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>

2 files changed, 20 insertions, 15 deletions

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index d0b52622e261..90a96ec8a596 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -1035,29 +1035,37 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
         struct nvme_user_io io;
         struct nvme_command c;
         unsigned length;
-        u32 result;
         int nents, status;
         struct scatterlist *sg;
         struct nvme_prps *prps;
 
         if (copy_from_user(&io, uio, sizeof(io)))
                 return -EFAULT;
-        length = io.nblocks << io.block_shift;
-        nents = nvme_map_user_pages(dev, io.opcode & 1, io.addr, length, &sg);
+        length = (io.nblocks + 1) << ns->lba_shift;
+
+        switch (io.opcode) {
+        case nvme_cmd_write:
+        case nvme_cmd_read:
+                nents = nvme_map_user_pages(dev, io.opcode & 1, io.addr,
+                                                                length, &sg);
+        default:
+                return -EFAULT;
+        }
+
         if (nents < 0)
                 return nents;
 
         memset(&c, 0, sizeof(c));
         c.rw.opcode = io.opcode;
         c.rw.flags = io.flags;
-        c.rw.nsid = cpu_to_le32(io.nsid);
+        c.rw.nsid = cpu_to_le32(ns->ns_id);
         c.rw.slba = cpu_to_le64(io.slba);
-        c.rw.length = cpu_to_le16(io.nblocks - 1);
+        c.rw.length = cpu_to_le16(io.nblocks);
         c.rw.control = cpu_to_le16(io.control);
         c.rw.dsmgmt = cpu_to_le16(io.dsmgmt);
-        c.rw.reftag = cpu_to_le32(io.reftag);   /* XXX: endian? */
-        c.rw.apptag = cpu_to_le16(io.apptag);
-        c.rw.appmask = cpu_to_le16(io.appmask);
+        c.rw.reftag = io.reftag;
+        c.rw.apptag = io.apptag;
+        c.rw.appmask = io.appmask;
         /* XXX: metadata */
         prps = nvme_setup_prps(dev, &c.common, sg, length);
 
@@ -1069,11 +1077,10 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
          * additional races since q_lock already protects against other CPUs.
          */
         put_nvmeq(nvmeq);
-        status = nvme_submit_sync_cmd(nvmeq, &c, &result, IO_TIMEOUT);
+        status = nvme_submit_sync_cmd(nvmeq, &c, NULL, IO_TIMEOUT);
 
         nvme_unmap_user_pages(dev, io.opcode & 1, io.addr, length, sg, nents);
         nvme_free_prps(dev, prps);
-        put_user(result, &uio->result);
         return status;
 }
 
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)