[PATCH] cxl/mem: Clarify UAPI documentation

From: Ben Widawsky <ben.widawsky@intel.com>
To: linux-cxl@vger.kernel.org
Cc: Ben Widawsky <ben.widawsky@intel.com>,
	linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org,
	ira.weiny@intel.com, vishal.l.verma@intel.com,
	alison.schofield@intel.com, dan.j.williams@intel.com,
	linux-kernel@vger.kernel.org
Subject: [PATCH] cxl/mem: Clarify UAPI documentation
Date: Tue, 13 Apr 2021 07:32:47 -0700	[thread overview]
Message-ID: <20210413143247.546256-1-ben.widawsky@intel.com> (raw)

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
 include/uapi/linux/cxl_mem.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index f6e8a005b113..8dd516ddb098 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -81,6 +81,13 @@ static const struct {
  *  - @size_in = -1
  *  - @size_out = 0
  *
+ * Commands which have a variable length input likely have a minimum length.
+ * This is not enforced by the UAPI, and therefore might look like the command
+ * succeeded when sending too small of an input payload. Caution should be taken
+ * by checking the @cxl_send_command.retval for such cases. For commands with a
+ * variable length output, the caller is free to consume as little or as much as
+ * they want.
+ *
  * See struct cxl_mem_query_commands.
  */
 struct cxl_command_info {
-- 
2.31.1

