On 2020/1/24 6:54, Jason Gunthorpe wrote: > On Wed, Jan 22, 2020 at 04:54:55PM +0800, Weihang Li wrote: >> >> >> On 2020/1/17 3:51, Jason Gunthorpe wrote: >>>>> What happens to your userspace if it runs on an old kernel and tries >>>>> to use extended atomic? >>>>> >>>>> Jason >>>>> >>>> Hi Jason, >>>> >>>> If the hns userspace runs with old kernel, the hardware will report a asynchronous >>>> event for the extended atomic operation and modify the qp to error state because >>>> the enable bit in this qp's context hasn't been set. >>>> >>>> The driver will print like this: >>>> >>>> [ 1252.240921] hns3 0000:7d:00.0: Invalid request local work queue 0x9 error. >>>> [ 1252.247772] hns3 0000:7d:00.0: no hr_qp can be found! >>> Ideally the provider will not set >>> IBV_PCI_ATOMIC_OPERATION_4_BYTE_SIZE_SUP and related without kernel >>> support.. >>> >>> I've applied this patch, but I feel like you may need a followup to >>> fix the capability reporting? >>> >>> Jason >> >> Hi Jason, >> >> Thank for your suggestions. >> >> But I'm confuse about the relationship between "PCI ATOMIC" in this macro >> and atomic operations in RDMA. >> >> I found the related series on patchwork: >> https://patchwork.kernel.org/cover/10782873/ > > I may have got the wrong capability bit here, I'm not sure where the > capability bits for extended atomics are actually > > Jason Hi Jason, Thank you anyway. There seems no capability bit for extended atomic currently. We will try to add one. Weihang >
