lock is obtained before the write count is increased during open() and the
lock is released after the write count is decreased during close().
The first change closes a race where an open() that will block with O_SHLOCK
or O_EXLOCK can increase the write count while it waits. If the process
holding the current lock on the file then tries to call exec() on the file
it has locked, it can fail with ETXTBUSY even though the advisory lock is
preventing other threads from succesfully completeing a writable open().
The second change closes a race where a read-only open() with O_SHLOCK or
O_EXLOCK may return successfully while the write count is non-zero due to
another descriptor that had the advisory lock and was blocking the open()
still being in the process of closing. If the process that completed the
open() then attempts to call exec() on the file it locked, it can fail with
ETXTBUSY even though the other process that held a write lock has closed
the file and released the lock.
Reviewed by: kib
MFC after: 1 month
code is called and remove it from ath_buf_set_rate().
For the legacy (non-11n API) TX routines, ath_hal_filltxdesc() takes care
of setting up the intermediary and final descriptors right, complete
with copying the rate control info into the final descriptor so the
rate modules can grab it.
The 11n version doesn't do this - ath_hal_chaintxdesc() doesn't
copy the rate control bits over, nor does it clear isaggr/moreaggr/
pad delimiters. So the call to setuplasttxdesc() is needed here.
So:
* legacy NICs - never call the 11n rate control stuff, so filltxdesc
copies the rate control info right;
* 11n NICs transmitting legacy or 11n non-aggregate frames -
ath_hal_set11nratescenario() is called to setup rate control and
then ath_hal_filltxdesc() chains them together - so the rate control
info is right;
* 11n aggregate frames - set11nratescenario() is called, then
ath_hal_chaintxdesc() is called to chain a list of aggregate and subframes
together. This requires a call to ath_hal_setuplasttxdesc() to complete
things.
Tested:
* AR9280 in station mode
TODO:
* I really should make sure that the descriptor contents get blanked
out correctly or garbage left over from aggregate frames may show
up in non-aggregate frames, leading to badness.
functions, for both legacy and 802.11n.
This will simplify supporting the EDMA chipsets as these two descriptor
setup functions can just be overridden in their entirety, hiding all of
the subtle differences in setting things up.
It's not a permanent solution, as eventually the AR5416 HAL should grow
similar versions of the 11n descriptor functions and then those can be
used.
TODO:
* Push the "clr11naggr" call into the legacy setds, just to ensure
that retried frames don't end up with the aggregate bits set
inappropriately;
* Remove the "setlasttxdesc" call from the 11n TX path and push it
into setds_11n.
* Ensure that setds_11n will work correctly for non-aggregate frames;
* .. and then when it does, just unconditionally call "setds_11n" for
11n NICs and "setds" for non-11n NICs.
For C1 and C2 states use cpu_ticks() to measure sleep time instead of much
slower ACPI timer. We can't do it for C3, as TSC may stop there. But it is
less important there as wake up latency is high any way.
For C1 and C2 states do not check/clear bus mastering activity status, as
it is important only for C3. As side effect it can make CPU enter C2 instead
of C3 if last BM activity was two sleeps back (unlike one before), but
that may be even good because of collecting more statistics. Premature BM
wakeup from C3, entered because of overestimation, can easily be worse then
entering C2 from both performance and power consumption points of view.
Together on dual Xeon E5645 system on sequential 512 bytes read test this
change makes cpu_idle_acpi() as fast as simplest cpu_idle_hlt() and only
few percents slower then cpu_idle_mwait(), while deeper states are still
actively used during idle periods.
To help with diagnostics, add C-state type into dev.cpu.X.cx_supported.
Sponsored by: iXsystems, Inc.
* Earlier we compared two not equal metrics, one was what we recevied
in the 'new PREQ' while the other was what we already have saved which
was 'old PREQ' + link metric for the last hop;
* Fixed by adding 'new PREQ' + link metric for the last hop in a
temporary variable;
For description of the test scripts refer to projects/net80211_testsuite/wtap.
* Test 007 showed a bug in intermediate PREP for a proxy entry. Resolved;
* Test 002 showed a bug in the Addressing Mode flag for a PREQ. Resolved;
* Changed KASSERT to be debug printf (DWTAP_PRINTF). If state is not
IEEE80211_S_RUN we return without scheduling a new callout;
* When net80211 stack changes state to IEEE802_11_INIT we stop the
beacon callout task;
I found 8.3 is a history BSD version using socket to implement FIFO
pipe, it uses per-file seqcount to compare with writer generation
stored in per-pipe object. The concept is after all writers are gone,
the pipe enters next generation, all old readers have not closed the
pipe should get the indication that the pipe is disconnected, result
is they should get EPIPE, SIGPIPE or get POLLHUP in poll().
But newcomer should not know that previous writters were gone, it
should treat it as a fresh session.
I am trying to bring back FIFO pipe to history behavior. It is still
unclear that if single EOF flag can represent SBS_CANTSENDMORE and
SBS_CANTRCVMORE which socket-based version is using, but I have run
the poll regression test in tool directory, output is same as the one
on 8.3-STABLE now.
I think the output "not ok 18 FIFO state 6b: poll result 0 expected 1.
expected POLLHUP; got 0" might be bogus, because newcomer should not
know that old writers were gone. I got the same behavior on Linux.
Our implementation always return POLLIN for disconnected pipe even it
should return POLLHUP, but I think it is not wise to remove POLLIN for
compatible reason, this is our history behavior.
Regression test: /usr/src/tools/regression/poll
These (and a few others) will differ based on the underlying DMA
implementation.
For the EDMA NICs, simply stub them out in a fashion which will let
me focus on implementing the necessary descriptor API changes.
flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal
state, when a FIFO peer reader closes the pipe, it wants to notify the writer,
it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer
never noticed the case, but in general, the writer should return from the
syscall with EPIPE error code and may get SIGPIPE signal. Setting the
PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the
problem too. This bug is found by PR/170203.
Another bug in FIFO pipe code is when peer closes the pipe, another end which
is being blocked in select() or poll() is not notified, it missed to call
pipeselwakeup().
Third problem is found in poll regression test, the existing code can not
pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the
problem, I still need to study more to find the cause.
PR: 170203
Tested by: Garrett Copper < yanegomi at gmail dot com >
ktr(4), was constrained to be a power of two. Remove this constraint and
update sys/conf/NOTES accordingly.
Reviewed by: jhb
Approved by: gnn (mentor)
Sponsored by: Google Summer of Code 2012
for an uninitialized variable.
unused parameters and variables are annotated with
(void)foo; /* UNUSED */
instead of __unused, because this code needs to build
also on linux and windows.
'encapsulating interface' used with IPsec and has nothing to do with
storage 'enclosure' services.
MFC after: 3 days
Noticed while: debugging why enc(4) is no longer automatically created
This change triggered interesting foot shooting condition in GEOM when
RW access to root partition by fsck spoils VFS geom there, which has it
opened RO at the same time. Seems spoiling concept needs some rework.
When waiting for child processes using "wait" or if "set -T" is in effect, a
signal interrupts the wait. Make sure there is no window where the signal
handler may be invoked (setting a flag) just before going to sleep.
There is a similar race condition in the shell language, but scripts can
avoid it by exiting from the trap handler or enforcing synchronization using
a fifo.
If SIGCHLD is not trapped, a signal handler must be installed for it. Only
install this handler for the duration of the wait to avoid triggering
unexpected [EINTR] errors elsewhere.
Note that for some reason only SIGINT and SIGQUIT interrupt a "wait"
command. This remains the case.
a tinderbox myself and caught the error.
Change to isp_send_cmd needs a final ecmd argument.
Sponsored by: Spectralogic
MFC after: 1 month
X-MFC: 238869
