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13 commits

Author SHA1 Message Date
Mark Rutland
00b808ab79 atomics/generic: Define atomic64_fetch_add_unless()
As a step towards unifying the atomic/atomic64/atomic_long APIs, this
patch converts the generic implementation of atomic64_add_unless() into
a generic implementation of atomic64_fetch_add_unless().

A wrapper in <linux/atomic.h> will build atomic_add_unless() atop of
this, provided it is given a preprocessor definition.

No functional change is intended as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-9-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21 14:25:21 +02:00
Mark Rutland
ade5ef9280 atomics: Make conditional ops return 'bool'
Some of the atomics return a status value, which is a boolean value
describing whether the operation was performed. To make it clear that
this is a boolean value, let's update the common fallbacks to return
bool, fixing up the return values and comments likewise.

At the same time, let's simplify the description of the operations in
their respective comments.

The instrumented atomics and generic atomic64 implementation are updated
accordingly.

Note that atomic64_dec_if_positive() doesn't follow the usual test op
pattern, and returns the would-be decremented value. This is not
changed.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-5-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21 14:22:33 +02:00
Peter Zijlstra
28aa2bda22 locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()
Now that all the architectures have implemented support for these new
atomic primitives add on the generic infrastructure to expose and use
it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-16 10:48:32 +02:00
Peter Zijlstra
e6942b7de2 atomic: Provide atomic_{or,xor,and}
Implement atomic logic ops -- atomic_{or,xor,and}.

These will replace the atomic_{set,clear}_mask functions that are
available on some archs.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-27 14:06:24 +02:00
Peter Zijlstra
560cb12a40 locking,arch: Rewrite generic atomic support
Rewrite generic atomic support to only require cmpxchg(), generate all
other primitives from that.

Furthermore reduce the endless repetition for all these primitives to
a few CPP macros. This way we get more for less lines.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140508135852.940119622@infradead.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-14 12:48:14 +02:00
Stephen Boyd
fcc16882ac lib: atomic64: Initialize locks statically to fix early users
The atomic64 library uses a handful of static spin locks to implement
atomic 64-bit operations on architectures without support for atomic
64-bit instructions.

Unfortunately, the spinlocks are initialized in a pure initcall and that
is too late for the vfs namespace code which wants to use atomic64
operations before the initcall is run.

This became a problem as of commit 8823c079ba: "vfs: Add setns support
for the mount namespace".

This leads to BUG messages such as:

  BUG: spinlock bad magic on CPU#0, swapper/0/0
   lock: atomic64_lock+0x240/0x400, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
    do_raw_spin_lock+0x158/0x198
    _raw_spin_lock_irqsave+0x4c/0x58
    atomic64_add_return+0x30/0x5c
    alloc_mnt_ns.clone.14+0x44/0xac
    create_mnt_ns+0xc/0x54
    mnt_init+0x120/0x1d4
    vfs_caches_init+0xe0/0x10c
    start_kernel+0x29c/0x300

coming out early on during boot when spinlock debugging is enabled.

Fix this by initializing the spinlocks statically at compile time.

Reported-and-tested-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-20 13:50:16 -08:00
Paul Gortmaker
8bc3bcc93a lib: reduce the use of module.h wherever possible
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-07 15:04:04 -05:00
Yong Zhang
cb475de3d1 lib: atomic64: Change the type of local lock to raw_spinlock_t
There are still some leftovers of commit f59ca058
[locking, lib/atomic64: Annotate atomic64_lock::lock as raw]

[ tglx: Seems I picked the wrong version of that patch :( ]

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shan Hai <haishan.bai@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20110914074924.GA16096@zhy
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-09-14 13:14:11 +02:00
Shan Hai
f59ca05871 locking, lib/atomic64: Annotate atomic64_lock::lock as raw
The spinlock protected atomic64 operations must be irq safe as they
are used in hard interrupt context and cannot be preempted on -rt:

 NIP [c068b218] rt_spin_lock_slowlock+0x78/0x3a8
  LR [c068b1e0] rt_spin_lock_slowlock+0x40/0x3a8
 Call Trace:
  [eb459b90] [c068b1e0] rt_spin_lock_slowlock+0x40/0x3a8 (unreliable)
  [eb459c20] [c068bdb0] rt_spin_lock+0x40/0x98
  [eb459c40] [c03d2a14] atomic64_read+0x48/0x84
  [eb459c60] [c001aaf4] perf_event_interrupt+0xec/0x28c
  [eb459d10] [c0010138] performance_monitor_exception+0x7c/0x150
  [eb459d30] [c0014170] ret_from_except_full+0x0/0x4c

So annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Shan Hai <haishan.bai@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-13 11:12:22 +02:00
Arun Sharma
60063497a9 atomic: use <linux/atomic.h>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 16:49:47 -07:00
Luca Barbieri
97577896f6 lib: Fix atomic64_add_unless return value convention
atomic64_add_unless must return 1 if it perfomed the add and 0 otherwise.
The generic implementation did the opposite thing.

Reported-by: H. Peter Anvin <hpa@zytor.com>
Confirmed-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267469749-11878-4-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-03-01 11:38:46 -08:00
Roland Dreier
3fc7b4b220 lib: export generic atomic64_t functions
The generic atomic64_t implementation in lib/ did not export the functions
it defined, which means that modules that use atomic64_t would not link on
platforms (such as 32-bit powerpc).  For example, trying to build a kernel
with CONFIG_NET_RDS on such a platform would fail with:

    ERROR: "atomic64_read" [net/rds/rds.ko] undefined!
    ERROR: "atomic64_set" [net/rds/rds.ko] undefined!

Fix this by exporting the atomic64_t functions to modules.  (I export the
entire API even if it's not all currently used by in-tree modules to avoid
having to continue fixing this in dribs and drabs)

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-29 19:10:35 -07:00
Paul Mackerras
09d4e0edd4 lib: Provide generic atomic64_t implementation
Many processor architectures have no 64-bit atomic instructions, but
we need atomic64_t in order to support the perf_counter subsystem.

This adds an implementation of 64-bit atomic operations using hashed
spinlocks to provide atomicity.  For each atomic operation, the address
of the atomic64_t variable is hashed to an index into an array of 16
spinlocks.  That spinlock is taken (with interrupts disabled) around the
operation, which can then be coded non-atomically within the lock.

On UP, all the spinlock manipulation goes away and we simply disable
interrupts around each operation.  In fact gcc eliminates the whole
atomic64_lock variable as well.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-06-15 13:27:38 +10:00