Immediate problem fixed by the new KPI is the long-standing race
between device creation and assignments to cdev->si_drv1 and
cdev->si_drv2, which allows the window where cdevsw methods might be
called with si_drv1,2 fields not yet set. Devices typically checked
for NULL and returned spurious errors to usermode, and often left some
methods unchecked.
The new function interface is designed to be extensible, which should
allow to add more features to make_dev_s(9) without inventing yet
another name for function to create devices, while maintaining KPI and
even KBI backward-compatibility.
Reviewed by: hps, jhb
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Differential revision: https://reviews.freebsd.org/D4746
A new function prep_devname() sanitizes a device name by removing
leading and redundant sequential slashes. The function returns an error
for names which already exist or are considered invalid.
A new flag MAKEDEV_CHECKNAME for make_dev_p(9) and make_dev_credf(9)
indicates that the caller is prepared to handle an error related to the
device name. An invalid name triggers a panic if the flag is not
specified.
Document the MAKEDEV_CHECKNAME flag in the make_dev(9) manual page.
Idea from: kib
Reviewed by: kib
Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.
Reviewed by: ru
Approved by: philip, ed (mentors)
- Document the minor(3), major(3) and makedev(3) macro's. They also
apply to umajor() and uminor() in the kernel, but hopefully we'll sort
that out one day.
- Briefly dev2unit() inside the make_dev(9) manual page, since this is
now the preferred macro to obtain character device unit numbers inside
the kernel.
- Remove the device_ids(9) manual page. It contains highly inaccurate
information, such as a description of the nonexistent major().
To prevent any further confusion about device minor and unit numbers,
we'd better just refer to device unit numbers. Many people still think
the numbers we show inside devfs have any relation to the numbers passed
to make_dev(9), which is not the case.
Discussed with: kib
cd src/share; find man[1-9] -type f|xargs perl -pi -e 's/[ \t]+$//'
BTW, what editors are the culprits? I'm using vim and it shows
me whitespace at EOL in troff files with a thick blue block...
Reviewed by: Silence from cvs diff -b
MFC after: 7 days
VOP_ABORTOP() went away. at_shutdown() was replaced by undocumented
event handling. Rename remove_dev() here too, and remove the dead
and dead wrong man pages.