Problem:
selwakeup required calling pfind which would cause lock order
reversals with the allproc_lock and the per-process filedesc lock.
Solution:
Instead of recording the pid of the select()'ing process into the
selinfo structure, actually record a pointer to the thread. To
avoid dereferencing a bad address all the selinfo structures that
are in use by a thread are kept in a list hung off the thread
(protected by sellock). When a selwakeup occurs the selinfo is
removed from that threads list, it is also removed on the way out
of select or poll where the thread will traverse its list removing
all the selinfos from its own list.
Problem:
Previously the PROC_LOCK was used to provide the mutual exclusion
needed to ensure proper locking, this couldn't work because there
was a single condvar used for select and poll and condvars can
only be used with a single mutex.
Solution:
Introduce a global mutex 'sellock' which is used to provide mutual
exclusion when recording events to wait on as well as performing
notification when an event occurs.
Interesting note:
schedlock is required to manipulate the per-thread TDF_SELECT
flag, however if given its own field it would not need schedlock,
also because TDF_SELECT is only manipulated under sellock one
doesn't actually use schedlock for syncronization, only to protect
against corruption.
Proc locks are no longer used in select/poll.
Portions contributed by: davidc
-#if defined(__FreeBSD__) && __FreeBSD_version__ >= 500023
+#if defined(__FreeBSD__) && __FreeBSD_version >= 500023
is a genuine bug -- __FreeBSD_version__ does not exist.
The other one:
-#if (__FreeBSD__ < 5)
+#if (__FreeBSD_version < 500000)
pops out when you cross-compile the code:
__FreeBSD__ is a compiler predefine,
__FreeBSD_version is defined in <sys/param.h> .
Given that in this case (and all others in sys/dev/usb and sys/i4b)
the goal is to adapt to a different kernel interface, and not to
a compiler feature, I believe the correct form is the second one
(in the best case the two are synonyms so the change does not break
anything anyways).
it worked- but I ran into a case with a 2204 where commands were being lost
right and left. Best be safe.
For target mode, or things called if we call isp_handle_other response- note
that we might have dropped locks by changing the output pointer so we bail
from the loop. It's the responsibility of the entity dropping the lock to
make sure that we let the f/w know we've read thus far into the response
queue (else we begin processing the same entries again- blech!).
MFC after: 1 day
the upcoming 7.4 family (7xxx controllers).
- improved error reporting and handling
- more diagnostic output
- add extra command packet definitions
- merge sources again with -stable
by removing parentheses. The main bug is in gcc: on machines with
64-bit longs and 64-bit long longs,
(unsigned long long)rdp->total_sectors / ((1024L * 1024L) / DEV_BSIZE))
has type plain unsigned long instead of the correctly promoted type
unsigned long long, so it can not be printfed using %llu format. Even
1ULL / 1L is mispromoted. Anyway, casting the correct operand
automatically avoids the problem. We do not want to to pessimize the
division; we just want to convert to a common maximal type for printing.
Some buggy firmware workarounds. Fix some endian bugs.
These reduce the diffs from NetBSD, but NetBSD does have more changes since
my last manual merge.
Link if only ATAPI device in kernel config
Remove unused #includes
Rearrange a bit in ata-raid to make diff against -stable smaller
Enable wc as default again, dunne how this happend...
This makes other power-management system (APM for now) to be able to
generate power profile change events (ie. AC-line status changes), and
other kernel components, not only the ACPI components, can be notified
the events.
- move subroutines in acpi_powerprofile.c (removed) to kern/subr_power.c
- call power_profile_set_state() also from APM driver when AC-line
status changes
- add call-back function for Crusoe LongRun controlling on power
profile changes for a example
