kernel/fifo: just send a disconnect for readers without writers.

just send an error for writers without readers

Change-Id: I4808e5dec29c840b72423a1bb10cb8f0ebc23bb5
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6419
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

kernel/fifo: fix commands like "tail -f file | grep"

'tail' selects read events on its write-only file descriptors,
so let's use B_SELECT_READ only for read-write file descriptors.

Change-Id: I5bb3837f82a7b06ec367fe871c15d67beb2d412c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6417
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

kernel/fifo: Add missing check for B_SELECT_READ in Deselect().

This should have been part of 27fda3e46f1422503a08a3d34e4618778b2dc146.
Fixes #17826.

kernel/fifo: Properly support opening FIFOs in O_RDWR mode.

While pipe() only supports a read end and a write end, named FIFOs
are supposed to allow opening in read/write mode (which, indeed,
is something the Fish shell seems to require.)

The code that checks open_mode in the read/write routines was introduced
all the way back in 2003 (2469f26dfc618dac7853c0de146df7872e60623f).
At that time, the VFS did not do open_mode checks on FDs in the
I/O syscalls, so these doubled as permissions checks. Now, however,
the VFS does check that in common_user_io, so we can remove these
entirely and let things behave as they should.

Additionally, there is now also no reason to prevent select()ing
on both events for the same FD independent of open_mode, so
allow that too.

Change-Id: Ib3cba76d18e91b7c00d1695e8d29dd47cae06b79
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5427
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

kernel: fix trace build for fd.cpp and fifo.cpp

Change-Id: I12b2e85926ae63eaba5c077343cdaa2362cf8af1
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5391
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

fifo: fsync() returns EINVAL

fix #15288

Change-Id: Ic86bcec662c81cb04b743ec077cc8a2f3941f96e
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3379
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

fifo: revert broken fix

fifo: wakeup readers not checking POLLHUP/B_SELECT_DISCONNECTED
For readers waiting in select() or simply in read(),
B_SELECT_DISCONNECTED notification didn't wake them anymore.
Now, cascade notifications to be sure to wake them, either
on POLLHUP, POOLERR/B_SELECT_ERROR or, at worst, from read().

See #7859 for details.

fifo: fix #7859

More useless inclusions of khash.h

FIFO: Handle user reads/writes more correctly

* Determine whether called from userland or kernel.
* Check the buffer address via IS_USER_ADDRESS(), if from userland.
* Simplify things by merging UserRead() with Read() and
UserWrite() with Write().

FIFO: Implement FION{BIO,READ}, B_SET_[NON]BLOCKING_IO ioctls

FIFO: More correct locking when accessing file_cookie::open_mode

VFS FIFO: Add "fifo" KDL command

Prints information about a FIFO node and, optionally, its data buffer
content.

VFS FIFO: Enlarge FIFO buffer sizes

* Increase FIFO buffer capacity from 32 to 64 KiB and the FIFO atomic
write size ({BUF_SIZE}) from 512 bytes to 4 KiB (both like Linux).
* Fix *pathconf(..., _PC_PIPE_BUF). It was returning 4 KiB although the
implemented atomic write size was 512 bytes only. Now both *pathconf()
and the FIFO implementation refer to the same constant.

VFS FIFO: Fix RingBuffer::Read()/Write() return types

size_t -> ssize_t, since they may actually return an error code.

kernel: Add thread_unblock() and use it where possible

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96

Merged the signals branch into trunk, with these changes:
* The team and thread kernel structures have been renamed to Team and Thread
respectively and moved into the new BKernel namespace.
* Several (kernel add-on) sources have been converted from C to C++ since
private kernel headers are included that are no longer C compatible.

Changes after merging:
* Fixed gcc 2 build (warnings mainly in the scary firewire bus manager).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40196 a95241bf-73f2-0310-859d-f6bbb57e9c96

More fixes.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39009 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Made sure that at least the common case with a single writer exits write()
once the file descriptor is closed.
* Reinstantiated the FIFO functionality as long there are no writers yet as
explained by Ingo.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37883 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Cleanup, no functional change.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37861 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Implemented a different way to notify waiting read()s when a file descriptor
is closed; their ReadRequest will now be notified with B_FILE_ERROR.
* This is a better fix for #5947, though note that I left the changes in
Inode::ReadDataFromBuffer() in place, as I think this is what POSIX requires.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37860 a95241bf-73f2-0310-859d-f6bbb57e9c96

* I see no reason for the fActive check here. Until Ingo enlightens me, this
fixes bug #5947, IOW BePDF should now close fine again :-)


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37836 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Improved debug output.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37835 a95241bf-73f2-0310-859d-f6bbb57e9c96

Changed the type of the "op" parameter of the fs_vnode_ops::ioctl() hook and
the _kern_ioctl() syscall from ulong to uint32.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36927 a95241bf-73f2-0310-859d-f6bbb57e9c96

* All scheduler implementations:
- enqueue_in_run_queue() no longer returns whether rescheduling is supposed
to happen. Instead is sets cpu_ent::invoke_scheduler on the current CPU.
- reschedule() does now handle cpu_ent::invoke_scheduler_if_idle(). No need
to let all callers do that.
* thread_unblock[_locked]() no longer return whether rescheduling is supposed
to happen.
* Got rid of the B_INVOKE_SCHEDULER handling. The interrupt hooks really
can't know, when it makes sense to reschedule or not.
* Introduced scheduler_reschedule_if_necessary[_locked]() functions for
checking+invoking the scheduler.
* Some semaphore functions (e.g. delete_sem()) invoke the scheduler now, if
they wake up anything with greater priority.
I've also tried to add scheduler invocations in the condition variable and
mutex/rw_lock code, but that actually has a negative impact on performance,
probably because it causes too much ping-ponging between threads when
multiple locking primitives are involved.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34657 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Moved the VM headers into subdirectory vm/.
* Renamed vm_cache.h/vm_address_space.h to VMCache.h/VMAddressSpace.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34449 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Made the internal file systems correctly handle the timespec struct stat
times.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31059 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixing warnings under GCC4 in preparation to enable -Werror there as well:
* Replaced the use of offsetof() for structs that aren't PODs. Add a
offset_of_member() macro to util/khash.h because that's what it's used for
in our cases.
* Change the signature of add_debugger_command()/remove_debugger_command() on
GCC > 2 to avoid the depricated conversion from string constants to char *.
* Adding some "suggested" parenthesis. I know that not everyone likes that, but
it pointed out at least one bug that is fixed here as well.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29113 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixed serious race condition: If the thread waiting for a request was
interrupted, another thread closing the other end of the pipe could
invoke thread_unblock() while the first thread already entered
mutex_lock(). This would make the first thread think it successfully
locked the mutex, without removing its (on-stack) wait entry from the
mutex queue, thus leading to crashes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28195 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Added FS interface hooks io() and cancel_io(). The former is supposed
to provide asynchrounous (or only synchronous, if asynchronous is not
supported) I/O request support. It will eventually replace
{read,write}_pages(). None of the FS implementations implement them
yet.
* Implemented some support functions for request-based I/O. File system
implementations can use do_fd_io() which passes an I/O request to the
layer responsible for a given FD, and do_iterative_fd_io(), which
translates a request for a file to subrequests for the underlying
device and passes them on. Both fall back to synchrounous processing
when the io() hook is not supported.
Furthermore added vfs_synchronous_io() which should be handy for the
devfs to perform io_requests synchronously for devices that don't
support the io() hook.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26655 a95241bf-73f2-0310-859d-f6bbb57e9c96

* bfs_fsync() was the only place which could cause the
fs_vnode_ops::write_pages() to be called with fsReenter = true. Since
this is no longer the case, the argument has become superfluous. For
read_pages() it always was. Removed the argument from the functions
and all functions that propagated it.
* Some whitespace at the end of lines was removed.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26579 a95241bf-73f2-0310-859d-f6bbb57e9c96

axeld + bonefish:
Changed condition variables so that it is allowed to block (e.g. lock
mutexes etc.) between Add() and Wait(). This fixes #2059, since the
block writer used them this way and could thusly fail to wait for a
condition variable, causing a temporary stack object to be used past its
lifetime.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25525 a95241bf-73f2-0310-859d-f6bbb57e9c96

Replaced benaphores with mutexes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25378 a95241bf-73f2-0310-859d-f6bbb57e9c96

Removed superfluous uint32 ref parameter from select() FS hook.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25268 a95241bf-73f2-0310-859d-f6bbb57e9c96

Use the thread blocking functions instead of a condition variable for
read request. Can probably be done for writers as well.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25111 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Detemplatized ConditionVariable{Entry}. Merged them with their
respective Private* base class.
* Changed sigwait() and sigsuspend() to use thread_block() instead of a
condition variable.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25100 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Introduced a set of functions (thread_prepare_to_block(),
thread_block(), thread_unblock(),...) that allow a thread to wait for
something without needing a semaphore or condition variable. It can
simply block and another thread can unblock it. Supports timeouts and
interrupting. Both semaphores and condition variables use this
common mechanism, now.
* Semaphores:
- Some simplifications due to the thread blocking mechanism.
- Changed locking order to sem -> thread. It was the other way around
before and when introducing the wait_for_objects() support I had
also introduced a situation where the locking was reverse, which
could potentially cause a dead lock on SMP systems.
- Instead of queueing thread structures, a semaphore queues
queued_thread entries now, which are created on the stack. The
thread::sem structure could thus be removed.
- Added sem_entry::net_count, which is sem_entry::count plus the
acquisition count of all waiting threads. This number is needed in
remove_thread_from_sem() and instead of computing it there we
maintain it.
- Fixed remove_thread_from_sem(). It would not unblock threads, if
the sem count was <= 0.
- Made sem::last_acquirer unconditional. It is actually needed for
sem_info::latest_holder. Fixed fill_sem_info() accordingly.
- Added some optional tracing output, though only via ktrace_printf().
* Condition variables:
- Could be simplified significantly through the use of the thread
blocking mechanism. Removed a good deal of unnecessary code.
- Moved the ConditionVariableEntry "flags" parameter from Wait() to
Add(), and adjusted all places where condition variables are used
accordingly.
* snooze() uses thread_block_with_timeout() instead of a semaphore.
* Simplified thread interrupting in the signal and user debugger code.
Instead of separate functions for threads waiting on a semaphore or
condititon variable, we only have a single thread_interrupt(), now.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25099 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Renamed pipefs.cpp to fifo.cpp.
* Removed the pipefs functionality. We only need to support FIFO nodes.
* Renamed the remaining pipefs_*() functions to fifo_*().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24834 a95241bf-73f2-0310-859d-f6bbb57e9c96

More useless inclusions of khash.h

FIFO: Handle user reads/writes more correctly

* Determine whether called from userland or kernel.
* Check the buffer address via IS_USER_ADDRESS(), if from userland.
* Simplify things by merging UserRead() with Read() and
UserWrite() with Write().

FIFO: Implement FION{BIO,READ}, B_SET_[NON]BLOCKING_IO ioctls

FIFO: More correct locking when accessing file_cookie::open_mode

VFS FIFO: Add "fifo" KDL command

Prints information about a FIFO node and, optionally, its data buffer
content.

VFS FIFO: Enlarge FIFO buffer sizes

* Increase FIFO buffer capacity from 32 to 64 KiB and the FIFO atomic
write size ({BUF_SIZE}) from 512 bytes to 4 KiB (both like Linux).
* Fix *pathconf(..., _PC_PIPE_BUF). It was returning 4 KiB although the
implemented atomic write size was 512 bytes only. Now both *pathconf()
and the FIFO implementation refer to the same constant.

VFS FIFO: Fix RingBuffer::Read()/Write() return types

size_t -> ssize_t, since they may actually return an error code.

kernel: Add thread_unblock() and use it where possible

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96

Merged the signals branch into trunk, with these changes:
* The team and thread kernel structures have been renamed to Team and Thread
respectively and moved into the new BKernel namespace.
* Several (kernel add-on) sources have been converted from C to C++ since
private kernel headers are included that are no longer C compatible.

Changes after merging:
* Fixed gcc 2 build (warnings mainly in the scary firewire bus manager).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40196 a95241bf-73f2-0310-859d-f6bbb57e9c96

More fixes.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39009 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Made sure that at least the common case with a single writer exits write()
once the file descriptor is closed.
* Reinstantiated the FIFO functionality as long there are no writers yet as
explained by Ingo.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37883 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Cleanup, no functional change.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37861 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Implemented a different way to notify waiting read()s when a file descriptor
is closed; their ReadRequest will now be notified with B_FILE_ERROR.
* This is a better fix for #5947, though note that I left the changes in
Inode::ReadDataFromBuffer() in place, as I think this is what POSIX requires.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37860 a95241bf-73f2-0310-859d-f6bbb57e9c96

* I see no reason for the fActive check here. Until Ingo enlightens me, this
fixes bug #5947, IOW BePDF should now close fine again :-)


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37836 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Improved debug output.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37835 a95241bf-73f2-0310-859d-f6bbb57e9c96

Changed the type of the "op" parameter of the fs_vnode_ops::ioctl() hook and
the _kern_ioctl() syscall from ulong to uint32.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36927 a95241bf-73f2-0310-859d-f6bbb57e9c96

* All scheduler implementations:
- enqueue_in_run_queue() no longer returns whether rescheduling is supposed
to happen. Instead is sets cpu_ent::invoke_scheduler on the current CPU.
- reschedule() does now handle cpu_ent::invoke_scheduler_if_idle(). No need
to let all callers do that.
* thread_unblock[_locked]() no longer return whether rescheduling is supposed
to happen.
* Got rid of the B_INVOKE_SCHEDULER handling. The interrupt hooks really
can't know, when it makes sense to reschedule or not.
* Introduced scheduler_reschedule_if_necessary[_locked]() functions for
checking+invoking the scheduler.
* Some semaphore functions (e.g. delete_sem()) invoke the scheduler now, if
they wake up anything with greater priority.
I've also tried to add scheduler invocations in the condition variable and
mutex/rw_lock code, but that actually has a negative impact on performance,
probably because it causes too much ping-ponging between threads when
multiple locking primitives are involved.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34657 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Moved the VM headers into subdirectory vm/.
* Renamed vm_cache.h/vm_address_space.h to VMCache.h/VMAddressSpace.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34449 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Made the internal file systems correctly handle the timespec struct stat
times.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31059 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixing warnings under GCC4 in preparation to enable -Werror there as well:
* Replaced the use of offsetof() for structs that aren't PODs. Add a
offset_of_member() macro to util/khash.h because that's what it's used for
in our cases.
* Change the signature of add_debugger_command()/remove_debugger_command() on
GCC > 2 to avoid the depricated conversion from string constants to char *.
* Adding some "suggested" parenthesis. I know that not everyone likes that, but
it pointed out at least one bug that is fixed here as well.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29113 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixed serious race condition: If the thread waiting for a request was
interrupted, another thread closing the other end of the pipe could
invoke thread_unblock() while the first thread already entered
mutex_lock(). This would make the first thread think it successfully
locked the mutex, without removing its (on-stack) wait entry from the
mutex queue, thus leading to crashes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28195 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Added FS interface hooks io() and cancel_io(). The former is supposed
to provide asynchrounous (or only synchronous, if asynchronous is not
supported) I/O request support. It will eventually replace
{read,write}_pages(). None of the FS implementations implement them
yet.
* Implemented some support functions for request-based I/O. File system
implementations can use do_fd_io() which passes an I/O request to the
layer responsible for a given FD, and do_iterative_fd_io(), which
translates a request for a file to subrequests for the underlying
device and passes them on. Both fall back to synchrounous processing
when the io() hook is not supported.
Furthermore added vfs_synchronous_io() which should be handy for the
devfs to perform io_requests synchronously for devices that don't
support the io() hook.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26655 a95241bf-73f2-0310-859d-f6bbb57e9c96

* bfs_fsync() was the only place which could cause the
fs_vnode_ops::write_pages() to be called with fsReenter = true. Since
this is no longer the case, the argument has become superfluous. For
read_pages() it always was. Removed the argument from the functions
and all functions that propagated it.
* Some whitespace at the end of lines was removed.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26579 a95241bf-73f2-0310-859d-f6bbb57e9c96

axeld + bonefish:
Changed condition variables so that it is allowed to block (e.g. lock
mutexes etc.) between Add() and Wait(). This fixes #2059, since the
block writer used them this way and could thusly fail to wait for a
condition variable, causing a temporary stack object to be used past its
lifetime.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25525 a95241bf-73f2-0310-859d-f6bbb57e9c96

Replaced benaphores with mutexes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25378 a95241bf-73f2-0310-859d-f6bbb57e9c96

Removed superfluous uint32 ref parameter from select() FS hook.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25268 a95241bf-73f2-0310-859d-f6bbb57e9c96

Use the thread blocking functions instead of a condition variable for
read request. Can probably be done for writers as well.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25111 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Detemplatized ConditionVariable{Entry}. Merged them with their
respective Private* base class.
* Changed sigwait() and sigsuspend() to use thread_block() instead of a
condition variable.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25100 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Introduced a set of functions (thread_prepare_to_block(),
thread_block(), thread_unblock(),...) that allow a thread to wait for
something without needing a semaphore or condition variable. It can
simply block and another thread can unblock it. Supports timeouts and
interrupting. Both semaphores and condition variables use this
common mechanism, now.
* Semaphores:
- Some simplifications due to the thread blocking mechanism.
- Changed locking order to sem -> thread. It was the other way around
before and when introducing the wait_for_objects() support I had
also introduced a situation where the locking was reverse, which
could potentially cause a dead lock on SMP systems.
- Instead of queueing thread structures, a semaphore queues
queued_thread entries now, which are created on the stack. The
thread::sem structure could thus be removed.
- Added sem_entry::net_count, which is sem_entry::count plus the
acquisition count of all waiting threads. This number is needed in
remove_thread_from_sem() and instead of computing it there we
maintain it.
- Fixed remove_thread_from_sem(). It would not unblock threads, if
the sem count was <= 0.
- Made sem::last_acquirer unconditional. It is actually needed for
sem_info::latest_holder. Fixed fill_sem_info() accordingly.
- Added some optional tracing output, though only via ktrace_printf().
* Condition variables:
- Could be simplified significantly through the use of the thread
blocking mechanism. Removed a good deal of unnecessary code.
- Moved the ConditionVariableEntry "flags" parameter from Wait() to
Add(), and adjusted all places where condition variables are used
accordingly.
* snooze() uses thread_block_with_timeout() instead of a semaphore.
* Simplified thread interrupting in the signal and user debugger code.
Instead of separate functions for threads waiting on a semaphore or
condititon variable, we only have a single thread_interrupt(), now.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25099 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Renamed pipefs.cpp to fifo.cpp.
* Removed the pipefs functionality. We only need to support FIFO nodes.
* Renamed the remaining pipefs_*() functions to fifo_*().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24834 a95241bf-73f2-0310-859d-f6bbb57e9c96