NVMe: Make I/O timeout a module parameter

Increase the default timeout to 30 seconds to match SCSI.

Signed-off-by: Keith Busch <keith.busch@intel.com>
[use byte instead of ushort]
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

drivers/block/nvme-core.c

@@ -50,6 +50,10 @@
 #define CQ_SIZE(depth)		(depth * sizeof(struct nvme_completion))
 #define ADMIN_TIMEOUT	(60 * HZ)
 
+unsigned char io_timeout = 30;
+module_param(io_timeout, byte, 0644);
+MODULE_PARM_DESC(io_timeout, "timeout in seconds for I/O");
+
 static int nvme_major;
 module_param(nvme_major, int, 0);