Clists were originally used by the TTY layer as a text buffer interface.
The advantage of clists were that it would allocate a small set of
additional buffers that could be shared between TTYs when needed. In
the modern days we can just allocate some more KBs of memory to keep the
TTYs satisfied. The global cfreelist also requires synchronisation,
which may not be useful when trying to improve scalability.
The MPSAFE TTY layer uses its own text buffers (ttyinq and ttyoutq). We
had a small amount of drivers in the tree that still uses clists, like
the old USB stack and some keyboard drivers. With the old USB stack gone
and the keyboard drivers changed to use a circular buffer, we can safely
remove clists from the kernel.
Some time ago Tom Rhodes sent me an email that he was willing to perform
various cleanups to the window(1) source code. After some discussion, we
both decided the best thing to do, was to move window(1) to the ports
tree. The application isn't used a lot nowadays, mainly because it has
been superseeded by screen, tmux, etc.
A couple of hours ago Tom committed window(1) to ports (misc/window), so
I'm removing it from the tree. I don't think people will really miss it,
but I'm describing the change in UPDATING anyway.
Discussed with: trhodes, pav, kib
Approved by: re
Last year I added SLIST_REMOVE_NEXT and STAILQ_REMOVE_NEXT, to remove
entries behind an element in the list, using O(1) time. I recently
discovered NetBSD also has a similar macro, called SLIST_REMOVE_AFTER.
In my opinion this approach is a lot better:
- It doesn't have the unused first argument of the list pointer. I added
this, mainly because OpenBSD also had it.
- The _AFTER suffix makes a lot more sense, because it is related to
SLIST_INSERT_AFTER. _NEXT is only used to iterate through the list.
The reason why I want to rename this now, is to make sure we don't
release a major version with the badly named macros.
Not only did these two drivers depend on IFF_NEEDSGIANT, they were
broken 7 months ago during the MPSAFE TTY import. if_ppp(4) has been
replaced by ppp(8). There is no replacement for if_sl(4).
If we see regressions in for example the ports tree, we should just use
__FreeBSD_version 800045 to check whether if_ppp(4) and if_sl(4) are
present. Version 800045 is used to denote the import of MPSAFE TTY.
Discussed with: rwatson, but also rwatson's IFF_NEEDSGIANT emails on the
lists.
driver in Linux 2.6. uscanner was just a simple wrapper around a fifo and
contained no logic, the default interface is now libusb (supported by sane).
Reviewed by: HPS
ports tree so that programs use libusb from the base by default. Thanks to
Stanislav Sedov for sorting out the ports build.
Bump __FreeBSD_version to 800069
Help and testing by: stas
The function pow() in libmp(3) clashes with pow(3) in libm. We could
rename this single function, but we can just take the same approach as
the Solaris folks did, which is to prefix all function names with mp_.
libmp(3) isn't really popular nowadays. I suspect not a single
application in ports depends on it. There's still a chance, so I've
increased the SHLIB_MAJOR and __FreeBSD_version.
Reviewed by: deischen, rdivacky
- 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().
years by the priv_check(9) interface and just very few places are left.
Note that compatibility stub with older FreeBSD version
(all above the 8 limit though) are left in order to reduce diffs against
old versions. It is responsibility of the maintainers for any module, if
they think it is the case, to axe out such cases.
This patch breaks KPI so __FreeBSD_version will be bumped into a later
commit.
This patch needs to be credited 50-50 with rwatson@ as he found time to
explain me how the priv_check() works in detail and to review patches.
Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
Reviewed by: rwatson
Before we had a posix_openpt() that allocated PTY's with proper
permissions in place, we used this set-uid utility to change the
ownership of PTY slave devices to the real user ID of the process. This
utility was used to implement grantpt().
In my first designs of the MPSAFE TTY layer, I replaced this by adding
an ioctl() called TIOCGRANTPT, which was used to change the ownership.
I left the pt_chown utility, because older C libraries needed it to work
properly.
After some discussions back in June I changed the PTY code to set
permissions properly upon creation. Fortunately the previous grantpt()
implementation changed permissions by hand when pt_chown is not
installed, which always succeeds. This means grantpt() still works
properly, even though the set-uid utility is missing.
I've done tests with FreeBSD 5.2.1, FreeBSD 6.3 and FreeBSD 7.0 jails.
All of them still work if I remove pt_chown.
Reviewed by: philip (ex-mentor)
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
When I turned sgtty into a binary-only interface (last month), I added
this explicit #error to the header file, to make sure nobody forgot to
remove the header file after updating world.
I think it is now a good moment to remove this header file.
Approved by: philip (mentor)
MPSAFE patches on current@ and stable@. This driver also has a fundamental
issue in that it sleeps when sending commands to the card including in the
if_init/if_start routines (which can be called from interrupt context). As
such, the driver shouldn't be working reliably even on 4.x.
