nvme-scsi: Consider LBA format in IO splitting calculation

The current command submission code uses a sector-based value when
considering the maximum number of blocks per command. With a
4k-formatted namespace and a command exceeding max hardware limits, this
calculation doesn't split IOs which should be split and fails in the
nvme layer. This patch fixes that calculation and enables IO splitting
in these circumstances.
Signed-off-by: NJon Derrick <jonathan.derrick@intel.com>
Reviewed-by: NJens Axboe <axboe@fb.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/nvme/host/scsi.c

@@ -1609,7 +1609,7 @@ static int nvme_trans_do_nvme_io(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 	struct nvme_command c;
 	u8 opcode = (is_write ? nvme_cmd_write : nvme_cmd_read);
 	u16 control;
-	u32 max_blocks = queue_max_hw_sectors(ns->queue);
+	u32 max_blocks = queue_max_hw_sectors(ns->queue) >> (ns->lba_shift - 9);
 
 	num_cmds = nvme_trans_io_get_num_cmds(hdr, cdb_info, max_blocks);