Commit graph

81213 commits

Author SHA1 Message Date
Amey Narkhede
56f107d781 PCI: Add pcie_reset_flr() with 'probe' argument
Most reset methods are of the form "pci_*_reset(dev, probe)".  pcie_flr()
was an exception because it relied on a separate pcie_has_flr() function
instead of taking a "probe" argument.

Add "pcie_reset_flr(dev, probe)" to follow the convention.  Remove
pcie_has_flr().

Some pcie_flr() callers that did not use pcie_has_flr() remain.

[bhelgaas: commit log, rework pcie_reset_flr() to use dev->devcap directly]
Link: https://lore.kernel.org/r/20210817180500.1253-3-ameynarkhede03@gmail.com
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
2021-08-17 15:23:13 -05:00
Amey Narkhede
6913924480 PCI: Cache PCIe Device Capabilities register
Add a new member called devcap in struct pci_dev for caching the PCIe
Device Capabilities register to avoid reading PCI_EXP_DEVCAP multiple
times.

Refactor pcie_has_flr() to use cached device capabilities.

Link: https://lore.kernel.org/r/20210817180500.1253-2-ameynarkhede03@gmail.com
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
2021-08-17 15:21:35 -05:00
Lai Jiangshan
bdb0a6548d workqueue: Remove unused WORK_NO_COLOR
WORK_NO_COLOR has no user now, just remove it.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-17 07:49:10 -10:00
Lai Jiangshan
f97a4a1a3f workqueue: Rename "delayed" (delayed by active management) to "inactive"
There are two kinds of "delayed" work items in workqueue subsystem.

One is for timer-delayed work items which are visible to workqueue users.
The other kind is for work items delayed by active management which can
not be directly visible to workqueue users.  We mixed the word "delayed"
for both kinds and caused somewhat ambiguity.

This patch renames the later one (delayed by active management) to
"inactive", because it is used for workqueue active management and
most of its related symbols are named with "active" or "activate".

All "delayed" and "DELAYED" are carefully checked and renamed one by
one to avoid accidentally changing the name of the other kind for
timer-delayed.

No functional change intended.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-17 07:49:09 -10:00
Peter Zijlstra
9ae6ab27f4 static_call: Update API documentation
Update the comment with the new features.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/YQwIorQBHEq+s73b@hirez.programming.kicks-ass.net
2021-08-17 19:09:27 +02:00
Thomas Gleixner
026659b977 locking/local_lock: Add PREEMPT_RT support
On PREEMPT_RT enabled kernels local_lock maps to a per CPU 'sleeping'
spinlock which protects the critical section while staying preemptible. CPU
locality is established by disabling migration.

Provide the necessary types and macros to substitute the non-RT variant.

Co-developed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211306.023630962@linutronix.de
2021-08-17 19:08:49 +02:00
Thomas Gleixner
31552385f8 locking/spinlock/rt: Prepare for RT local_lock
Add the static and runtime initializer mechanics to support the RT variant
of local_lock, which requires the lock type in the lockdep map to be set
to LD_LOCK_PERCPU.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.967526724@linutronix.de
2021-08-17 19:06:13 +02:00
Thomas Gleixner
015680aa4c preempt: Adjust PREEMPT_LOCK_OFFSET for RT
On PREEMPT_RT regular spinlocks and rwlocks are substituted with rtmutex
based constructs. spin/rwlock held regions are preemptible on PREEMPT_RT,
so PREEMPT_LOCK_OFFSET has to be 0 to make the various cond_resched_*lock()
functions work correctly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.804246275@linutronix.de
2021-08-17 19:06:04 +02:00
Thomas Gleixner
bb630f9f7a locking/rtmutex: Add mutex variant for RT
Add the necessary defines, helpers and API functions for replacing struct mutex on
a PREEMPT_RT enabled kernel with an rtmutex based variant.

No functional change when CONFIG_PREEMPT_RT=n

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.081517417@linutronix.de
2021-08-17 19:05:29 +02:00
Peter Zijlstra
2408f7a378 locking/ww_mutex: Add rt_mutex based lock type and accessors
Provide the defines for RT mutex based ww_mutexes and fix up the debug logic
so it's either enabled by DEBUG_MUTEXES or DEBUG_RT_MUTEXES on RT kernels.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.908012566@linutronix.de
2021-08-17 19:05:11 +02:00
Thomas Gleixner
653a5b0bd9 locking/ww_mutex: Abstract out internal lock accesses
Accessing the internal wait_lock of mutex and rtmutex is slightly
different. Provide helper functions for that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.734635961@linutronix.de
2021-08-17 19:05:03 +02:00
Thomas Gleixner
ebf4c55c1d locking/mutex: Make mutex::wait_lock raw
The wait_lock of mutex is really a low level lock. Convert it to a
raw_spinlock like the wait_lock of rtmutex.

[ mingo: backmerged the test_lockup.c build fix by bigeasy. ]

Co-developed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.166863404@linutronix.de
2021-08-17 19:03:33 +02:00
Thomas Gleixner
4f1893ec8c locking/ww_mutex: Move the ww_mutex definitions from <linux/mutex.h> into <linux/ww_mutex.h>
Move the ww_mutex definitions into the ww_mutex specific header where they
belong.

Preparatory change to allow compiling ww_mutexes standalone.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.110216293@linutronix.de
2021-08-17 18:24:31 +02:00
Thomas Gleixner
43d2d52d70 locking/mutex: Move the 'struct mutex_waiter' definition from <linux/mutex.h> to the internal header
Move the mutex waiter declaration from the public <linux/mutex.h> header
to the internal kernel/locking/mutex.h header.

There is no reason to expose it outside of the core code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.054325923@linutronix.de
2021-08-17 18:24:31 +02:00
Thomas Gleixner
8282947f67 locking/rwlock: Provide RT variant
Similar to rw_semaphores, on RT the rwlock substitution is not writer fair,
because it's not feasible to have a writer inherit its priority to
multiple readers. Readers blocked on a writer follow the normal rules of
priority inheritance. Like RT spinlocks, RT rwlocks are state preserving
across the slow lock operations (contended case).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.882793524@linutronix.de
2021-08-17 17:50:51 +02:00
Chuck Lever
b4ab2fea7c SUNRPC: Add RPC_AUTH_TLS protocol numbers
Shared by client and server. See:

https://www.iana.org/assignments/rpc-authentication-numbers/rpc-authentication-numbers.xhtml

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-17 11:47:53 -04:00
Jia He
a2071573d6 sysctl: introduce new proc handler proc_dobool
This is to let bool variable could be correctly displayed in
big/little endian sysctl procfs. sizeof(bool) is arch dependent,
proc_dobool should work in all arches.

Suggested-by: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Signed-off-by: Jia He <hejianet@gmail.com>
[thuth: rebased the patch to the current kernel version]
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-17 11:47:53 -04:00
Chuck Lever
5c11720767 SUNRPC: Fix a NULL pointer deref in trace_svc_stats_latency()
Some paths through svc_process() leave rqst->rq_procinfo set to
NULL, which triggers a crash if tracing happens to be enabled.

Fixes: 89ff87494c ("SUNRPC: Display RPC procedure names instead of proc numbers")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-17 11:47:53 -04:00
Chuck Lever
07a92d009f svcrdma: Convert rdma->sc_rw_ctxts to llist
Relieve contention on sc_rw_ctxt_lock by converting rdma->sc_rw_ctxts
to an llist.

The goal is to reduce the average overhead of Send completions,
because a transport's completion handlers are single-threaded on
one CPU core. This change reduces CPU utilization of each Send
completion by 2-3% on my server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
2021-08-17 11:47:53 -04:00
Chuck Lever
b6c2bfea09 svcrdma: Relieve contention on sc_send_lock.
/proc/lock_stat indicates the the sc_send_lock is heavily
contended when the server is under load from a single client.

To address this, convert the send_ctxt free list to an llist.
Returning an item to the send_ctxt cache is now waitless, which
reduces the instruction path length in the single-threaded Send
handler (svc_rdma_wc_send).

The goal is to enable the ib_comp_wq worker to handle a higher
RPC/RDMA Send completion rate given the same CPU resources. This
change reduces CPU utilization of Send completion by 2-3% on my
server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
2021-08-17 11:47:53 -04:00
Chuck Lever
6c8c84f525 svcrdma: Fewer calls to wake_up() in Send completion handler
Because wake_up() takes an IRQ-safe lock, it can be expensive,
especially to call inside of a single-threaded completion handler.
What's more, the Send wait queue almost never has waiters, so
most of the time, this is an expensive no-op.

As always, the goal is to reduce the average overhead of each
completion, because a transport's completion handlers are single-
threaded on one CPU core. This change reduces CPU utilization of
the Send completion thread by 2-3% on my server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
2021-08-17 11:47:53 -04:00
Chuck Lever
2f0f88f42f SUNRPC: Add svc_rqst_replace_page() API
Replacing a page in rq_pages[] requires a get_page(), which is a
bus-locked operation, and a put_page(), which can be even more
costly.

To reduce the cost of replacing a page in rq_pages[], batch the
put_page() operations by collecting "freed" pages in a pagevec,
and then release those pages when the pagevec is full. This
pagevec is also emptied when each RPC completes.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-08-17 11:47:52 -04:00
Thomas Gleixner
342a93247e locking/spinlock: Provide RT variant header: <linux/spinlock_rt.h>
Provide the necessary wrappers around the actual rtmutex based spinlock
implementation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.712897671@linutronix.de
2021-08-17 17:43:24 +02:00
Thomas Gleixner
051790eecc locking/spinlock: Provide RT specific spinlock_t
RT replaces spinlocks with a simple wrapper around an rtmutex, which turns
spinlocks on RT into 'sleeping' spinlocks. The actual implementation of the
spinlock API differs from a regular rtmutex, as it does neither handle
timeouts nor signals and it is state preserving across the lock operation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.654230709@linutronix.de
2021-08-17 17:41:24 +02:00
Sebastian Andrzej Siewior
e4e17af3b7 locking/rtmutex: Reduce <linux/rtmutex.h> header dependencies, only include <linux/rbtree_types.h>
We have the following header dependency problem on RT:

 - <linux/rtmutex.h> needs the definition of 'struct rb_root_cached'.
 - <linux/rbtree.h> includes <linux/kernel.h>, which includes <linux/spinlock.h>

That works nicely for non-RT enabled kernels, but on RT enabled kernels
spinlocks are based on rtmutexes, which creates another circular header
dependency as <linux/spinlocks.h> will require <linux/rtmutex.h>.

Include <linux/rbtree_types.h> instead.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.598003167@linutronix.de
2021-08-17 17:37:26 +02:00
Sebastian Andrzej Siewior
089050cafa rbtree: Split out the rbtree type definitions into <linux/rbtree_types.h>
So we have this header dependency problem on RT:

 - <linux/rtmutex.h> needs the definition of 'struct rb_root_cached'.
 - <linux/rbtree.h> includes <linux/kernel.h>, which includes <linux/spinlock.h>.

That works nicely for non-RT enabled kernels, but on RT enabled kernels
spinlocks are based on rtmutexes, which creates another circular header
dependency, as <linux/spinlocks.h> will require <linux/rtmutex.h>.

Split out the type definitions and move them into their own header file so
the rtmutex header can include just those.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.542123501@linutronix.de
2021-08-17 17:36:48 +02:00
Sebastian Andrzej Siewior
cbcebf5bd3 locking/lockdep: Reduce header dependencies in <linux/debug_locks.h>
The inclusion of printk.h leads to a circular dependency if spinlock_t is
based on rtmutexes on RT enabled kernels.

Include only atomic.h (xchg()) and cache.h (__read_mostly) which is all
what debug_locks.h requires.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.484161136@linutronix.de
2021-08-17 17:29:10 +02:00
Sebastian Andrzej Siewior
a403abbdc7 locking/rtmutex: Prevent future include recursion hell
rtmutex only needs raw_spinlock_t, but it includes spinlock_types.h, which
is not a problem on an non RT enabled kernel.

RT kernels substitute regular spinlocks with 'sleeping' spinlocks, which
are based on rtmutexes, and therefore must be able to include rtmutex.h.

Include <linux/spinlock_types_raw.h> instead.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.428224188@linutronix.de
2021-08-17 17:27:28 +02:00
Thomas Gleixner
4f084ca74c locking/spinlock: Split the lock types header, and move the raw types into <linux/spinlock_types_raw.h>
Move raw_spinlock into its own file. Prepare for RT 'sleeping spinlocks', to
avoid header recursion, as RT locks require rtmutex.h, which in turn requires
the raw spinlock types.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.371269088@linutronix.de
2021-08-17 17:26:27 +02:00
Thomas Gleixner
42254105df locking/rwsem: Add rtmutex based R/W semaphore implementation
The RT specific R/W semaphore implementation used to restrict the number of
readers to one, because a writer cannot block on multiple readers and
inherit its priority or budget.

The single reader restricting was painful in various ways:

 - Performance bottleneck for multi-threaded applications in the page fault
   path (mmap sem)

 - Progress blocker for drivers which are carefully crafted to avoid the
   potential reader/writer deadlock in mainline.

The analysis of the writer code paths shows that properly written RT tasks
should not take them. Syscalls like mmap(), file access which take mmap sem
write locked have unbound latencies, which are completely unrelated to mmap
sem. Other R/W sem users like graphics drivers are not suitable for RT tasks
either.

So there is little risk to hurt RT tasks when the RT rwsem implementation is
done in the following way:

 - Allow concurrent readers

 - Make writers block until the last reader left the critical section. This
   blocking is not subject to priority/budget inheritance.

 - Readers blocked on a writer inherit their priority/budget in the normal
   way.

There is a drawback with this scheme: R/W semaphores become writer unfair
though the applications which have triggered writer starvation (mostly on
mmap_sem) in the past are not really the typical workloads running on a RT
system. So while it's unlikely to hit writer starvation, it's possible. If
there are unexpected workloads on RT systems triggering it, the problem
has to be revisited.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.016885947@linutronix.de
2021-08-17 17:12:47 +02:00
Thomas Gleixner
943f0edb75 locking/rt: Add base code for RT rw_semaphore and rwlock
On PREEMPT_RT, rw_semaphores and rwlocks are substituted with an rtmutex and
a reader count. The implementation is writer unfair, as it is not feasible
to do priority inheritance on multiple readers, but experience has shown
that real-time workloads are not the typical workloads which are sensitive
to writer starvation.

The inner workings of rw_semaphores and rwlocks on RT are almost identical
except for the task state and signal handling. rw_semaphores are not state
preserving over a contention, they are expected to enter and leave with state
== TASK_RUNNING. rwlocks have a mechanism to preserve the state of the task
at entry and restore it after unblocking taking potential non-lock related
wakeups into account. rw_semaphores can also be subject to signal handling
interrupting a blocked state, while rwlocks ignore signals.

To avoid code duplication, provide a shared implementation which takes the
small difference vs. state and signals into account. The code is included
into the relevant rw_semaphore/rwlock base code and compiled for each use
case separately.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.957920571@linutronix.de
2021-08-17 17:12:22 +02:00
Thomas Gleixner
6bc8996add locking/rtmutex: Provide rt_mutex_base_is_locked()
Provide rt_mutex_base_is_locked(), which will be used for various wrapped
locking primitives for RT.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.899572818@linutronix.de
2021-08-17 17:04:35 +02:00
Peter Zijlstra
830e6acc8a locking/rtmutex: Split out the inner parts of 'struct rtmutex'
RT builds substitutions for rwsem, mutex, spinlock and rwlock around
rtmutexes. Split the inner working out so each lock substitution can use
them with the appropriate lockdep annotations. This avoids having an extra
unused lockdep map in the wrapped rtmutex.

No functional change.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.784739994@linutronix.de
2021-08-17 17:04:01 +02:00
Peter Zijlstra
f07ec52202 locking/rtmutex: Remove rt_mutex_is_locked()
There are no more users left.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.552218335@linutronix.de
2021-08-17 17:00:08 +02:00
Thomas Gleixner
2c8bb85151 sched/wake_q: Provide WAKE_Q_HEAD_INITIALIZER()
The RT specific spin/rwlock implementation requires special handling of the
to be woken waiters. Provide a WAKE_Q_HEAD_INITIALIZER(), which can be used by
the rtmutex code to implement an RT aware wake_q derivative.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.429918071@linutronix.de
2021-08-17 16:57:55 +02:00
Thomas Gleixner
6991436c2b sched/core: Provide a scheduling point for RT locks
RT enabled kernels substitute spin/rwlocks with 'sleeping' variants based
on rtmutexes. Blocking on such a lock is similar to preemption versus:

 - I/O scheduling and worker handling, because these functions might block
   on another substituted lock, or come from a lock contention within these
   functions.

 - RCU considers this like a preemption, because the task might be in a read
   side critical section.

Add a separate scheduling point for this, and hand a new scheduling mode
argument to __schedule() which allows, along with separate mode masks, to
handle this gracefully from within the scheduler, without proliferating that
to other subsystems like RCU.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.372319055@linutronix.de
2021-08-17 16:57:17 +02:00
Thomas Gleixner
5f220be214 sched/wakeup: Prepare for RT sleeping spin/rwlocks
Waiting for spinlocks and rwlocks on non RT enabled kernels is task::state
preserving. Any wakeup which matches the state is valid.

RT enabled kernels substitutes them with 'sleeping' spinlocks. This creates
an issue vs. task::__state.

In order to block on the lock, the task has to overwrite task::__state and a
consecutive wakeup issued by the unlocker sets the state back to
TASK_RUNNING. As a consequence the task loses the state which was set
before the lock acquire and also any regular wakeup targeted at the task
while it is blocked on the lock.

To handle this gracefully, add a 'saved_state' member to task_struct which
is used in the following way:

 1) When a task blocks on a 'sleeping' spinlock, the current state is saved
    in task::saved_state before it is set to TASK_RTLOCK_WAIT.

 2) When the task unblocks and after acquiring the lock, it restores the saved
    state.

 3) When a regular wakeup happens for a task while it is blocked then the
    state change of that wakeup is redirected to operate on task::saved_state.

    This is also required when the task state is running because the task
    might have been woken up from the lock wait and has not yet restored
    the saved state.

To make it complete, provide the necessary helpers to save and restore the
saved state along with the necessary documentation how the RT lock blocking
is supposed to work.

For non-RT kernels there is no functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.258751046@linutronix.de
2021-08-17 16:49:02 +02:00
Thomas Gleixner
85019c1674 sched/wakeup: Reorganize the current::__state helpers
In order to avoid more duplicate implementations for the debug and
non-debug variants of the state change macros, split the debug portion out
and make that conditional on CONFIG_DEBUG_ATOMIC_SLEEP=y.

Suggested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.200898048@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-08-17 16:45:28 +02:00
Thomas Gleixner
cd781d0ce8 sched/wakeup: Introduce the TASK_RTLOCK_WAIT state bit
RT kernels have an extra quirk for try_to_wake_up() to handle task state
preservation across periods of blocking on a 'sleeping' spin/rwlock.

For this to function correctly and under all circumstances try_to_wake_up()
must be able to identify whether the wakeup is lock related or not and
whether the task is waiting for a lock or not.

The original approach was to use a special wake_flag argument for
try_to_wake_up() and just use TASK_UNINTERRUPTIBLE for the tasks wait state
and the try_to_wake_up() state argument.

This works in principle, but due to the fact that try_to_wake_up() cannot
determine whether the task is waiting for an RT lock wakeup or for a regular
wakeup it's suboptimal.

RT kernels save the original task state when blocking on an RT lock and
restore it when the lock has been acquired. Any non lock related wakeup is
checked against the saved state and if it matches the saved state is set to
running so that the wakeup is not lost when the state is restored.

While the necessary logic for the wake_flag based solution is trivial, the
downside is that any regular wakeup with TASK_UNINTERRUPTIBLE in the state
argument set will wake the task despite the fact that it is still blocked
on the lock. That's not a fatal problem as the lock wait has do deal with
spurious wakeups anyway, but it introduces unnecessary latencies.

Introduce the TASK_RTLOCK_WAIT state bit which will be set when a task
blocks on an RT lock.

The lock wakeup will use wake_up_state(TASK_RTLOCK_WAIT), so both the
waiting state and the wakeup state are distinguishable, which avoids
spurious wakeups and allows better analysis.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.144989915@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-08-17 16:45:15 +02:00
Thomas Gleixner
b41cda0376 locking/rtmutex: Set proper wait context for lockdep
RT mutexes belong to the LD_WAIT_SLEEP class. Make them so.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.031014562@linutronix.de
2021-08-17 16:38:50 +02:00
Thomas Gleixner
d8bbd97ad0 locking/local_lock: Add missing owner initialization
If CONFIG_DEBUG_LOCK_ALLOC=y is enabled then local_lock_t has an 'owner'
member which is checked for consistency, but nothing initialized it to
zero explicitly.

The static initializer does so implicit, and the run time allocated per CPU
storage is usually zero initialized as well, but relying on that is not
really good practice.

Fixes: 91710728d1 ("locking: Introduce local_lock()")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211301.969975279@linutronix.de
2021-08-17 16:38:40 +02:00
Ingo Molnar
c87866ede4 Linux 5.14-rc6
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Merge tag 'v5.14-rc6' into locking/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-08-17 16:16:29 +02:00
Sebastian Krzyszkowiak
4bf00434a6 power: supply: max17042_battery: more robust chip type checks
Prepared by checking the datasheets of max17042, max17047/50
and max170455 for differences in register maps.

Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2021-08-17 15:33:52 +02:00
Sebastian Krzyszkowiak
ed0d0a0506 power: supply: max17042_battery: fix typo in MAx17042_TOFF
Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2021-08-17 15:33:52 +02:00
Sebastian Krzyszkowiak
1e4f30eaf4 power: supply: max17042_battery: clean up MAX17055_V_empty
This register is same as in MAX17047 and MAX17050, so there's no need
for custom casing it.

Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2021-08-17 15:33:52 +02:00
Amir Goldstein
4f911138c8 fs: add generic helper for filling statx attribute flags
The immutable and append-only properties on an inode are published on
the inode's i_flags and enforced by the VFS.

Create a helper to fill the corresponding STATX_ATTR_ flags in the kstat
structure from the inode's i_flags.

Only orange was converted to use this helper.
Other filesystems could use it in the future.

Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-17 11:47:43 +02:00
Christoph Hellwig
fad0a1ab34 iomap: constify iomap_iter_srcmap
The srcmap returned from iomap_iter_srcmap is never modified, so mark
the iomap returned from it const and constify a lot of code that never
modifies the iomap.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-16 21:26:33 -07:00
Christoph Hellwig
b74b1293e6 iomap: rework unshare flag
Instead of another internal flags namespace inside of buffered-io.c,
just pass a UNSHARE hint in the main iomap flags field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-16 21:26:33 -07:00
Christoph Hellwig
57320a01fe iomap: remove iomap_apply
iomap_apply is unused now, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[djwong: rebase this patch to preserve git history of iomap loop control]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-08-16 21:26:33 -07:00
Christoph Hellwig
a6d3d49587 iomap: switch __iomap_dio_rw to use iomap_iter
Switch __iomap_dio_rw to use iomap_iter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-16 21:26:33 -07:00