On Wed, 2011-05-18 at 09:35 -0600, Moore, Eric wrote: > I worked the original defect a couple months ago, and Kashyap is now > getting around to posting my patch's. > > This original defect has nothing to do with PPC64. The original > problem was only on x86. It only became a problem on PPC64 when I > tried to fix the original x86 issue by copying the writeq code from > the linux headers, then it broke PPC64. I doubt that broken patch > was ever posted. Anyways, back to the original defect. The reason it > because a problem for x86 is because the kernel headers had a > implementation of writeq in the arch/x86 headers, which means our > internal implementation of writeq is not being used. The writeq > implementation in the kernel is total wrong for arch/x86 because it > doesn't not have spin locks, and if two processor simultaneously doing > two separate 32bit pci writes, then what is received by controller > firmware is out of order. This change occurs between Red Hat RHEL5 > and RHEL6. In RHEL5, this writeq was not implemented in arch/x86 > headers, and our driver internal implementation of write was used. You may also want to look at Milton's comments, it looks like the way you do init_completion followed immediately by wait_completion is racy. You should init the completion before you do the IO that will eventually trigger complete() to be called. Cheers, Ben. -- 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
