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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
Message-Id: <20210413143247.546256-1-ben.widawsky@intel.com>
MIME-Version: 1.0
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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