- Cleanup of unused macros for VFS - FS protocols
- Update servers/vfs/README to reflect the new requests names.
- Alphabetically re-order the message union, as well as minor
formatting, for readability.
Change-Id: Ief7c38489e93bcf5f795dccbf3a8e10b44b95af4
- introduce new call numbers, names, and field aliases;
- initialize request messages to zero for all ABI calls;
- format callnr.h in the same way as com.h;
- redo call tables in both servers;
- remove param.h namespace pollution in the servers;
- make brk(2) go to VM directly, rather than through PM;
- remove obsolete BRK, UTIME, and WAIT calls;
- clean up path copying routine in VFS;
- move remaining system calls from libminlib to libc;
- correct some errno-related mistakes in libc routines.
Change-Id: I2d8ec5d061cd7e0b30c51ffd77aa72ebf84e2565
Previously, VFS would reopen a character device after a driver crash
if the associated file descriptor was opened with the O_REOPEN flag.
This patch removes support for this feature. The code was complex,
full of uncovered corner cases, and hard to test. Moreover, it did not
actually hide the crash from user applications: they would get an
error code to indicate that something went wrong, and have to decide
based on the nature of the underlying device how to continue.
- remove support for O_REOPEN, and make playwave(1) reopen its device;
- remove support for the DEV_REOPEN protocol message;
- remove all code in VFS related to reopening character devices;
- no longer change VFS filp reference count and FD bitmap upon filp
invalidation; instead, make get_filp* fail all calls on invalidated
FDs except when obtained with the locktype VNODE_OPCL which is used
by close_fd only;
- remove the VFS fproc file descriptor bitmap entirely, returning to
the situation that a FD is in use if its slot points to a filp; use
FILP_CLOSED as single means of marking a filp as invalidated.
Change-Id: I34f6bc69a036b3a8fc667c1f80435ff3af56558f
The main purpose of this patch is to fix handling of unpause calls
from PM while another call is ongoing. The solution to this problem
sparked a full revision of the threading model, consisting of a large
number of related changes:
- all active worker threads are now always associated with a process,
and every process has at most one active thread working for it;
- the process lock is always held by a process's worker thread;
- a process can now have both normal work and postponed PM work
associated to it;
- timer expiry and non-postponed PM work is done from the main thread;
- filp garbage collection is done from a thread associated with VFS;
- reboot calls from PM are now done from a thread associated with PM;
- the DS events handler is protected from starting multiple threads;
- support for a system worker thread has been removed;
- the deadlock recovery thread has been replaced by a parameter to the
worker_start() function; the number of worker threads has
consequently been increased by one;
- saving and restoring of global but per-thread variables is now
centralized in worker_suspend() and worker_resume(); err_code is now
saved and restored in all cases;
- the concept of jobs has been removed, and job_m_in now points to a
message stored in the worker thread structure instead;
- the PM lock has been removed;
- the separate exec lock has been replaced by a lock on the VM
process, which was already being locked for exec calls anyway;
- PM_UNPAUSE is now processed as a postponed PM request, from a thread
associated with the target process;
- the FP_DROP_WORK flag has been removed, since it is no longer more
than just an optimization and only applied to processes operating on
a pipe when getting killed;
- assignment to "fp" now takes place only when obtaining new work in
the main thread or a worker thread, when resuming execution of a
thread, and in the special case of exiting processes during reboot;
- there are no longer special cases where the yield() call is used to
force a thread to run.
Change-Id: I7a97b9b95c2450454a9b5318dfa0e6150d4e6858
Previously, processing of some replies coming from character drivers
could block on locks, and therefore, such processing was done from
threads that were associated to the character driver process. The
hidden consequence of this was that if all threads were in use, VFS
could drop replies coming from the driver. This patch returns VFS to
a situation where the replies from character drivers are processed
instantly from the main thread, by removing the situations that may
cause VFS to block while handling those replies.
- change the locking model for select, so that it will never block
on any processing that happens after the select call has been set
up, in particular processing of character driver select replies;
- clearly mark all select routines that may never block;
- protect against race conditions in do_select as result of the
locking that still does happen there (as is required for pipes);
- also handle select timers from the main thread;
- move processing of character driver replies into device.c.
Change-Id: I4dc8e69f265cbd178de0fbf321d35f58f067cc57
