> I missed the fact the clear_bit is not atomic. So to make this > complete I will send a new patch with protection on the clear bit. > Would you like me to send a patch for user_mad too or would you push > that?
Hmm, actually maybe clear_bit is atomic enough for us. <asm-generic/atmoic.h> says: * clear_bit() is atomic and may not be reordered. However, it does * not contain a memory barrier, so if it is used for locking purposes, * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() * in order to ensure changes are visible on other processors. and I don't think we have an issue with visibility of the updates -- the worst case I guess is a tiny window where we fail to register a new device just as we are unregistering another device on a different CPU. I guess I knew that already once long ago, and so that's why there isn't locking around the clear_bit parts of things. - R. -- Roland Dreier <rola...@cisco.com> || For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/index.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
