On Wed, Jul 09, 2014 at 01:12:17PM +0200, Hannes Reinecke wrote: > Hmm. I guess there is a race window between > atomic_read() and atomic_set(). > Doesn't this cause issues when someone calls atomic_set() just before the > call to atomic_read? There is a race window just _after_ the atomic_read, but it's harmless. The whole _blocked scheme is a backoff to avoid resubmitting I/O all the time when the HBA or target returned a busy status. If we race an incorrectly reset it we will submit I/O and just get a busy indicator again. On the other hand doing the atomic_set all the time introduces three atomic in the I/O completion part that are entirely pointless most of the time. I guess I should add something like this as a comment to the code.. Note that the old code didn't use any sort of synchronization either. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
