cxl/mbox: Make handle_mailbox_cmd_from_user() use a mbox param

Previously, handle_mailbox_cmd_from_user(), constructed the mailbox
command and dispatched it to the hardware. The construction work
has moved to the validation path.

handle_mailbox_cmd_from_user() now expects a fully validated
mbox param. Make it's caller, cxl_send_cmd(), deliver it. Update
the comments and dereferencing of the new mbox parameter.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/77050ba512d6c30eccf7505467509e460dd325a0.1648687552.git.alison.schofield@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 8c59c69..b4bef3c 100644 (file)
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -423,8 +423,7 @@ int cxl_query_cmd(struct cxl_memdev *cxlmd,
 /**
  * handle_mailbox_cmd_from_user() - Dispatch a mailbox command for userspace.
  * @cxlds: The device data for the operation
- * @cmd: The validated command.
- * @in_payload: Pointer to userspace's input payload.
+ * @mbox_cmd: The validated mailbox command.
  * @out_payload: Pointer to userspace's output payload.
  * @size_out: (Input) Max payload size to copy out.
  *            (Output) Payload size hardware generated.
@@ -439,35 +438,27 @@ int cxl_query_cmd(struct cxl_memdev *cxlmd,
  *  * %-EINTR  - Mailbox acquisition interrupted.
  *  * %-EXXX   - Transaction level failures.
  *
- * Creates the appropriate mailbox command and dispatches it on behalf of a
- * userspace request. The input and output payloads are copied between
- * userspace.
+ * Dispatches a mailbox command on behalf of a userspace request.
+ * The output payload is copied to userspace.
  *
  * See cxl_send_cmd().
  */
 static int handle_mailbox_cmd_from_user(struct cxl_dev_state *cxlds,
-                                       const struct cxl_mem_command *cmd,
-                                       u64 in_payload, u64 out_payload,
-                                       s32 *size_out, u32 *retval)
+                                       struct cxl_mbox_cmd *mbox_cmd,
+                                       u64 out_payload, s32 *size_out,
+                                       u32 *retval)
 {
        struct device *dev = cxlds->dev;
-       struct cxl_mbox_cmd mbox_cmd;
        int rc;
 
-       rc = cxl_mbox_cmd_ctor(&mbox_cmd, cxlds, cmd->opcode,
-                              cmd->info.size_in, cmd->info.size_out,
-                              in_payload);
-       if (rc)
-               return rc;
-
        dev_dbg(dev,
                "Submitting %s command for user\n"
                "\topcode: %x\n"
                "\tsize: %zx\n",
-               cxl_mem_opcode_to_name(mbox_cmd.opcode),
-               mbox_cmd.opcode, mbox_cmd.size_in);
+               cxl_mem_opcode_to_name(mbox_cmd->opcode),
+               mbox_cmd->opcode, mbox_cmd->size_in);
 
-       rc = cxlds->mbox_send(cxlds, &mbox_cmd);
+       rc = cxlds->mbox_send(cxlds, mbox_cmd);
        if (rc)
                goto out;
 
@@ -476,21 +467,21 @@ static int handle_mailbox_cmd_from_user(struct cxl_dev_state *cxlds,
         * to userspace. While the payload may have written more output than
         * this it will have to be ignored.
         */
-       if (mbox_cmd.size_out) {
-               dev_WARN_ONCE(dev, mbox_cmd.size_out > *size_out,
+       if (mbox_cmd->size_out) {
+               dev_WARN_ONCE(dev, mbox_cmd->size_out > *size_out,
                              "Invalid return size\n");
                if (copy_to_user(u64_to_user_ptr(out_payload),
-                                mbox_cmd.payload_out, mbox_cmd.size_out)) {
+                                mbox_cmd->payload_out, mbox_cmd->size_out)) {
                        rc = -EFAULT;
                        goto out;
                }
        }
 
-       *size_out = mbox_cmd.size_out;
-       *retval = mbox_cmd.return_code;
+       *size_out = mbox_cmd->size_out;
+       *retval = mbox_cmd->return_code;
 
 out:
-       cxl_mbox_cmd_dtor(&mbox_cmd);
+       cxl_mbox_cmd_dtor(mbox_cmd);
        return rc;
 }
 
@@ -512,9 +503,8 @@ int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
        if (rc)
                return rc;
 
-       rc = handle_mailbox_cmd_from_user(cxlds, &c, send.in.payload,
-                                         send.out.payload, &send.out.size,
-                                         &send.retval);
+       rc = handle_mailbox_cmd_from_user(cxlds, &mbox_cmd, send.out.payload,
+                                         &send.out.size, &send.retval);
        if (rc)
                return rc;