NVMe: Change the definition of nvme_user_io

The read and write commands don't define a 'result', so there's no need
to copy it back to userspace.

Remove the ability of the ioctl to submit commands to a different
namespace; it's just asking for trouble, and the use case I have in mind
will be addressed througha  different ioctl in the future.  That removes
the need for both the block_shift and nsid arguments.

Check that the opcode is one of 'read' or 'write'.  Future opcodes may
be added in the future, but we will need a different structure definition
for them.

The nblocks field is redefined to be 0-based.  This allows the user to
request the full 65536 blocks.

Don't byteswap the reftag, apptag and appmask.  Martin Petersen tells
me these are calculated in big-endian and are transmitted to the device
in big-endian.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index fd10d597cca7..347ad5f9a721 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -373,17 +373,15 @@ struct nvme_user_io {
         __u8    opcode;
         __u8    flags;
         __u16   control;
-        __u32   nsid;
+        __u16   nblocks;
+        __u16   rsvd;
         __u64   metadata;
         __u64   addr;
         __u64   slba;
-        __u16   nblocks;
-        __u16   block_shift;
         __u32   dsmgmt;
         __u32   reftag;
         __u16   apptag;
         __u16   appmask;
-        __u32   result;
 };
 
 struct nvme_dlfw {
@@ -395,7 +393,7 @@ struct nvme_dlfw {
 #define NVME_IOCTL_IDENTIFY_NS  _IOW('N', 0x40, struct nvme_id_ns)
 #define NVME_IOCTL_IDENTIFY_CTRL _IOW('N', 0x41, struct nvme_id_ctrl)
 #define NVME_IOCTL_GET_RANGE_TYPE _IOW('N', 0x42, struct nvme_lba_range_type)
-#define NVME_IOCTL_SUBMIT_IO    _IOWR('N', 0x43, struct nvme_user_io)
+#define NVME_IOCTL_SUBMIT_IO    _IOW('N', 0x43, struct nvme_user_io)
 #define NVME_IOCTL_DOWNLOAD_FW  _IOW('N', 0x44, struct nvme_dlfw)
 #define NVME_IOCTL_ACTIVATE_FW  _IO('N', 0x45)