The newbus lock is responsible for protecting newbus internIal structures,
device states and devclass flags. It is necessary to hold it when all
such datas are accessed. For the other operations, softc locking should
ensure enough protection to avoid races.
Newbus lock is automatically held when virtual operations on the device
and bus are invoked when loading the driver or when the suspend/resume
take place. For other 'spourious' operations trying to access/modify
the newbus topology, newbus lock needs to be automatically acquired and
dropped.
For the moment Giant is also acquired in some key point (modules subsystem)
in order to avoid problems before the 8.0 release as module handlers could
make assumptions about it. This Giant locking should go just after
the release happens.
Please keep in mind that the public interface can be expanded in order
to provide more support, if there are really necessities at some point
and also some bugs could arise as long as the patch needs a bit of
further testing.
Bump __FreeBSD_version in order to reflect the newbus lock introduction.
Reviewed by: ed, hps, jhb, imp, mav, scottl
No answer by: ariff, thompsa, yongari
Tested by: pho,
G. Trematerra <giovanni dot trematerra at gmail dot com>,
Brandon Gooch <jamesbrandongooch at gmail dot com>
Sponsored by: Yahoo! Incorporated
Approved by: re (ksmith)
I don't want people to override the mutex when allocating a TTY. It has
to be there, to keep drivers like syscons happy. So I'm creating a
tty_alloc_mutex() which can be used in those cases. tty_alloc_mutex()
should eventually be removed.
The advantage of this approach, is that we can just remove a function,
without breaking the regular API in the future.
to dequeue a packet.
The tx path was trying to ensure that enough Xenbus TX ring slots existed but
it didn't check to see whether the mbuf TX ring slots were also available.
They get freed in xn_txeof() which occurs after transmission, rather than earlier
on in the process. (The same happens under Linux too.)
Due to whatever reason (CPU use, scheduling, memory constraints, whatever) the
mbuf TX ring may not have enough slots free and would allocate slot 0. This is
used as the freelist head pointer to represent "free" mbuf TX ring slots; setting
this to an actual mbuf value rather than an id crashes the code.
This commit introduces some basic code to track the TX mbuf ring use and then
(hopefully!) ensures that enough slots are free in said TX mbuf ring before it
enters the actual work loop.
A few notes:
* Similar logic needs to be introduced to check there are enough actual slots
available in the xenbuf TX ring. There's some logic which is invoked earlier
but it doesn't hard-check against the number of available ring slots.
Its trivial to do; I'll do it in a subsequent commit.
* As I've now commented in the source, it is likely possible to deadlock the
driver under certain conditions where the rings aren't receiving any changes
(which I should enumerate) and thus Xen doesn't send any further software
interrupts. I need to make sure that the timer(s) are running right and
the queues are periodically kicked.
PR: 134926
Slot 0 must always remain "free" and be a pointer to the first free entry in the
mbuf descriptor list. It is thus an error to have code allocate or push slot 0
back into the list.
we, like TCP and UDP, move the checksum calculation
into the IP routines when there is no hardware support
we call into the normal SCTP checksum routine.
The next round of SCTP updates will use
this functionality. Of course the IGB driver needs
a few updates to support the new intel controller set
that actually does SCTP csum offload too.
Reviewed by: gnn, rwatson, kmacy
Inside the kernel, the minor() function was responsible for obtaining
the device minor number of a character device. Because we made device
numbers dynamically allocated and independent of the unit number passed
to make_dev() a long time ago, it was actually a misnomer. If you really
want to obtain the device number, you should use dev2udev().
We already converted all the drivers to use dev2unit() to obtain the
device unit number, which is still used by a lot of drivers. I've
noticed not a single driver passes NULL to dev2unit(). Even if they
would, its behaviour would make little sense. This is why I've removed
the NULL check.
Ths commit removes minor(), minor2unit() and unit2minor() from the
kernel. Because there was a naming collision with uminor(), we can
rename umajor() and uminor() back to major() and minor(). This means
that the makedev(3) manual page also applies to kernel space code now.
I suspect umajor() and uminor() isn't used that often in external code,
but to make it easier for other parties to port their code, I've
increased __FreeBSD_version to 800062.
Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep
Log:
unmask evtchn in bind_{virq, ipi}_to_irq
Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic
The cn_unit and cn_tp fields don't seem to be used anywhere. Some
drivers set them, while others don't. Just remove them, in an attempt to
make our consdev code a little easier to understand.
After I removed all the unit2minor()/minor2unit() calls from the kernel
yesterday, I realised calling minor() everywhere is quite confusing.
Character devices now only have the ability to store a unit number, not
a minor number. Remove the confusion by using dev2unit() everywhere.
This commit could also be considered as a bug fix. A lot of drivers call
minor(), while they should actually be calling dev2unit(). In -CURRENT
this isn't a problem, but it turns out we never had any problem reports
related to that issue in the past. I suspect not many people connect
more than 256 pieces of the same hardware.
Reviewed by: kib
I initially didn't want to integrate the Xen console driver, because it
did not receive any testing. Kip Macy suggested that I'd better check it
in right now, because this is the easiest way for him to test it while
he is working on the Xen import.
Requested by: kmacy
