devices. The implementation allows read and write filters to be
created and piggybacks on the poll() file operation to determine when
a filter should trigger. The piggyback mechanism is simply to check
for the EWOULDBLOCK or EAGAIN return code from read(), write() or
ioctl() system calls and then update the kqueue() polling state bits.
The implementation is similar to the one found in the cuse(3) module.
Refer to sys/fs/cuse/*.[ch] for more details.
MFC after: 1 week
Sponsored by: Mellanox Technologies
printk_ratelimited() in the LinuxKPI.
While at it fix the inclusion guard of printk.h to be similar to the
rest of the LinuxKPI header files.
MFC after: 1 week
Sponsored by: Mellanox Technologies
task structure to avoid deadlock when tearing down the VM object
during a process exit.
Found by: markj @
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Allow "struct linux_file" to be refcounted when its "_file" member
is NULL by using its "f_count" field. The reference counts are
transferred to the file structure when the file descriptor is
installed.
- Add missing vdrop() calls for error cases during open().
- Set the "_file" member of "struct linux_file" during open. This
allows use of refcounting through get_file() and fput() with LinuxKPI
character devices.
MFC after: 1 week
Sponsored by: Mellanox Technologies
kit, CK, in the LinuxKPI.
When threads are pinned to a CPU core or when there is only one CPU,
it can happen that a higher priority thread can call the CK
synchronize function while a lower priority thread holds the read
lock. Because the CK's synchronize is a simple wait loop this can lead
to a deadlock situation. To solve this problem use the recently
introduced CK's wait callback function.
When detecting a CK blocking condition figure out the lowest priority
among the blockers and update the calling thread's priority and
yield. If another CPU core is holding the read lock, pin the thread to
the blocked CPU core and update the priority. The calling threads
priority and CPU bindings are restored before return.
If a thread holding a CK read lock is detected to be sleeping, pause()
will be used instead of yield().
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Move all bitmap related functions from bitops.h to bitmap.h, similar
to what Linux does.
- Apply some minor code cleanup and simplifications to optimize the
generated code when using static inline functions.
- Implement the following list of bitmap functions which are needed by
drm-next and ibcore:
- bitmap_find_next_zero_area_off()
- bitmap_find_next_zero_area()
- bitmap_or()
- bitmap_and()
- bitmap_xor()
- Add missing include directives to the qlnxe driver
(davidcs@ has been notified)
MFC after: 1 week
Sponsored by: Mellanox Technologies
In FreeBSD thread IDs and procedure IDs have distinct number
spaces. When asking for the group leader task ID in the LinuxKPI,
return the procedure ID and let this resolve to the first task in the
procedure having a valid LinuxKPI task structure pointer.
MFC after: 1 week
Sponsored by: Mellanox Technologies
like open, close and fault using the character device pager.
Some notes about the implementation:
1) Linux drivers set the vm_ops and vm_private_data fields during a
mmap() call to indicate that the driver wants to use the LinuxKPI VM
operations. Else these operations are not used.
2) The vm_private_data pointer is associated with a VM area structure
and inserted into an internal LinuxKPI list. If the vm_private_data
pointer already exists, the existing VM area structure is used instead
of the allocated one which gets freed.
3) The LinuxKPI's vm_private_data pointer is used as the callback
handle for the FreeBSD VM object. The VM subsystem in FreeBSD has a
similar list to identify equal handles and will only call the
character device pager's close function once.
4) All LinuxKPI VM operations are serialized through the mmap_sem
sempaphore, which is per procedure, which prevents simultaneous access
to the shared VM area structure when receiving page faults.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
the LinuxKPI for accessing user-space memory in the kernel.
Add functions to hold and wire physical page(s) based on a given range
of user-space virtual addresses.
Add functions to get and put a reference on, wire, hold, mark
accessed, copy and dirty a physical page.
Add new VM related structures and defines as a preparation step for
advancing the memory map capabilities of the LinuxKPI.
Add function to figure out if a virtual address was allocated using
malloc().
Add function to convert a virtual kernel address into its physical
page pointer.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
functions in the LinuxKPI. Add a usage atomic to the task_struct
structure to facilitate refcounting the task structure when returned
from get_pid_task(). The get_task_struct() and put_task_struct()
function is used to manage atomic refcounting. After this change the
task_struct should only be freed through put_task_struct().
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
some associated helper functions in the LinuxKPI. Let the existing
linux_alloc_current() function allocate and initialize the new
structure and let linux_free_current() drop the refcount on the memory
mapping structure. When the mm_struct's refcount reaches zero, the
structure is freed.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
pairwise to support the FreeBSD way of pushing and popping the page
fault flags. Ensure this by requiring every occurrence of pagefault
disable function call to have a corresponding pagefault enable call.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
Support is implemented by mapping Linux's "struct net" into FreeBSD's
"struct vnet". Currently only vnet0 is supported by ibcore.
MFC after: 1 week
Sponsored by: Mellanox Technologies
When locking a mutex and deadlock is detected the first mutex lock
call that sees the deadlock will return -EDEADLK .
MFC after: 1 week
Sponsored by: Mellanox Technologies
Add support for using mutexes during KDB and shutdown. This is also
required for doing mode-switching during panic for drm-next.
Add new mutex functions mutex_init_witness() and mutex_destroy()
allowing LinuxKPI mutexes to be tracked by witness.
Declare mutex_is_locked() and mutex_is_owned() like inline functions
to get cleaner warnings. These functions are used inside WARN_ON()
statements which might look a bit odd if these functions get fully
expanded.
Give mutexes better debug names through the mutex_name() macro when
WITNESS_ALL is defined. The mutex_name() macro can prefix parts of the
filename and line number before the mutex name.
MFC after: 1 week
Sponsored by: Mellanox Technologies
Put large functions into linux_slab.c instead of declaring them static
inline.
Add support for more memory allocation wrappers like kmalloc_array()
and __vmalloc().
Make sure either the M_WAITOK or the M_NOWAIT flag is set and mask
away unused memory allocation flags before calling FreeBSD's malloc()
routine.
Move kmalloc_node() definition to slab.h where it belongs.
Implement support for the SLAB_DESTROY_BY_RCU feature when creating a
kmem_cache which basically means kmem_cache memory is freed using
call_rcu().
MFC after: 1 week
Sponsored by: Mellanox Technologies
LinuxKPI. When the type of the argument is constant the temporary
variable cannot be assigned after the barrier. Instead assign the
temporary variable by initialization.
MFC after: 1 week
Sponsored by: Mellanox Technologies
This change makes the workqueue implementation behave more like in
Linux, both functionality wise and structure wise.
All workqueue code has been moved to linux_work.c
Add an atomic based statemachine to the work_struct to ensure proper
operation. Prior to this change struct_work was directly mapped to a
FreeBSD task. When a taskqueue has multiple threads the same task may
end up being executed on more than one worker thread simultaneously.
This might cause problems with code coming from Linux, which expects
serial behaviour, similar to Linux tasklets.
Move all global workqueue function names into the linux_xxx domain to
avoid symbol name clashes in the future.
Implement a few more workqueue related functions and macros.
Create two multithreaded taskqueues for the LinuxKPI during module
load, one for time-consuming callbacks and one for non-time consuming
callbacks.
MFC after: 1 week
Sponsored by: Mellanox Technologies
WITNESS_ALL is defined. The lock name is based on the filename and
line number where the initialisation happens.
MFC after: 1 week
Sponsored by: Mellanox Technologies
- Optimise the RCU implementation to not allocate and free
ck_epoch_records during runtime. Instead allocate two sets of
ck_epoch_records per CPU for general purpose use. The first set is
only used for reader locks and the second set is only used for
synchronization and barriers and is protected with a regular mutex to
prevent simultaneous issues.
- Move the task structure away from the rcu_head structure and into
the per-CPU structures. This allows the size of the rcu_head structure
to be reduced down to the size of two pointers.
- Fix a bug where the linux_rcu_barrier() function only waited for one
per-CPU epoch record to be completed instead of all.
- Use a critical section or a mutex to protect ck_epoch_begin() and
ck_epoch_end() depending on RCU or SRCU type. All the ck_epoch_xxx()
functions, except ck_epoch_register(), ck_epoch_unregister() and
ck_epoch_recycle() are not re-entrant and needs a critical section or
a mutex to operate in the LinuxKPI, after inspecting the CK
implementation of the above mentioned functions. The simultaneous
issues arise from per-CPU epoch records being shared between multiple
threads depending on the amount of taskswitching and how many threads
are involved with the RCU and SRCU operations.
- Properly free all epoch records by using safe list traversal at
LinuxKPI module unload. It turns out the ck_epoch_recycle() always
have the records on an internal list and use a flag in the epoch
record to track allocated and free entries. This would lead to use
after free during module unload.
- Remove redundant synchronize_rcu() call from the
linux_compat_uninit() function. Let the linux_rcu_runtime_uninit()
function do the final rcu_barrier() instead.
MFC after: 1 week
Sponsored by: Mellanox Technologies
