode, struct file *filp)
 {
+	struct iio_dev_buffer_pair *ib = filp->private_data;
 	struct iio_dev *indio_dev = container_of(inode->i_cdev,
 						struct iio_dev, chrdev);
 	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);
 	iio_device_put(indio_dev);
+	kfree(ib);
 
 	return 0;
 }
@@ -1709,7 +1722,8 @@ void iio_device_ioctl_handler_unregister(struct iio_ioctl_handler *h)
 
 static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-	struct iio_dev *indio_dev = filp->private_data;
+	struct iio_dev_buffer_pair *ib = filp->private_data;
+	struct iio_dev *indio_dev = ib->indio_dev;
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	struct iio_ioctl_handler *h;
 	int ret = -ENODEV;
-- 
2.17.1


  parent reply	other threads:[~2021-01-22 17:08 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-22 16:25 [PATCH v2 00/12][RESEND] iio: core,buffer: add support for multiple IIO buffers per IIO device Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 01/12][RESEND] iio: core: register chardev only if needed Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 02/12][RESEND] iio: buffer: add back-ref from iio_buffer to iio_dev Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 03/12][RESEND] iio: buffer: rework buffer & scan_elements dir creation Alexandru Ardelean
2021-01-24 18:11   ` Jonathan Cameron
2021-01-24 19:07     ` Alexandru Ardelean
2021-01-25 19:29       ` Greg Kroah-Hartman
2021-01-25 19:28     ` Greg Kroah-Hartman
2021-01-26  9:45       ` Alexandru Ardelean
2021-01-27 14:48         ` Jonathan Cameron
2021-01-22 16:25 ` [PATCH v2 04/12][RESEND] iio: buffer: add index to the first IIO buffer dir and symlink it back Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 05/12][RESEND] iio: core: split __iio_device_attr_init() to init only the attr object Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 06/12][RESEND] iio: buffer: re-route scan_elements via it's kobj_type Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 07/12][RESEND] iio: buffer: re-route core buffer attributes via it's new kobj_type Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 08/12][RESEND] iio: buffer: add helper to get the IIO device to which a buffer belongs Alexandru Ardelean
2021-01-22 16:25 ` [PATCH v2 09/12][RESEND] iio: re-route all buffer attributes through new buffer kobj_type Alexandru Ardelean
2021-01-22 16:25 ` Alexandru Ardelean [this message]
2021-01-22 16:25 ` [PATCH v2 11/12][RESEND] iio: buffer: introduce support for attaching more IIO buffers Alexandru Ardelean
2021-01-25 11:06   ` [kbuild] " Dan Carpenter
2021-01-22 16:25 ` [PATCH v2 12/12][RESEND] iio: buffer: add ioctl() to support opening extra buffers for IIO device Alexandru Ardelean
2021-01-24 18:38   ` Jonathan Cameron
2021-01-24 19:32     ` Alexandru Ardelean

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