[PATCH v3 3/9] cxl/mbox: Move build of user mailbox cmd to a helper function

[alison.schofield@intel.com]

From: Alison Schofield <alison.schofield@intel.com>

In preparation for moving the construction of a mailbox command
to the validation path, extract the work into a helper function.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 drivers/cxl/core/mbox.c | 60 +++++++++++++++++++++++++----------------
 1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 28131c6f7fcf..d4233cfb2f99 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -207,6 +207,38 @@ static bool cxl_mem_raw_command_allowed(u16 opcode)
 	return true;
 }
 
+static int cxl_to_mbox_cmd(struct cxl_dev_state *cxlds,
+			   struct cxl_mbox_cmd *mbox, u16 opcode,
+			   size_t in_size, size_t out_size, u64 in_payload)
+{
+	*mbox = (struct cxl_mbox_cmd) {
+		.opcode = opcode,
+		.size_in = in_size,
+		.size_out = out_size,
+	};
+
+	if (!in_size)
+		goto size_out;
+
+	mbox->payload_in = vmemdup_user(u64_to_user_ptr(in_payload), in_size);
+	if (!mbox->payload_in)
+		return PTR_ERR(mbox->payload_in);
+
+size_out:
+	/* Prepare to handle a full payload for variable sized output */
+	if (out_size < 0)
+		mbox->size_out = cxlds->payload_size;
+
+	if (mbox->size_out) {
+		mbox->payload_out = kvzalloc(mbox->size_out, GFP_KERNEL);
+		if (!mbox->payload_out) {
+			kvfree(mbox->payload_in);
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
 static int cxl_to_mem_cmd_raw(struct cxl_dev_state *cxlds,
 			      const struct cxl_send_command *send_cmd,
 			      struct cxl_mem_command *mem_cmd)
@@ -397,27 +429,13 @@ static int handle_mailbox_cmd_from_user(struct cxl_dev_state *cxlds,
 					s32 *size_out, u32 *retval)
 {
 	struct device *dev = cxlds->dev;
-	struct cxl_mbox_cmd mbox_cmd = {
-		.opcode = cmd->opcode,
-		.size_in = cmd->info.size_in,
-		.size_out = cmd->info.size_out,
-	};
+	struct cxl_mbox_cmd mbox_cmd;
 	int rc;
 
-	if (cmd->info.size_out) {
-		mbox_cmd.payload_out = kvzalloc(cmd->info.size_out, GFP_KERNEL);
-		if (!mbox_cmd.payload_out)
-			return -ENOMEM;
-	}
-
-	if (cmd->info.size_in) {
-		mbox_cmd.payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
-						   cmd->info.size_in);
-		if (IS_ERR(mbox_cmd.payload_in)) {
-			kvfree(mbox_cmd.payload_out);
-			return PTR_ERR(mbox_cmd.payload_in);
-		}
-	}
+	rc = cxl_to_mbox_cmd(cxlds, &mbox_cmd, 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"
@@ -471,10 +489,6 @@ int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
 	if (rc)
 		return rc;
 
-	/* Prepare to handle a full payload for variable sized output */
-	if (c.info.size_out < 0)
-		c.info.size_out = cxlds->payload_size;
-
 	rc = handle_mailbox_cmd_from_user(cxlds, &c, send.in.payload,
 					  send.out.payload, &send.out.size,
 					  &send.retval);
-- 
2.31.1