Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1530174
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() |
| Date | 2016-11-25 13:50 +0100 |
| Message-ID | <sHo6Z-CC-5@gated-at.bofh.it> (permalink) |
| References | <sGZrY-1oP-13@gated-at.bofh.it> <sH8Yh-7HV-5@gated-at.bofh.it> <sHmRA-8kF-1@gated-at.bofh.it> <sHn1g-8nO-21@gated-at.bofh.it> <sHnND-wd-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Nov 25, 2016 at 12:23:56PM +0000, Mark Rutland wrote:
> Naming will be problematic; calling them ATOMIC_* makes tham sound like
> they work on atomic_t. That and I have no idea how to ensure correct
> usage tree-wide; I'm not sure if/how Coccinelle can help.
>
> Peter, thoughts?
Something like so perhaps?
---
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
#define WARN_SINGLE_COPY_ALIGNMENT(ptr) \
WARN_ON_ONCE(((unsigned long)(ptr)) & (sizeof(*(ptr))-1))
#else
#define WARN_SINGLE_COPY_ALIGNMENT(ptr)
#endif
/*
* Provide accessors for Single-Copy atomicy.
*
* That is, ensure that machine word sized loads/stores to naturally
* aligned variables are single instructions.
*
* By reason of not being able to use C11 atomic crud, use our beloved
* volatile qualifier. Since volatile tells the compiler the value can
* be changed behind its back, it must use Single-Copy atomic loads and
* stores to access them, otherwise it runs the risk of load/store
* tearing.
*/
#define SINGLE_LOAD(x) \
{( \
compiletime_assert_atomic_type(typeof(x)); \
WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
READ_ONCE(x); \
})
#define SINGLE_STORE(x, v) \
({ \
compiletime_assert_atomic_type(typeof(x)); \
WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
WRITE_ONCE(x, v); \
})
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-24 11:30 +0100
[PATCH 2/3] vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-24 11:30 +0100
Re: [PATCH 2/3] vringh: kill off ACCESS_ONCE() Christian Borntraeger <borntraeger@de.ibm.com> - 2016-11-24 12:20 +0100
Re: [PATCH 2/3] vringh: kill off ACCESS_ONCE() Cornelia Huck <cornelia.huck@de.ibm.com> - 2016-11-24 12:40 +0100
Re: [PATCH 2/3] vringh: kill off ACCESS_ONCE() Jason Wang <jasowang@redhat.com> - 2016-11-25 03:50 +0100
[PATCH 1/3] tools/virtio: fix READ_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-24 11:30 +0100
Re: [PATCH 1/3] tools/virtio: fix READ_ONCE() Cornelia Huck <cornelia.huck@de.ibm.com> - 2016-11-24 12:40 +0100
Re: [PATCH 1/3] tools/virtio: fix READ_ONCE() Jason Wang <jasowang@redhat.com> - 2016-11-25 03:40 +0100
[PATCH 3/3] tools/virtio: use {READ,WRITE}_ONCE() in uaccess.h Mark Rutland <mark.rutland@arm.com> - 2016-11-24 11:30 +0100
Re: [PATCH 3/3] tools/virtio: use {READ,WRITE}_ONCE() in uaccess.h Cornelia Huck <cornelia.huck@de.ibm.com> - 2016-11-24 12:40 +0100
Re: [PATCH 3/3] tools/virtio: use {READ,WRITE}_ONCE() in uaccess.h Jason Wang <jasowang@redhat.com> - 2016-11-25 03:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() "Michael S. Tsirkin" <mst@redhat.com> - 2016-11-24 21:40 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 12:30 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Christian Borntraeger <borntraeger@de.ibm.com> - 2016-11-25 12:40 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 13:30 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Peter Zijlstra <peterz@infradead.org> - 2016-11-25 13:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Peter Zijlstra <peterz@infradead.org> - 2016-11-25 13:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Boqun Feng <boqun.feng@gmail.com> - 2016-11-25 16:00 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Dmitry Vyukov <dvyukov@google.com> - 2016-11-25 16:30 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 17:20 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Peter Zijlstra <peterz@infradead.org> - 2016-11-25 17:20 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 17:40 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Christian Borntraeger <borntraeger@de.ibm.com> - 2016-11-25 18:00 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 18:30 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Peter Zijlstra <peterz@infradead.org> - 2016-11-25 18:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Christian Borntraeger <borntraeger@de.ibm.com> - 2016-11-25 19:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() "Michael S. Tsirkin" <mst@redhat.com> - 2016-11-25 22:10 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Christian Borntraeger <borntraeger@de.ibm.com> - 2016-11-25 22:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Dmitry Vyukov <dvyukov@google.com> - 2016-11-25 18:30 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 18:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Linus Torvalds <torvalds@linux-foundation.org> - 2016-11-25 19:00 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 19:10 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Linus Torvalds <torvalds@linux-foundation.org> - 2016-11-25 19:50 +0100
Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() Mark Rutland <mark.rutland@arm.com> - 2016-11-25 15:40 +0100
csiph-web