On Mon, 2020-04-13 at 16:58 +0100, Jonathan Cameron wrote:
> [External]
>
> On Fri, 10 Apr 2020 17:17:27 +0300
> Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:
>
> > This change makes the first jump to move the buffer chardev from indio_dev
> > to the buffer attached to indio_dev (i.e. indio_dev->buffer).
> >
> > This requires that some functions that are shared between
> > 'industrialio-core.c' & industrialio-buffer.c be re-shuffled.
> > The 'iio_buffer_fileops' is now moved to 'industrialio-buffer.c'. It's also
> > more appropriate to have it here, but the old 'legacy' iio_ioctl() must be
> > passed to it.
> >
> > What happens now is:
> > * if IS_ENABLED(CONFIG_IIO_BUFFER) and 'indio_dev->buffer != NULL' the
> > indio_dev->buffer->chrdev will be initialized (as the old legacy style
> > chardev)
> > * if -ENOTSUPP is returned for either of the conditions above (not being
> > met), the chardev will be created directly via 'indio_dev->chrdev', same
> > as before; a new field is required now 'indio_dev->chrdev_initialized' to
> > mark it true, so that 'indio_dev->chrdev' gets deleted if initialized;
> >
> > 'indio_dev->chrdev_initialized' is of type 'int', because recently
> > checkpatch complains that 'bool' types on structs can cause alignment
> > issues.
> >
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
>
> I wonder if it would be possible to make the ioctl mess a bit cleaner.
> Have the buffer ioctl function as here, but have that call a generic
> iio_device_ioctl function in industrialio-core.c which can in theory
> handle 'device wide' ioctls. Then have the events code register into
> that as a consumer of a particular device wide ioctl.
>
> That way the layering is a violated a little less.
>
> What do you think?
I like it.
Will create a patch for that.
I'll see if I can make it neat into this series somehow.
Otherwise, would it be ok to do it on top of this series?
I currently don't have a clear idea of how clean the patchset would look.
>
> Jonathan
>
> > ---
> > drivers/iio/iio_core.h | 25 ++++---
> > drivers/iio/industrialio-buffer.c | 119 ++++++++++++++++++++++++++++--
> > drivers/iio/industrialio-core.c | 59 ++++++++-------
> > include/linux/iio/buffer_impl.h | 7 ++
> > include/linux/iio/iio.h | 2 +
> > 5 files changed, 170 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
> > index fd9a5f1d5e51..4bdadeac2710 100644
> > --- a/drivers/iio/iio_core.h
> > +++ b/drivers/iio/iio_core.h
> > @@ -40,24 +40,31 @@ ssize_t iio_format_value(char *buf, unsigned int type,
> > int size, int *vals);
> > #ifdef CONFIG_IIO_BUFFER
> > struct poll_table_struct;
> >
> > -__poll_t iio_buffer_poll(struct file *filp,
> > - struct poll_table_struct *wait);
> > -ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
> > - size_t n, loff_t *f_ps);
> > +long iio_device_event_ioctl(struct iio_dev *indio_dev, struct file *filp,
> > + unsigned int cmd, unsigned long arg);
> > +
> > +int iio_device_buffers_init(struct iio_dev *indio_dev, struct module
> > *this_mod);
> > +void iio_device_buffers_uninit(struct iio_dev *indio_dev);
> > +
> > +void iio_device_buffers_put(struct iio_dev *indio_dev);
> >
> > int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev);
> > void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev);
> >
> > -#define iio_buffer_poll_addr (&iio_buffer_poll)
> > -#define iio_buffer_read_outer_addr (&iio_buffer_read_outer)
> > -
> > void iio_disable_all_buffers(struct iio_dev *indio_dev);
> > void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);
> >
> > #else
> >
> > -#define iio_buffer_poll_addr NULL
> > -#define iio_buffer_read_outer_addr NULL
> > +static inline int iio_device_buffers_init(struct iio_dev *indio_dev,
> > + struct module *this_mod)
> > +{
> > + return -ENOTSUPP;
> > +}
> > +
> > +static inline void iio_device_buffers_uninit(struct iio_dev *indio_dev) {}
> > +
> > +static inline void iio_device_buffers_put(struct iio_dev *indio_dev) {}
> >
> > static inline int iio_buffer_alloc_sysfs_and_mask(struct iio_dev
> > *indio_dev)
> > {
> > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-
> > buffer.c
> > index f9ffc7762f6c..4b5c3baadaab 100644
> > --- a/drivers/iio/industrialio-buffer.c
> > +++ b/drivers/iio/industrialio-buffer.c
> > @@ -99,11 +99,11 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev,
> > struct iio_buffer *buf,
> > * Return: negative values corresponding to error codes or ret != 0
> > * for ending the reading activity
> > **/
> > -ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
> > - size_t n, loff_t *f_ps)
> > +static 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_buffer *rb = filp->private_data;
> > + struct iio_dev *indio_dev = rb->indio_dev;
> > DEFINE_WAIT_FUNC(wait, woken_wake_function);
> > size_t datum_size;
> > size_t to_wait;
> > @@ -165,11 +165,11 @@ ssize_t iio_buffer_read_outer(struct file *filp, char
> > __user *buf,
> > * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
> > * or 0 for other cases
> > */
> > -__poll_t iio_buffer_poll(struct file *filp,
> > +static __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_buffer *rb = filp->private_data;
> > + struct iio_dev *indio_dev = rb->indio_dev;
> >
> > if (!indio_dev->info || rb == NULL)
> > return 0;
> > @@ -180,6 +180,48 @@ __poll_t iio_buffer_poll(struct file *filp,
> > return 0;
> > }
> >
> > +/**
> > + * iio_buffer_chrdev_open() - chrdev file open for buffer access
> > + * @inode: Inode structure for identifying the device in the file system
> > + * @filp: File structure for iio device used to keep and later access
> > + * private data
> > + *
> > + * Return: 0 on success or -EBUSY if the device is already opened
> > + **/
> > +static int iio_buffer_chrdev_open(struct inode *inode, struct file *filp)
> > +{
> > + struct iio_buffer *buffer = container_of(inode->i_cdev,
> > + struct iio_buffer, chrdev);
> > +
> > + if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->file_ops_flags))
> > + return -EBUSY;
> > +
> > + iio_buffer_get(buffer);
> > +
> > + filp->private_data = buffer;
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * iio_buffer_chrdev_release() - chrdev file close for buffer access
> > + * @inode: Inode structure pointer for the char device
> > + * @filp: File structure pointer for the char device
> > + *
> > + * Return: 0 for successful release
> > + */
> > +static int iio_buffer_chrdev_release(struct inode *inode, struct file
> > *filp)
> > +{
> > + struct iio_buffer *buffer = container_of(inode->i_cdev,
> > + struct iio_buffer, chrdev);
> > +
> > + clear_bit(IIO_BUSY_BIT_POS, &buffer->file_ops_flags);
> > +
> > + iio_buffer_put(buffer);
> > +
> > + return 0;
> > +}
> > +
> > /**
> > * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
> > * @indio_dev: The IIO device
> > @@ -1121,6 +1163,14 @@ void iio_disable_all_buffers(struct iio_dev
> > *indio_dev)
> > iio_buffer_deactivate_all(indio_dev);
> > }
> >
> > +long iio_buffer_ioctl(struct file *filep, unsigned int cmd, unsigned long
> > arg)
> > +{
> > + struct iio_buffer *buffer = filep->private_data;
> > + struct iio_dev *indio_dev = buffer->indio_dev;
> > +
> > + return iio_device_event_ioctl(indio_dev, filep, cmd, arg);
> > +}
> > +
> > static ssize_t iio_buffer_store_enable(struct device *dev,
> > struct device_attribute *attr,
> > const char *buf,
> > @@ -1356,6 +1406,61 @@ void iio_buffer_free_sysfs_and_mask(struct iio_dev
> > *indio_dev)
> > iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
> > }
> >
> > +static const struct file_operations iio_buffer_fileops = {
> > + .read = iio_buffer_read_outer,
> > + .release = iio_buffer_chrdev_release,
> > + .open = iio_buffer_chrdev_open,
> > + .poll = iio_buffer_poll,
> > + .owner = THIS_MODULE,
> > + .llseek = noop_llseek,
> > + .unlocked_ioctl = iio_buffer_ioctl,
> > + .compat_ioctl = compat_ptr_ioctl,
> > +};
> > +
> > +int iio_device_buffers_init(struct iio_dev *indio_dev, struct module
> > *this_mod)
> > +{
> > + struct iio_buffer *buffer = indio_dev->buffer;
> > + int ret;
> > +
> > + if (!buffer)
> > + return -ENOTSUPP;
> > +
> > + cdev_init(&buffer->chrdev, &iio_buffer_fileops);
> > +
> > + buffer->chrdev.owner = this_mod;
> > +
> > + ret = cdev_device_add(&buffer->chrdev, &indio_dev->dev);
> > + if (ret)
> > + return ret;
> > +
> > + iio_device_get(indio_dev);
> > + iio_buffer_get(buffer);
> > +
> > + return 0;
> > +}
> > +
> > +void iio_device_buffers_put(struct iio_dev *indio_dev)
> > +{
> > + struct iio_buffer *buffer = indio_dev->buffer;
> > +
> > + if (!buffer)
> > + return;
> > +
> > + iio_buffer_put(buffer);
> > +}
> > +
> > +void iio_device_buffers_uninit(struct iio_dev *indio_dev)
> > +{
> > + struct iio_buffer *buffer = indio_dev->buffer;
> > +
> > + if (!buffer)
> > + return;
> > +
> > + cdev_device_del(&buffer->chrdev, &indio_dev->dev);
> > + iio_buffer_put(buffer);
> > + iio_device_put(indio_dev);
> > +}
> > +
> > /**
> > * iio_validate_scan_mask_onehot() - Validates that exactly one channel is
> > selected
> > * @indio_dev: the iio device
> > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-
> > core.c
> > index c8c074602709..2158aeab0bd2 100644
> > --- a/drivers/iio/industrialio-core.c
> > +++ b/drivers/iio/industrialio-core.c
> > @@ -1475,7 +1475,7 @@ static void iio_dev_release(struct device *device)
> > iio_device_unregister_eventset(indio_dev);
> > iio_device_unregister_sysfs(indio_dev);
> >
> > - iio_buffer_put(indio_dev->buffer);
> > + iio_device_buffers_put(indio_dev);
> >
> > ida_simple_remove(&iio_ida, indio_dev->id);
> > kfree(indio_dev);
> > @@ -1610,7 +1610,7 @@ void devm_iio_device_free(struct device *dev, struct
> > iio_dev *iio_dev)
> > EXPORT_SYMBOL_GPL(devm_iio_device_free);
> >
> > /**
> > - * iio_chrdev_open() - chrdev file open for buffer access and ioctls
> > + * iio_chrdev_open() - chrdev file open for event ioctls
> > * @inode: Inode structure for identifying the device in the file system
> > * @filp: File structure for iio device used to keep and later access
> > * private data
> > @@ -1633,7 +1633,7 @@ static int iio_chrdev_open(struct inode *inode, struct
> > file *filp)
> > }
> >
> > /**
> > - * iio_chrdev_release() - chrdev file close buffer access and ioctls
> > + * iio_chrdev_release() - chrdev file close for event ioctls
> > * @inode: Inode structure pointer for the char device
> > * @filp: File structure pointer for the char device
> > *
> > @@ -1649,11 +1649,9 @@ static int iio_chrdev_release(struct inode *inode,
> > struct file *filp)
> > return 0;
> > }
> >
> > -/* Somewhat of a cross file organization violation - ioctls here are
> > actually
> > - * event related */
> > -static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long
> > arg)
> > +long iio_device_event_ioctl(struct iio_dev *indio_dev, struct file *filp,
> > + unsigned int cmd, unsigned long arg)
> > {
> > - struct iio_dev *indio_dev = filp->private_data;
> > int __user *ip = (int __user *)arg;
> > int fd;
> >
> > @@ -1671,16 +1669,15 @@ static long iio_ioctl(struct file *filp, unsigned
> > int cmd, unsigned long arg)
> > return -EINVAL;
> > }
> >
> > -static const struct file_operations iio_buffer_fileops = {
> > - .read = iio_buffer_read_outer_addr,
> > - .release = iio_chrdev_release,
> > - .open = iio_chrdev_open,
> > - .poll = iio_buffer_poll_addr,
> > - .owner = THIS_MODULE,
> > - .llseek = noop_llseek,
> > - .unlocked_ioctl = iio_ioctl,
> > - .compat_ioctl = compat_ptr_ioctl,
> > -};
> > +/* Somewhat of a cross file organization violation - ioctls here are
> > actually
> > + * event related */
> > +static long iio_event_ioctl_wrapper(struct file *filp, unsigned int cmd,
> > + unsigned long arg)
> > +{
> > + struct iio_dev *indio_dev = filp->private_data;
> > +
>
> Hmm. I wonder if we keep a level of indirection in here. So actually call
> something like: 'iio_device_ioctl' in industrialio-core.c and have the
> event registration register a callback with the core. Thus no events and
> nothing is registered so that core function simply returns an error
> - right now I suspect it returns a chardev that is completely useless
> (if no events supported by the device).
>
> > + return iio_device_event_ioctl(indio_dev, filp, cmd, arg);
> > +}
> >
> > static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
> > {
> > @@ -1712,7 +1709,7 @@ static const struct file_operations iio_event_fileops
> > = {
> > .open = iio_chrdev_open,
> > .owner = THIS_MODULE,
> > .llseek = noop_llseek,
> > - .unlocked_ioctl = iio_ioctl,
> > + .unlocked_ioctl = iio_event_ioctl_wrapper,
> > .compat_ioctl = compat_ptr_ioctl,
> > };
> >
> > @@ -1766,16 +1763,21 @@ int __iio_device_register(struct iio_dev *indio_dev,
> > struct module *this_mod)
> > indio_dev->setup_ops == NULL)
> > indio_dev->setup_ops = &noop_ring_setup_ops;
> >
> > - if (indio_dev->buffer)
> > - cdev_init(&indio_dev->chrdev, &iio_buffer_fileops);
> > - else
> > + ret = iio_device_buffers_init(indio_dev, this_mod);
> > + if (ret) {
> > + if (ret != -ENOTSUPP)
> > + goto error_unreg_eventset;
> > +
> > cdev_init(&indio_dev->chrdev, &iio_event_fileops);
> >
> > - indio_dev->chrdev.owner = this_mod;
> > + indio_dev->chrdev.owner = this_mod;
> >
> > - ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
> > - if (ret < 0)
> > - goto error_unreg_eventset;
> > + ret = cdev_device_add(&indio_dev->chrdev, &indio_dev->dev);
> > + if (ret < 0)
> > + goto error_unreg_eventset;
> > +
> > + indio_dev->chrdev_initialized = true;
> > + }
> >
> > return 0;
> >
> > @@ -1797,7 +1799,12 @@ EXPORT_SYMBOL(__iio_device_register);
> > **/
> > void iio_device_unregister(struct iio_dev *indio_dev)
> > {
> > - cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
> > + if (indio_dev->chrdev_initialized)
> > + cdev_device_del(&indio_dev->chrdev, &indio_dev->dev);
> > +
> > + indio_dev->chrdev_initialized = false;
> > +
> > + iio_device_buffers_uninit(indio_dev);
> >
> > mutex_lock(&indio_dev->info_exist_lock);
> >
> > diff --git a/include/linux/iio/buffer_impl.h
> > b/include/linux/iio/buffer_impl.h
> > index 8fb92250a190..b4a55c3f556b 100644
> > --- a/include/linux/iio/buffer_impl.h
> > +++ b/include/linux/iio/buffer_impl.h
> > @@ -1,6 +1,7 @@
> > /* SPDX-License-Identifier: GPL-2.0 */
> > #ifndef _IIO_BUFFER_GENERIC_IMPL_H_
> > #define _IIO_BUFFER_GENERIC_IMPL_H_
> > +#include <linux/cdev.h>
> > #include <linux/sysfs.h>
> > #include <linux/kref.h>
> >
> > @@ -72,6 +73,12 @@ struct iio_buffer {
> > /** @indio_dev: IIO device to which this buffer belongs to. */
> > struct iio_dev *indio_dev;
> >
> > + /** @chrdev: associated character device. */
> > + struct cdev chrdev;
> > +
> > + /** @file_ops_flags: file ops related flags including busy flag. */
> > + unsigned long file_ops_flags;
> > +
> > /** @length: Number of datums in buffer. */
> > unsigned int length;
> >
> > diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> > index e975020abaa6..e93497f483f7 100644
> > --- a/include/linux/iio/iio.h
> > +++ b/include/linux/iio/iio.h
> > @@ -517,6 +517,7 @@ struct iio_buffer_setup_ops {
> > * @setup_ops: [DRIVER] callbacks to call before and after
> > buffer
> > * enable/disable
> > * @chrdev: [INTERN] associated character device
> > + * @chrdev_initialized: [INTERN] true if @chrdev device has been
> > initialized
> > * @groups: [INTERN] attribute groups
> > * @groupcounter: [INTERN] index of next attribute group
> > * @flags: [INTERN] file ops related flags including busy flag.
> > @@ -560,6 +561,7 @@ struct iio_dev {
> > struct mutex info_exist_lock;
> > const struct iio_buffer_setup_ops *setup_ops;
> > struct cdev chrdev;
> > + int chrdev_initialized;
> > #define IIO_MAX_GROUPS 6
> > const struct attribute_group *groups[IIO_MAX_GROUPS + 1];
> > int groupcounter;
