linux-toradex.git/include/linux/mutex.h, branch v5.14-rc6

Merge tag 'v5.12-rc5' into locking/core, to pick up fixes

2021-03-29T13:56:48+00:00

Signed-off-by: Ingo Molnar

locking/mutex: Remove repeated declaration

2021-03-25T11:02:06+00:00

Commit 0cd39f4600ed ("locking/seqlock, headers: Untangle the spaghetti monster")
introduces 'struct ww_acquire_ctx' again, remove the repeated declaration and move
the pre-declarations to the top.

Signed-off-by: Shaokun Zhang 
Signed-off-by: Ingo Molnar 
Acked-by: Waiman Long 
Link: https://lore.kernel.org/r/1616564440-61318-1-git-send-email-zhangshaokun@hisilicon.com

locking/mutex: Fix non debug version of mutex_lock_io_nested()

2021-03-23T11:20:23+00:00

If CONFIG_DEBUG_LOCK_ALLOC=n then mutex_lock_io_nested() maps to
mutex_lock() which is clearly wrong because mutex_lock() lacks the
io_schedule_prepare()/finish() invocations.

Map it to mutex_lock_io().

Fixes: f21860bac05b ("locking/mutex, sched/wait: Fix the mutex_lock_io_nested() define")
Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/878s6fshii.fsf@nanos.tec.linutronix.de

locking/mutex: Kill mutex_trylock_recursive()

2021-02-10T13:44:40+00:00

There are not users of mutex_trylock_recursive() in tree as of
v5.11-rc7.

Remove it.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20210210085248.219210-2-bigeasy@linutronix.de

locking/seqlock, headers: Untangle the spaghetti monster

2020-08-06T14:13:13+00:00

By using lockdep_assert_*() from seqlock.h, the spaghetti monster
attacked.

Attack back by reducing seqlock.h dependencies from two key high level headers:

 - :               -Remove 
 - :                  -Remove 
 - :                 +Add    

The price was to add it to sched.h ...

Core header fallout, we add direct header dependencies instead of gaining them
parasitically from higher level headers:

 - :  +Add 
 - :               +Add 
 - :                 +Add 
 - :               +Add 
 - :                 +Add 
 - :             +Add 

Arch headers fallout:

 - PARISC: :           +Add 
 - SH:     :              +Add 
 - SPARC:  :        +Add 
 - SPARC:  :            +Add , 
                                    -Remove 
 - X86:    :          +Add 
                                    -Remove 

There's also a bunch of parasitic header dependency fallout in .c files, not listed
separately.

[ mingo: Extended the changelog, split up & fixed the original patch. ]

Co-developed-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20200804133438.GK2674@hirez.programming.kicks-ass.net

lockdep: Introduce wait-type checks

2020-03-21T15:00:24+00:00

Extend lockdep to validate lock wait-type context.

The current wait-types are:

	LD_WAIT_FREE,		/* wait free, rcu etc.. */
	LD_WAIT_SPIN,		/* spin loops, raw_spinlock_t etc.. */
	LD_WAIT_CONFIG,		/* CONFIG_PREEMPT_LOCK, spinlock_t etc.. */
	LD_WAIT_SLEEP,		/* sleeping locks, mutex_t etc.. */

Where lockdep validates that the current lock (the one being acquired)
fits in the current wait-context (as generated by the held stack).

This ensures that there is no attempt to acquire mutexes while holding
spinlocks, to acquire spinlocks while holding raw_spinlocks and so on. In
other words, its a more fancy might_sleep().

Obviously RCU made the entire ordeal more complex than a simple single
value test because RCU can be acquired in (pretty much) any context and
while it presents a context to nested locks it is not the same as it
got acquired in.

Therefore its necessary to split the wait_type into two values, one
representing the acquire (outer) and one representing the nested context
(inner). For most 'normal' locks these two are the same.

[ To make static initialization easier we have the rule that:
  .outer == INV means .outer == .inner; because INV == 0. ]

It further means that its required to find the minimal .inner of the held
stack to compare against the outer of the new lock; because while 'normal'
RCU presents a CONFIG type to nested locks, if it is taken while already
holding a SPIN type it obviously doesn't relax the rules.

Below is an example output generated by the trivial test code:

  raw_spin_lock(&foo);
  spin_lock(&bar);
  spin_unlock(&bar);
  raw_spin_unlock(&foo);

 [ BUG: Invalid wait context ]
 -----------------------------
 swapper/0/1 is trying to lock:
 ffffc90000013f20 (&bar){....}-{3:3}, at: kernel_init+0xdb/0x187
 other info that might help us debug this:
 1 lock held by swapper/0/1:
  #0: ffffc90000013ee0 (&foo){+.+.}-{2:2}, at: kernel_init+0xd1/0x187

The way to read it is to look at the new -{n,m} part in the lock
description; -{3:3} for the attempted lock, and try and match that up to
the held locks, which in this case is the one: -{2,2}.

This tells that the acquiring lock requires a more relaxed environment than
presented by the lock stack.

Currently only the normal locks and RCU are converted, the rest of the
lockdep users defaults to .inner = INV which is ignored. More conversions
can be done when desired.

The check for spinlock_t nesting is not enabled by default. It's a separate
config option for now as there are known problems which are currently
addressed. The config option allows to identify these problems and to
verify that the solutions found are indeed solving them.

The config switch will be removed and the checks will permanently enabled
once the vast majority of issues has been addressed.

[ bigeasy: Move LD_WAIT_FREE,… out of CONFIG_LOCKDEP to avoid compile
	   failure with CONFIG_DEBUG_SPINLOCK + !CONFIG_LOCKDEP]
[ tglx: Add the config option ]

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20200321113242.427089655@linutronix.de

mutex: Fix up mutex_waiter usage

2019-08-08T07:09:25+00:00

The patch moving bits into mutex.c was a little too much; by also
moving struct mutex_waiter a few less common CONFIGs would no longer
build.

Fixes: 5f35d5a66b3e ("locking/mutex: Make __mutex_owner static to mutex.c")
Signed-off-by: Peter Zijlstra (Intel)

locking/mutex: Make __mutex_owner static to mutex.c

2019-08-06T10:49:16+00:00

__mutex_owner() should only be used by the mutex api's.
So, to put this restiction let's move the __mutex_owner()
function definition from linux/mutex.h to mutex.c file.

There exist functions that uses __mutex_owner() like
mutex_is_locked() and mutex_trylock_recursive(), So
to keep legacy thing intact move them as well and
export them.

Move mutex_waiter structure also to keep it private to the
file.

Signed-off-by: Mukesh Ojha 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: mingo@redhat.com
Cc: will@kernel.org
Link: https://lkml.kernel.org/r/1564585504-3543-1-git-send-email-mojha@codeaurora.org

docs: locking: convert docs to ReST and rename to *.rst

2019-07-15T11:53:27+00:00

Convert the locking documents to ReST and add them to the
kernel development book where it belongs.

Most of the stuff here is just to make Sphinx to properly
parse the text file, as they're already in good shape,
not requiring massive changes in order to be parsed.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab 
Acked-by: Federico Vaga

locking/spinlocks: Clean up comment and #ifndef for {,queued_}spin_is_locked()

2018-05-15T06:11:15+00:00

Removes "#ifndef queued_spin_is_locked" from the generic code: this is
unused and it's reasonable to conclude that it will continue to be unused.

Also removes the comment about spin_is_locked() from mutex_is_locked():
the comment remains valid but not particularly useful.

Suggested-by: Will Deacon 
Signed-off-by: Andrea Parri 
Signed-off-by: Paul E. McKenney 
Acked-by: Will Deacon 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: stern@rowland.harvard.edu
Link: http://lkml.kernel.org/r/1526338889-7003-3-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar