Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH v2 1/3] locking: Document the semantics of spin_is_locked() | Date | Tue, 03 Apr 2018 22:43:14 +0100 |
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Alan Stern <stern@rowland.harvard.edu> wrote:
> + * Returns: 1 if @lock is locked, 0 otherwise. > + * However, on !CONFIG_SMP builds with !CONFIG_DEBUG_SPINLOCK, > + * the return value is always 0 (see include/linux/spinlock_up.h). > + * Therefore you should not rely heavily on the return value.
Seems reasonable.
It might also want to include a note that the lock isn't necessarily held by your own CPU. I would also use "=n" rather than "!", so maybe something like:
* Returns: 1 if @lock is locked, 0 otherwise. * * Note that the function only tells you that the CPU is seen to be locked, * not that it is locked on your CPU. * * Further, on CONFIG_SMP=n builds with CONFIG_DEBUG_SPINLOCK=n, the return * value is always 0 (see include/linux/spinlock_up.h). Therefore you should * not rely heavily on the return value.
David
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