The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:
- Improved driver model:
The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.
If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.
- Improved hotplugging:
With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).
The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.
- Improved performance:
One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.
Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.
Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan
needed to promote cdev to cdev_priv, the si_priv pointer was followed.
Use member2struct() to calculate address of the wrapping cdev_priv.
Rename si_priv to __si_reserved.
Tested by: pho
Reviewed by: ed
MFC after: 2 weeks
Even though I ran a `make universe' to see whether the changes to the
device minor number macro's broke the build, I was not expecting `make
universe' to silently continue if build errors occured, thus causing me
to overlook the build error.
Approved by: philip (mentor)
Pointyhat to: me
similar to _WANT_UCRED and _WANT_PRISON and seems to be much nicer than
defining _KERNEL.
It is also needed for my sys/refcount.h change going in soon.
the vnode pointer is not NULL. This avoids spurious warnings in fstat -v
output for kernel processes.
MFC after: 1 week
PR: amd64/123456
Submitted by: KOIE Hidetaka | hide koie.org
src/cddl and src/sys/cddl directories per the core@ decision following
the license review.
This change modifies the affected Makefiles to reference the sources
in their new location.
the open file-listing. It is added as a separate source file, so it can
respect WITH_/WITHOUT_CDDL as compile-flags.
- The warnlevel of the Makefile was decreased to quell solaris #pragma
warnings.
- Expect that fstat(1) doesn't work with kernel compiled with
DEBUG_VFS_LOCKS/DEBUG_LOCKS for now.
Approved by: pjd (mentor)
caused fstat to produce duplicated output for threaded processes. Instead
use KERN_PROC_PROC to get just one kinfo_proc per process.
MFC After: 2 weeks
this by accessing the cdev_priv element of the cdev structure. Looking
forward we need a better way to handle this, as this structure shouldn't
be frobbed by userspace.
Submitted by: Doug Steinwand
PR: bin/88203
MFC after: 1 week
Discussed with: phk
cdev structure, returns the device name associated with it through
the __si_namebuf member. This un-breaks the processing of devices.
This is a RELENG_6 candidate.
Reviewed by: phk
Nowadays, f_data points to the vnode only if the underlying filesystem
doesn't use it for other purposes (devfs uses it to store the cdev,
for example).
Found by: csjp
Reviewed by: csjp
Approved by: phk, wes, grehan (mentor)
MFC after: 1 week
2) Use %p to print a pointer.
3) Use longs for fileids and ino to avoid comparing signed and unsigned.
4) Make the KVM_READ macro a little more cranky.
5) Set WARNS while I'm here.
The big lines are:
NODEV -> NULL
NOUDEV -> NODEV
udev_t -> dev_t
udev2dev() -> findcdev()
Various minor adjustments including handling of userland access to kernel
space struct cdev etc.
