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2017-06-28locking/refcount: Create unchecked atomic_t implementationKees Cook
Many subsystems will not use refcount_t unless there is a way to build the kernel so that there is no regression in speed compared to atomic_t. This adds CONFIG_REFCOUNT_FULL to enable the full refcount_t implementation which has the validation but is slightly slower. When not enabled, refcount_t uses the basic unchecked atomic_t routines, which results in no code changes compared to just using atomic_t directly. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: David Windsor <dwindsor@gmail.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Hans Liljestrand <ishkamiel@gmail.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Jann Horn <jannh@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: arozansk@redhat.com Cc: axboe@kernel.dk Cc: linux-arch <linux-arch@vger.kernel.org> Link: http://lkml.kernel.org/r/20170621200026.GA115679@beast Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-06refcount: change EXPORT_SYMBOL markingsGreg Kroah-Hartman
Now that kref is using the refcount apis, the _GPL markings are getting exported to places that it previously wasn't. Now kref.h is GPLv2 licensed, so any non-GPL code using it better be talking to some lawyers, but changing api markings isn't considered "nice", so let's fix this up. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-23locking/refcounts: Use atomic_try_cmpxchg()Peter Zijlstra
Generates better code (GCC-6.2.1): text filename 1576 defconfig-build/lib/refcount.o.pre 1488 defconfig-build/lib/refcount.o.post Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.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: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-13locking/refcount: Add refcount_t API kernel-doc commentsDavid Windsor
Signed-off-by: David Windsor <dwindsor@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: elena.reshetova@intel.com Cc: kernel-hardening@lists.openwall.com Link: http://lkml.kernel.org/r/1489160052-20293-1-git-send-email-dwindsor@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-01locking/refcounts: Change WARN() to WARN_ONCE()Ingo Molnar
Linus noticed that the new refcount.h APIs used WARN(), which would turn into a dmesg DoS if it triggers frequently on some buggy driver. So make sure we only warn once. These warnings are never supposed to happen, so it's typically not a problem to lose subsequent warnings. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/CA+55aFzbYUTZ=oqZ2YgDjY0C2_n6ODhTfqj6V+m5xWmDxsuB0w@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-24locking/refcounts: Out-of-line everythingPeter Zijlstra
Linus asked to please make this real C code. And since size then isn't an issue what so ever anymore, remove the debug knob and make all WARN()s unconditional. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dwindsor@gmail.com Cc: elena.reshetova@intel.com Cc: gregkh@linuxfoundation.org Cc: ishkamiel@gmail.com Cc: keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>