global and allocated variables. This strategy is derived from work
originally developed by BSDi for BSD/OS, and applied to FreeBSD by Sam
Leffler:
- Add unp_mtx, a global mutex which will protect all UNIX domain socket
related variables, structures, etc.
- Add UNP_LOCK(), UNP_UNLOCK(), UNP_LOCK_ASSERT() macros.
- Acquire unp_mtx on entering most UNIX domain socket code,
drop/re-acquire around calls into VFS, and release it on return.
- Avoid performing sodupsockaddr() while holding the mutex, so in general
move to allocating storage before acquiring the mutex to copy the data.
- Make a stack copy of the xucred rather than copying out while holding
unp_mtx. Copy the peer credential out after releasing the mutex.
- Add additional assertions of vnode locks following VOP_CREATE().
A few notes:
- Use of an sx lock for the file list mutex may cause problems with regard
to unp_mtx when garbage collection passed file descriptors.
- The locking in unp_pcblist() for sysctl monitoring is correct subject to
the unpcb zone not returning memory for reuse by other subsystems
(consistent with similar existing concerns).
- Sam's version of this change, as with the BSD/OS version, made use of
both a global lock and per-unpcb locks. However, in practice, the
global lock covered all accesses, so I have simplified out the unpcb
locks in the interest of getting this merged faster (reducing the
overhead but not sacrificing granularity in most cases). We will want
to explore possibilities for improving lock granularity in this code in
the future.
Submitted by: sam
Sponsored by: FreeBSD Foundatiuon
Obtained from: BSD/OS 5 snapshot provided by BSDi
present and thus that the PnPBIOS probe should be skipped instead of
having ACPI zero out the PnPBIOStable pointer.
- Make the PnPBIOStable pointer static to i386/i386/bios.c now that that is
the only place it is used.
its primary use is for the FEPS/FAS366 SCSI found in Sun Ultra 1e and 2
machines. Once the pci front-end is ported, this driver can replace the
amd(4) driver.
The code as-is is fairly stable. I've disabled tagged-queueing until I can
figure out a corruption bug related to it. I'm importing it now so that
people with these machines can (finally) stop netbooting and report bugs
before 5.3.
as otherwise the junk it contains may cause uhub_explore to give
up without ever trying to restart the port. This fixes the following
errors I was seeing with a VIA UHCI controller:
uhub0: port error, restarting port 1
uhub0: port error, giving up port 1
(time grows downward)
thread 1 thread 2
------------|------------
dec ref_cnt |
| dec ref_cnt <-- ref_cnt now zero
cmpset |
free all |
return |
|
alloc again,|
reuse prev |
ref_cnt |
| cmpset, read
| already freed
| ref_cnt
------------|------------
This should fix that by performing only a single
atomic test-and-set that will serve to decrement
the ref_cnt, only if it hasn't changed since the
earlier read, otherwise it'll loop and re-read.
This forces ordering of decrements so that truly
the thread which did the LAST decrement is the
one that frees.
This is how atomic-instruction-based refcnting
should probably be handled.
Submitted by: Julian Elischer
internal reference counters, UMA_ZONE_NOFREE. This way, those slabs
(with their ref counts) will be effectively type-stable, then using
a trick like this on the refcount is no longer dangerous:
MEXT_REM_REF(m);
if (atomic_cmpset_int(m->m_ext.ref_cnt, 0, 1)) {
if (m->m_ext.ext_type == EXT_PACKET) {
uma_zfree(zone_pack, m);
return;
} else if (m->m_ext.ext_type == EXT_CLUSTER) {
uma_zfree(zone_clust, m->m_ext.ext_buf);
m->m_ext.ext_buf = NULL;
} else {
(*(m->m_ext.ext_free))(m->m_ext.ext_buf,
m->m_ext.ext_args);
if (m->m_ext.ext_type != EXT_EXTREF)
free(m->m_ext.ref_cnt, M_MBUF);
}
}
uma_zfree(zone_mbuf, m);
Previously, a second thread hitting the above cmpset might
actually read the refcnt AFTER it has already been freed. A very
rare occurance. Now we'll know that it won't be freed, though.
Spotted by: julian, pjd
all of the interface between the driver and the bus. This will enable
us to stop special casing eisa bus attachments in modules and treat them
like we treat all other busses.
In the longer run, we need to eliminate much (all?) of these interfaces
and switch to using the standard bus_alloc_resource(), but that's not
done right now.
# I've not updated the modules to include eisa, etc, just yet
Tested on: Compaq Proliant 3000/333 purchased for eisa work
mode. The 5704 apparently has some s00p3r s33kr1t registers for setting
the advertisement of pause frame ability (i.e flow control) when in
autoneg mode. If we don't set these registers correctly, we may not
be able to negotiate a proper link with some switches. (Symptom is that
the NIC reports the link as up (PCS synched) but no traffic can be
exchanged.)
PR: kern/67598
Add two new functions: ttyref() and ttyrel(). ttymalloc() creates a struct
tty with a reference count of one. when ttyrel sees the count go to zero,
struct tty is freed.
Hold references for open ttys and for ttys which are controlling terminal
for sessions.
Until drivers start using ttyrel(), this commit will make no difference.
different cards that matched vendor/id, but weren't wi cards. This is
because the vendor foolishly didn't have unique product ids. Symbol
has a serial card that would otherwise match the wi driver, for
example...
Taken from a patch for xe posted by: Carlos Velasco
recursive entering of the socket code from the routing code:
- Modify rt_dispatch() to bundle up the sockaddr family, if any,
associated with a pending mbuf to dispatch to routing sockets, in
an m_tag on the mbuf.
- Allocate NETISR_ROUTE for use by routing sockets.
- Introduce rtsintrq, an ifqueue to be used by the netisr, and
introduce rts_input(), a function to unbundle the tagged sockaddr
and inject the mbuf and address into raw_input(), which previously
occurred in rt_dispatch().
- Introduce rts_init() to initialize rtsintrq, its mutex, and
register the netisr. Perform this at the same point in system
initialization as setup of the domains.
This change introduces asynchrony between the generation of a
pending routing socket message and delivery to sockets for use
by userspace. It avoids socket->routing->rtsock->socket use and
helps to avoid lock order reversals between the routing code and
socket code (in particular, raw socket control blocks), as route
locks are held over calls to rt_dispatch().
Reviewed by: "George V.Neville-Neil" <gnn@neville-neil.com>
Conceptual head nod by: sam
pmap_extract() already does it.
In pmap_enter(), opa has already been masked so don't do it again.
Wrap a long line (recent transgression).
Use trunc_page() in pmap_mapdev() instead of anding with PG_FRAME, since
that is what we really meant.
Submitted by: alc (first item)
