Hi Martin, This code was added to detect holes, when we started testing with 4.9 kernel. when we disabled "use_blk_mq" and no merges, we are hitting issues with holes. Anyhow In latest upstream, it got fixed with this commit 5a8d75a1b8c99bdc926ba69b7b7dbe4fae81a5af So we are removing the code related to hole detection . Thanks, Suganath Prabu S On Tue, Aug 8, 2017 at 9:42 PM, Martin K. Petersen <martin.petersen@xxxxxxxxxx> wrote: > > Suganath, > >> + /* >> + ** Below code detects gaps/holes in IO data buffers. >> + ** What does holes/gaps mean? >> + ** Any SGE except first one in a SGL starts at non NVME page size >> + ** aligned address OR Any SGE except last one in a SGL ends at >> + ** non NVME page size boundary. >> + ** >> + ** Driver has already informed block layer by setting boundary rules >> + ** for bio merging done at NVME page size boundary calling kernel API >> + ** blk_queue_virt_boundary inside slave_config. >> + ** Still there is possibility of IO coming with holes to driver because >> + ** of IO merging done by IO scheduler. > > All this SGL to PRP code needs to go. > > If you are seeing anything that's not a valid PRP after setting the > queue virt boundary then there's a block layer bug that needs to be > debugged and fixed. Regardless of whether you are using an I/O scheduler > or not. > > -- > Martin K. Petersen Oracle Linux Engineering
