linux/drivers/usb/core/file.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

265 lines
6.4 KiB
C

/*
* drivers/usb/core/file.c
*
* (C) Copyright Linus Torvalds 1999
* (C) Copyright Johannes Erdfelt 1999-2001
* (C) Copyright Andreas Gal 1999
* (C) Copyright Gregory P. Smith 1999
* (C) Copyright Deti Fliegl 1999 (new USB architecture)
* (C) Copyright Randy Dunlap 2000
* (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
more docs, etc)
* (C) Copyright Yggdrasil Computing, Inc. 2000
* (usb_device_id matching changes by Adam J. Richter)
* (C) Copyright Greg Kroah-Hartman 2002-2003
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/usb.h>
#include "usb.h"
#define MAX_USB_MINORS 256
static const struct file_operations *usb_minors[MAX_USB_MINORS];
static DECLARE_RWSEM(minor_rwsem);
static int usb_open(struct inode * inode, struct file * file)
{
int minor = iminor(inode);
const struct file_operations *c;
int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL;
down_read(&minor_rwsem);
c = usb_minors[minor];
if (!c || !(new_fops = fops_get(c)))
goto done;
old_fops = file->f_op;
file->f_op = new_fops;
/* Curiouser and curiouser... NULL ->open() as "no device" ? */
if (file->f_op->open)
err = file->f_op->open(inode,file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
done:
up_read(&minor_rwsem);
return err;
}
static const struct file_operations usb_fops = {
.owner = THIS_MODULE,
.open = usb_open,
};
static struct usb_class {
struct kref kref;
struct class *class;
} *usb_class;
static char *usb_devnode(struct device *dev, mode_t *mode)
{
struct usb_class_driver *drv;
drv = dev_get_drvdata(dev);
if (!drv || !drv->devnode)
return NULL;
return drv->devnode(dev, mode);
}
static int init_usb_class(void)
{
int result = 0;
if (usb_class != NULL) {
kref_get(&usb_class->kref);
goto exit;
}
usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
if (!usb_class) {
result = -ENOMEM;
goto exit;
}
kref_init(&usb_class->kref);
usb_class->class = class_create(THIS_MODULE, "usb");
if (IS_ERR(usb_class->class)) {
result = IS_ERR(usb_class->class);
printk(KERN_ERR "class_create failed for usb devices\n");
kfree(usb_class);
usb_class = NULL;
goto exit;
}
usb_class->class->devnode = usb_devnode;
exit:
return result;
}
static void release_usb_class(struct kref *kref)
{
/* Ok, we cheat as we know we only have one usb_class */
class_destroy(usb_class->class);
kfree(usb_class);
usb_class = NULL;
}
static void destroy_usb_class(void)
{
if (usb_class)
kref_put(&usb_class->kref, release_usb_class);
}
int usb_major_init(void)
{
int error;
error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
if (error)
printk(KERN_ERR "Unable to get major %d for usb devices\n",
USB_MAJOR);
return error;
}
void usb_major_cleanup(void)
{
unregister_chrdev(USB_MAJOR, "usb");
}
/**
* usb_register_dev - register a USB device, and ask for a minor number
* @intf: pointer to the usb_interface that is being registered
* @class_driver: pointer to the usb_class_driver for this device
*
* This should be called by all USB drivers that use the USB major number.
* If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
* dynamically allocated out of the list of available ones. If it is not
* enabled, the minor number will be based on the next available free minor,
* starting at the class_driver->minor_base.
*
* This function also creates a usb class device in the sysfs tree.
*
* usb_deregister_dev() must be called when the driver is done with
* the minor numbers given out by this function.
*
* Returns -EINVAL if something bad happens with trying to register a
* device, and 0 on success.
*/
int usb_register_dev(struct usb_interface *intf,
struct usb_class_driver *class_driver)
{
int retval = -EINVAL;
int minor_base = class_driver->minor_base;
int minor = 0;
char name[20];
char *temp;
#ifdef CONFIG_USB_DYNAMIC_MINORS
/*
* We don't care what the device tries to start at, we want to start
* at zero to pack the devices into the smallest available space with
* no holes in the minor range.
*/
minor_base = 0;
#endif
intf->minor = -1;
dbg ("looking for a minor, starting at %d", minor_base);
if (class_driver->fops == NULL)
goto exit;
down_write(&minor_rwsem);
for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
if (usb_minors[minor])
continue;
usb_minors[minor] = class_driver->fops;
retval = 0;
break;
}
up_write(&minor_rwsem);
if (retval)
goto exit;
retval = init_usb_class();
if (retval)
goto exit;
intf->minor = minor;
/* create a usb class device for this usb interface */
snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
temp = strrchr(name, '/');
if (temp && (temp[1] != '\0'))
++temp;
else
temp = name;
intf->usb_dev = device_create(usb_class->class, &intf->dev,
MKDEV(USB_MAJOR, minor), class_driver,
"%s", temp);
if (IS_ERR(intf->usb_dev)) {
down_write(&minor_rwsem);
usb_minors[intf->minor] = NULL;
up_write(&minor_rwsem);
retval = PTR_ERR(intf->usb_dev);
}
exit:
return retval;
}
EXPORT_SYMBOL_GPL(usb_register_dev);
/**
* usb_deregister_dev - deregister a USB device's dynamic minor.
* @intf: pointer to the usb_interface that is being deregistered
* @class_driver: pointer to the usb_class_driver for this device
*
* Used in conjunction with usb_register_dev(). This function is called
* when the USB driver is finished with the minor numbers gotten from a
* call to usb_register_dev() (usually when the device is disconnected
* from the system.)
*
* This function also removes the usb class device from the sysfs tree.
*
* This should be called by all drivers that use the USB major number.
*/
void usb_deregister_dev(struct usb_interface *intf,
struct usb_class_driver *class_driver)
{
int minor_base = class_driver->minor_base;
char name[20];
#ifdef CONFIG_USB_DYNAMIC_MINORS
minor_base = 0;
#endif
if (intf->minor == -1)
return;
dbg ("removing %d minor", intf->minor);
down_write(&minor_rwsem);
usb_minors[intf->minor] = NULL;
up_write(&minor_rwsem);
snprintf(name, sizeof(name), class_driver->name, intf->minor - minor_base);
device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
intf->usb_dev = NULL;
intf->minor = -1;
destroy_usb_class();
}
EXPORT_SYMBOL_GPL(usb_deregister_dev);