kernel/Documentation/core-api/refcount-vs-atomic.rst, branch linux-5.1.y

refcount_t: Add ACQUIRE ordering on success for dec(sub)_and_test() variants

2019-02-04T08:03:31Z

This adds an smp_acquire__after_ctrl_dep() barrier on successful decrease of refcounter value from 1 to 0 for refcount_dec(sub)_and_test variants and therefore gives stronger memory ordering guarantees than prior versions of these functions. Co-developed-by: Peter Zijlstra (Intel) Signed-off-by: Elena Reshetova Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Andrea Parri Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: dvyukov@google.com Cc: keescook@chromium.org Cc: stern@rowland.harvard.edu Link: https://lkml.kernel.org/r/1548847131-27854-2-git-send-email-elena.reshetova@intel.com Signed-off-by: Ingo Molnar

Documentation: refcount-vs-atomic: Update reference to LKMM doc.

2018-05-08T20:52:39Z

The LKMM project has moved to 'tools/memory-model/'. Signed-off-by: Andrea Parri Signed-off-by: Jonathan Corbet

docs: refcount_t documentation

2017-12-11T21:37:11Z

Some functions from refcount_t API provide different memory ordering guarantees that their atomic counterparts. This adds a document outlining these differences ( Documentation/core-api/refcount-vs-atomic.rst) as well as some other minor improvements. Signed-off-by: Elena Reshetova Signed-off-by: Kees Cook Signed-off-by: Jonathan Corbet