5:09 p.m.
Vaibhav Jain <vaibhav(a)linux.ibm.com> writes:
....
+
+/* Papr-scm-header + payload expected with ND_CMD_CALL ioctl from
libnvdimm */
+struct nd_pdsm_cmd_pkg {
+ struct nd_cmd_pkg hdr; /* Package header containing sub-cmd */
+ __s32 cmd_status; /* Out: Sub-cmd status returned back */
+ __u16 payload_offset; /* In: offset from start of struct */
+ __u16 payload_version; /* In/Out: version of the payload */
+ __u8 payload[]; /* In/Out: Sub-cmd data buffer */
+} __packed;
that payload_offset can be avoided if we prevent userspace to user a
different variant of nd_pdsm_cmd_pkg which different header. We can keep
things simpler if we can always find payload at
nd_pdsm_cmd_pkg->payload.
+
+/*
+ * Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
+ * via 'nd_pdsm_cmd_pkg.hdr.nd_command' member of the ioctl struct
+ */
+enum papr_scm_pdsm {
+ PAPR_SCM_PDSM_MIN = 0x0,
+ PAPR_SCM_PDSM_MAX,
+};
+
+/* Convert a libnvdimm nd_cmd_pkg to pdsm specific pkg */
+static inline struct nd_pdsm_cmd_pkg *nd_to_pdsm_cmd_pkg(struct nd_cmd_pkg *cmd)
+{
+ return (struct nd_pdsm_cmd_pkg *) cmd;
+}
+
+/* Return the payload pointer for a given pcmd */
+static inline void *pdsm_cmd_to_payload(struct nd_pdsm_cmd_pkg *pcmd)
+{
+ if (pcmd->hdr.nd_size_in == 0 && pcmd->hdr.nd_size_out == 0)
+ return NULL;
+ else
+ return (void *)((__u8 *) pcmd + pcmd->payload_offset);
+}
+
we need to make sure userspace is not passing a wrong payload_offset.
and in the next patch you do
+ /* Copy the health struct to the payload */
+ memcpy(pdsm_cmd_to_payload(pkg), &p->health, copysize);
+ pkg->hdr.nd_fw_size = copysize;
+
All this can be simplified if you can keep payload at
nd_pdsm_cmd_pkg->payload.
If you still want to have the ability to extend the header, then added a
reserved field similar to nd_cmd_pkg.
-aneesh