Messages in this thread | | | Subject | Re: Further copy_from_user() discussion. | From | Catalin Marinas <> | Date | Thu, 14 Apr 2005 10:36:47 +0100 |
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Vadim Lobanov <vlobanov@speakeasy.net> wrote: > 2. Would it be possible to eliminate the might_sleep() call in > copy_from_user()? It seems that, very soon after, the __copy_from_user() > macro does another might_sleep(), with very few instructions in between. > But there might be some trick here that I'm missing.
might_sleep() is used for debugging the possible sleep while in an atomic operation. I think it is safe to check this for all the calls to copy_from_user(), no matter if the access is OK or not (memset being used in the latter case). The same is for __copy_from_user(). Anyway, if you don't enable CONFIG_DEBUG_SPINLOCK_SLEEP, the might_sleep() macro is empty.
-- Catalin
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