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SubjectRe: [PATCH 0/7] parport: Use generic kernel logging styles
From
Date
On Sat, 2020-02-29 at 08:40 -0800, Randy Dunlap wrote:
> On 2/28/20 12:32 AM, Joe Perches wrote:
> > Well, if the parport logging is getting some generic fixing,
> > here's some more generic logging fixing...
> >
> > Joe Perches (7):
> > parport: Convert printk(KERN_<LEVEL> to pr_<level>(
> > parport: Use more comon logging styles
> > parport: daisy: Convert DPRINTK to pr_debug
> > parport_amiga: Convert DPRINTK to pr_debug
> > parport_mfc3: Convert DPRINTK to pr_debug
> > parport_pc: Convert DPRINTK to pr_debug
> > parport: Standardize use of printmode
>
> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

btw: Sudip

After this recent daisy change:
---------------------------------------------------------------------

commit 60f8a59ddcdc7fb7c17180ba10d9c49bc91156c7
Author: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Date: Wed Oct 16 15:45:40 2019 +0100

parport: daisy: use new parport device model

Modify parport daisy driver to use the new parallel port device model.

Last attempt was '1aec4211204d ("parport: daisy: use new parport device
model")' which failed as daisy was also trying to load the low level
driver and that resulted in a deadlock.

---------------------------------------------------------------------

parport_register_device is no longer in use and
parport_register_dev_model is used instead.

Documentation/driver-api/parport-lowlevel.rst
should be updated and the various comments can
be updated or deleted.

$ git grep -w parport_register_device
Documentation/driver-api/parport-lowlevel.rst: parport_register_device
Documentation/driver-api/parport-lowlevel.rst: dev[count++] = parport_register_device (...);
Documentation/driver-api/parport-lowlevel.rst:parport_unregister_driver, parport_register_device, parport_enumerate
Documentation/driver-api/parport-lowlevel.rst:parport_register_device - register to use a port
Documentation/driver-api/parport-lowlevel.rst: struct pardevice *parport_register_device(struct parport *port,
Documentation/driver-api/parport-lowlevel.rst: private->dev = parport_register_device (port, "toaster", preempt,
Documentation/driver-api/parport-lowlevel.rst:This function is the opposite of parport_register_device. After using
Documentation/driver-api/parport-lowlevel.rst:This is like parport_register_device but takes a device number instead
Documentation/driver-api/parport-lowlevel.rst:See parport_register_device. If no device is associated with devnum,
Documentation/driver-api/parport-lowlevel.rst:parport_register_device
drivers/parport/daisy.c: * This function is similar to parport_register_device(), except
drivers/parport/daisy.c: * parport_register_device(). The return value is the same as
drivers/parport/daisy.c: * for parport_register_device().
drivers/parport/daisy.c: * parport_register_device().
drivers/parport/share.c: * parport_register_device() on that port will do this for you.
drivers/parport/share.c: * parport_register_device - register a device on a parallel port
drivers/parport/share.c:parport_register_device(struct parport *port, const char *name,
drivers/parport/share.c:EXPORT_SYMBOL(parport_register_device);
drivers/parport/share.c: * This undoes the effect of parport_register_device().
include/linux/parport.h:/* parport_register_device declares that a device is connected to a
include/linux/parport.h:struct pardevice *parport_register_device(struct parport *port,
scripts/kernel-doc: # - parport_register_device (function pointer parameters)

Maybe something like this is necessary:
(it will need to be edited, I just deleted the references)
---
Documentation/driver-api/parport-lowlevel.rst | 72 ++--------
drivers/auxdisplay/panel.c | 2 +-
drivers/parport/daisy.c | 10 +-
drivers/parport/share.c | 197 +-------------------------
include/linux/parport.h | 12 --
scripts/kernel-doc | 1 -
6 files changed, 17 insertions(+), 277 deletions(-)

diff --git a/Documentation/driver-api/parport-lowlevel.rst b/Documentation/driver-api/parport-lowlevel.rst
index 0633d70..42b1c87 100644
--- a/Documentation/driver-api/parport-lowlevel.rst
+++ b/Documentation/driver-api/parport-lowlevel.rst
@@ -10,7 +10,7 @@ Global functions::
parport_register_driver
parport_unregister_driver
parport_enumerate
- parport_register_device
+ parport_register_dev_model
parport_unregister_device
parport_claim
parport_claim_or_block
@@ -205,7 +205,7 @@ EXAMPLE
{
...
private = kmalloc (...);
- dev[count++] = parport_register_device (...);
+ dev[count++] = parport_register_dev_model (...);
...
}

@@ -235,7 +235,7 @@ EXAMPLE
SEE ALSO
^^^^^^^^

-parport_unregister_driver, parport_register_device, parport_enumerate
+parport_unregister_driver, parport_enumerate



@@ -354,7 +354,7 @@ parport_register_driver, parport_unregister_driver



-parport_register_device - register to use a port
+parport_register_dev_model - register to use a port
------------------------------------------------

SYNOPSIS
@@ -368,60 +368,21 @@ SYNOPSIS
typedef void (*wakeup_func) (void *handle);
typedef int (*irq_func) (int irq, void *handle, struct pt_regs *);

- struct pardevice *parport_register_device(struct parport *port,
- const char *name,
- preempt_func preempt,
- wakeup_func wakeup,
- irq_func irq,
- int flags,
- void *handle);
+ struct pardevice *parport_register_dev_model(struct parport *port,
+ const char *name,
+ const struct pardev_cb *par_dev_cb,
+ int cnt);

DESCRIPTION
^^^^^^^^^^^

Use this function to register your device driver on a parallel port
-(``port``). Once you have done that, you will be able to use
-parport_claim and parport_release in order to use the port.
+(``port``).

The (``name``) argument is the name of the device that appears in /proc
filesystem. The string must be valid for the whole lifetime of the
device (until parport_unregister_device is called).

-This function will register three callbacks into your driver:
-``preempt``, ``wakeup`` and ``irq``. Each of these may be NULL in order to
-indicate that you do not want a callback.
-
-When the ``preempt`` function is called, it is because another driver
-wishes to use the parallel port. The ``preempt`` function should return
-non-zero if the parallel port cannot be released yet -- if zero is
-returned, the port is lost to another driver and the port must be
-re-claimed before use.
-
-The ``wakeup`` function is called once another driver has released the
-port and no other driver has yet claimed it. You can claim the
-parallel port from within the ``wakeup`` function (in which case the
-claim is guaranteed to succeed), or choose not to if you don't need it
-now.
-
-If an interrupt occurs on the parallel port your driver has claimed,
-the ``irq`` function will be called. (Write something about shared
-interrupts here.)
-
-The ``handle`` is a pointer to driver-specific data, and is passed to
-the callback functions.
-
-``flags`` may be a bitwise combination of the following flags:
-
- ===================== =================================================
- Flag Meaning
- ===================== =================================================
- PARPORT_DEV_EXCL The device cannot share the parallel port at all.
- Use this only when absolutely necessary.
- ===================== =================================================
-
-The typedefs are not actually defined -- they are only shown in order
-to make the function prototype more readable.
-
The visible parts of the returned ``struct pardevice`` are::

struct pardevice {
@@ -468,9 +429,7 @@ EXAMPLE

static int toaster_detect (struct toaster *private, struct parport *port)
{
- private->dev = parport_register_device (port, "toaster", preempt,
- wakeup, NULL, 0,
- private);
+ private->dev = parport_register_dev_model(port, "toaster", ...);
if (!private->dev)
/* Couldn't register with parport. */
return -EIO;
@@ -511,7 +470,7 @@ SYNPOPSIS
DESCRIPTION
^^^^^^^^^^^

-This function is the opposite of parport_register_device. After using
+This function is the opposite of parport_register_dev_model. After using
parport_unregister_device, ``dev`` is no longer a valid device handle.

You should not unregister a device that is currently claimed, although
@@ -879,20 +838,15 @@ SYNOPSIS
DESCRIPTION
^^^^^^^^^^^

-This is like parport_register_device but takes a device number instead
+This is like parport_register_dev_model but takes a device number instead
of a pointer to a struct parport.

RETURN VALUE
^^^^^^^^^^^^

-See parport_register_device. If no device is associated with devnum,
+See parport_register_dev_model. If no device is associated with devnum,
NULL is returned.

-SEE ALSO
-^^^^^^^^
-
-parport_register_device
-


parport_close - unregister device for particular device number
diff --git a/drivers/auxdisplay/panel.c b/drivers/auxdisplay/panel.c
index 85965953..cf4b12 100644
--- a/drivers/auxdisplay/panel.c
+++ b/drivers/auxdisplay/panel.c
@@ -1589,7 +1589,7 @@ static void panel_attach(struct parport *port)

pprt = parport_register_dev_model(port, "panel", &panel_cb, 0);
if (!pprt) {
- pr_err("%s: port->number=%d parport=%d, parport_register_device() failed\n",
+ pr_err("%s: port->number=%d parport=%d, parport_register_dev_model() failed\n",
__func__, port->number, parport);
return;
}
diff --git a/drivers/parport/daisy.c b/drivers/parport/daisy.c
index 6d78ec..7dc641 100644
--- a/drivers/parport/daisy.c
+++ b/drivers/parport/daisy.c
@@ -228,14 +228,6 @@ void parport_daisy_fini(struct parport *port)
* parport_open - find a device by canonical device number
* @devnum: canonical device number
* @name: name to associate with the device
- *
- * This function is similar to parport_register_device(), except
- * that it locates a device by its number rather than by the port
- * it is attached to.
- *
- * All parameters except for @devnum are the same as for
- * parport_register_device(). The return value is the same as
- * for parport_register_device().
**/

struct pardevice *parport_open(int devnum, const char *name)
@@ -289,7 +281,7 @@ struct pardevice *parport_open(int devnum, const char *name)
* @dev: device to close
*
* This is to parport_open() as parport_unregister_device() is to
- * parport_register_device().
+ * parport_register_dev_model().
**/

void parport_close(struct pardevice *dev)
diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 3169fee..484723 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -262,8 +262,7 @@ static int port_detect(struct device *dev, void *dev_drv)
* The driver's attach() function may block. The port that
* attach() is given will be valid for the duration of the
* callback, but if the driver wants to take a copy of the
- * pointer it must call parport_get_port() to do so. Calling
- * parport_register_device() on that port will do this for you.
+ * pointer it must call parport_get_port() to do so.
*
* The driver's detach() function may block. The port that
* detach() is given will be valid for the duration of the
@@ -641,198 +640,6 @@ void parport_remove_port(struct parport *port)
}
EXPORT_SYMBOL(parport_remove_port);

-/**
- * parport_register_device - register a device on a parallel port
- * @port: port to which the device is attached
- * @name: a name to refer to the device
- * @pf: preemption callback
- * @kf: kick callback (wake-up)
- * @irq_func: interrupt handler
- * @flags: registration flags
- * @handle: data for callback functions
- *
- * This function, called by parallel port device drivers,
- * declares that a device is connected to a port, and tells the
- * system all it needs to know.
- *
- * The @name is allocated by the caller and must not be
- * deallocated until the caller calls @parport_unregister_device
- * for that device.
- *
- * The preemption callback function, @pf, is called when this
- * device driver has claimed access to the port but another
- * device driver wants to use it. It is given @handle as its
- * parameter, and should return zero if it is willing for the
- * system to release the port to another driver on its behalf.
- * If it wants to keep control of the port it should return
- * non-zero, and no action will be taken. It is good manners for
- * the driver to try to release the port at the earliest
- * opportunity after its preemption callback rejects a preemption
- * attempt. Note that if a preemption callback is happy for
- * preemption to go ahead, there is no need to release the port;
- * it is done automatically. This function may not block, as it
- * may be called from interrupt context. If the device driver
- * does not support preemption, @pf can be %NULL.
- *
- * The wake-up ("kick") callback function, @kf, is called when
- * the port is available to be claimed for exclusive access; that
- * is, parport_claim() is guaranteed to succeed when called from
- * inside the wake-up callback function. If the driver wants to
- * claim the port it should do so; otherwise, it need not take
- * any action. This function may not block, as it may be called
- * from interrupt context. If the device driver does not want to
- * be explicitly invited to claim the port in this way, @kf can
- * be %NULL.
- *
- * The interrupt handler, @irq_func, is called when an interrupt
- * arrives from the parallel port. Note that if a device driver
- * wants to use interrupts it should use parport_enable_irq(),
- * and can also check the irq member of the parport structure
- * representing the port.
- *
- * The parallel port (lowlevel) driver is the one that has called
- * request_irq() and whose interrupt handler is called first.
- * This handler does whatever needs to be done to the hardware to
- * acknowledge the interrupt (for PC-style ports there is nothing
- * special to be done). It then tells the IEEE 1284 code about
- * the interrupt, which may involve reacting to an IEEE 1284
- * event depending on the current IEEE 1284 phase. After this,
- * it calls @irq_func. Needless to say, @irq_func will be called
- * from interrupt context, and may not block.
- *
- * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
- * so should only be used when sharing the port with other device
- * drivers is impossible and would lead to incorrect behaviour.
- * Use it sparingly! Normally, @flags will be zero.
- *
- * This function returns a pointer to a structure that represents
- * the device on the port, or %NULL if there is not enough memory
- * to allocate space for that structure.
- **/
-
-struct pardevice *
-parport_register_device(struct parport *port, const char *name,
- int (*pf)(void *), void (*kf)(void *),
- void (*irq_func)(void *),
- int flags, void *handle)
-{
- struct pardevice *tmp;
-
- if (port->physport->flags & PARPORT_FLAG_EXCL) {
- /* An exclusive device is registered. */
- printk(KERN_DEBUG "%s: no more devices allowed\n", port->name);
- return NULL;
- }
-
- if (flags & PARPORT_DEV_LURK) {
- if (!pf || !kf) {
- pr_info("%s: refused to register lurking device (%s) without callbacks\n",
- port->name, name);
- return NULL;
- }
- }
-
- if (flags & PARPORT_DEV_EXCL) {
- if (port->physport->devices) {
- /*
- * If a device is already registered and this new
- * device wants exclusive access, then no need to
- * continue as we can not grant exclusive access to
- * this device.
- */
- pr_err("%s: cannot grant exclusive access for device %s\n",
- port->name, name);
- return NULL;
- }
- }
-
- /*
- * We up our own module reference count, and that of the port
- * on which a device is to be registered, to ensure that
- * neither of us gets unloaded while we sleep in (e.g.)
- * kmalloc.
- */
- if (!try_module_get(port->ops->owner))
- return NULL;
-
- parport_get_port(port);
-
- tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
- if (!tmp)
- goto out;
-
- tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
- if (!tmp->state)
- goto out_free_pardevice;
-
- tmp->name = name;
- tmp->port = port;
- tmp->daisy = -1;
- tmp->preempt = pf;
- tmp->wakeup = kf;
- tmp->private = handle;
- tmp->flags = flags;
- tmp->irq_func = irq_func;
- tmp->waiting = 0;
- tmp->timeout = 5 * HZ;
- tmp->devmodel = false;
-
- /* Chain this onto the list */
- tmp->prev = NULL;
- /*
- * This function must not run from an irq handler so we don' t need
- * to clear irq on the local CPU. -arca
- */
- spin_lock(&port->physport->pardevice_lock);
-
- if (flags & PARPORT_DEV_EXCL) {
- if (port->physport->devices) {
- spin_unlock(&port->physport->pardevice_lock);
- printk(KERN_DEBUG "%s: cannot grant exclusive access for device %s\n",
- port->name, name);
- goto out_free_all;
- }
- port->flags |= PARPORT_FLAG_EXCL;
- }
-
- tmp->next = port->physport->devices;
- wmb(); /*
- * Make sure that tmp->next is written before it's
- * added to the list; see comments marked 'no locking
- * required'
- */
- if (port->physport->devices)
- port->physport->devices->prev = tmp;
- port->physport->devices = tmp;
- spin_unlock(&port->physport->pardevice_lock);
-
- init_waitqueue_head(&tmp->wait_q);
- tmp->timeslice = parport_default_timeslice;
- tmp->waitnext = tmp->waitprev = NULL;
-
- /*
- * This has to be run as last thing since init_state may need other
- * pardevice fields. -arca
- */
- port->ops->init_state(tmp, tmp->state);
- if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
- port->proc_device = tmp;
- parport_device_proc_register(tmp);
- }
- return tmp;
-
- out_free_all:
- kfree(tmp->state);
- out_free_pardevice:
- kfree(tmp);
- out:
- parport_put_port(port);
- module_put(port->ops->owner);
-
- return NULL;
-}
-EXPORT_SYMBOL(parport_register_device);
-
static void free_pardevice(struct device *dev)
{
struct pardevice *par_dev = to_pardevice(dev);
@@ -986,7 +793,7 @@ EXPORT_SYMBOL(parport_register_dev_model);
* parport_unregister_device - deregister a device on a parallel port
* @dev: pointer to structure representing device
*
- * This undoes the effect of parport_register_device().
+ * This undoes the effect of parport_register_dev_model().
**/

void parport_unregister_device(struct pardevice *dev)
diff --git a/include/linux/parport.h b/include/linux/parport.h
index 13932ce..b7a5d06 100644
--- a/include/linux/parport.h
+++ b/include/linux/parport.h
@@ -325,18 +325,6 @@ struct pardev_cb {
unsigned int flags;
};

-/* parport_register_device declares that a device is connected to a
- port, and tells the kernel all it needs to know.
- - pf is the preemption function (may be NULL for no callback)
- - kf is the wake-up function (may be NULL for no callback)
- - irq_func is the interrupt handler (may be NULL for no interrupts)
- - handle is a user pointer that gets handed to callback functions. */
-struct pardevice *parport_register_device(struct parport *port,
- const char *name,
- int (*pf)(void *), void (*kf)(void *),
- void (*irq_func)(void *),
- int flags, void *handle);
-
struct pardevice *
parport_register_dev_model(struct parport *port, const char *name,
const struct pardev_cb *par_dev_cb, int cnt);
diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index f2d73f..acd0e3 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -1607,7 +1607,6 @@ sub dump_function($$) {
#
# If you mess with these regexps, it's a good idea to check that
# the following functions' documentation still comes out right:
- # - parport_register_device (function pointer parameters)
# - atomic_set (macro)
# - pci_match_device, __copy_to_user (long return type)

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