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 13:49:09 +0100 |
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Andrea Parri <andrea.parri@amarulasolutions.com> wrote:
> +/** > + * spin_is_locked() - Check whether a spinlock is locked. > + * @lock: Pointer to the spinlock. > + * > + * This function is NOT required to provide any memory ordering > + * guarantees; it could be used for debugging purposes or, when > + * additional synchronization is needed, accompanied with other > + * constructs (memory barriers) enforcing the synchronization. > + * > + * Return: 1, if @lock is (found to be) locked; 0, otherwise.
It's more complicated than that. This function is dangerous and should be used with extreme care. In the case where CONFIG_SMP=n the value is locked one way or the other and it might be the wrong way.
David
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