NVMe: Rename io_timeout to nvme_io_timeout

It's positively immoral to have a global variable called 'io_timeout'.
Keep the module parameter called io_timeout, though.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

drivers/block/nvme-core.c

@@ -54,8 +54,8 @@ static unsigned char admin_timeout = 60;
 module_param(admin_timeout, byte, 0644);
 MODULE_PARM_DESC(admin_timeout, "timeout in seconds for admin commands");
 
-unsigned char io_timeout = 30;
-module_param(io_timeout, byte, 0644);
+unsigned char nvme_io_timeout = 30;
+module_param_named(io_timeout, nvme_io_timeout, byte, 0644);
 MODULE_PARM_DESC(io_timeout, "timeout in seconds for I/O");
 
 static unsigned char retry_time = 30;

include/linux/nvme.h

@@ -62,8 +62,8 @@ enum {
 
 #define NVME_VS(major, minor)	(major << 16 | minor)
 
-extern unsigned char io_timeout;
-#define NVME_IO_TIMEOUT	(io_timeout * HZ)
+extern unsigned char nvme_io_timeout;
+#define NVME_IO_TIMEOUT	(nvme_io_timeout * HZ)
 
 /*
  * Represents an NVM Express device.  Each nvme_dev is a PCI function.