Squashed commit of the following:
net/: Fix some naming inconsistencies, Fix final compilation issies.
net/inet/inet_close(): Now that we have logic to drain the buffered TX data, we can implement a proper lingering close.
net/inet,tcp,udp: Add functions to wait for write buffers to drain.
net/udp: Add support for notification when the UDP write buffer becomes empty.
net/tcp: Add support for notification when the TCP write buffer becomes empty.
sched/wqueue/kwork_notifier.c: Redesign some data structures. struct works_s must appear at the beginning of the notifier entry structure. That is because it contains the work queue indices. This solves a harfault issue.
net/tcp/tcp_netpoll.c: tcp_iob_work() needs to free the allocated argument when it is finished.
net/tcp/tcp_send_buffered.c: Extend psock_tcp_cansend() so that it also requires that at least on IOB is also avaialble.
mm/iob: iob_navail() was returning the number of free IOB chain queue entries, not the number of free IOBs. Completely misnamed.
net/tcp/tcp_netpoll.c: Add logic to receive notifications when IOBs are freed (Needs CONFIG_NET_TCP_WRITE_BUFFERS and CONFIG_IOB_NOTIFIER). At present, does nothing because the logic in in psock_tcp_cansend() does not check for the availability of IOBs. That will change.
Squashed commit of the following:
Fix up some final compile isses.
net/netdev: Convert the network down notification logic to use the new wqueue-based notification factility.
net/udp: Convert the UDP readahead notification logic to use the new wqueue-based notification factility.
net/tcp: Convert the TCP readahead notification logic to use the new wqueue-based notification factility.
mm/iob: Convert the IOB notification logic to use the new wqueue-based notification factility.
sched/wqueue: Signals are not good IPCs to support the target poll functionality for several reasons including the amount of data that can be passed with a signal and in the fact that in protected and kernel modes, user threads executing signal handlers in protected, kernel memory is problematic. Instead, convert the same logic to perform the notifications via function callback on the high priority work queue.
sched/wqueue: Modify high priority work queue to support multiple threads.
sched/wqueue and libs/libc/wqueue: workqueues don't need set global data to zero since .bss is cleared automatically. Removing this unnecessary initialization also avoids the loss the work items queued before initialization.
Squashed commit of the following:
sched: Rename all use of system_t to clock_t.
syscall: Rename all use of system_t to clock_t.
net: Rename all use of system_t to clock_t.
libs: Rename all use of system_t to clock_t.
fs: Rename all use of system_t to clock_t.
drivers: Rename all use of system_t to clock_t.
arch: Rename all use of system_t to clock_t.
include: Remove definition of systime_t; rename all use of system_t to clock_t.
