+/**
+ * p9_check_zc_errors - check 9p packet for error return and process it
+ * @c: current client instance
+ * @req: request to parse and check for error conditions
+ * @in_hdrlen: Size of response protocol buffer.
+ *
+ * returns error code if one is discovered, otherwise returns 0
+ *
+ * this will have to be more complicated if we have multiple
+ * error packet types
+ */
+
+static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
+ char *uidata, int in_hdrlen, int kern_buf)
+{
+ int err;
+ int ecode;
+ int8_t type;
+ char *ename = NULL;
+
+ err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
+ if (err) {
+ P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
+ return err;
+ }
+
+ if (type != P9_RERROR && type != P9_RLERROR)
+ return 0;
+
+ if (!p9_is_proto_dotl(c)) {
+ /* Error is reported in string format */
+ uint16_t len;
+ /* 7 = header size for RERROR, 2 is the size of string len; */
+ int inline_len = in_hdrlen - (7 + 2);
+
+ /* Read the size of error string */
+ err = p9pdu_readf(req->rc, c->proto_version, "w", &len);
+ if (err)
+ goto out_err;
+
+ ename = kmalloc(len + 1, GFP_NOFS);
+ if (!ename) {
+ err = -ENOMEM;
+ goto out_err;
+ }
+ if (len <= inline_len) {
+ /* We have error in protocol buffer itself */
+ if (pdu_read(req->rc, ename, len)) {
+ err = -EFAULT;
+ goto out_free;
+
+ }
+ } else {
+ /*
+ * Part of the data is in user space buffer.
+ */
+ if (pdu_read(req->rc, ename, inline_len)) {
+ err = -EFAULT;
+ goto out_free;
+
+ }
+ if (kern_buf) {
+ memcpy(ename + inline_len, uidata,
+ len - inline_len);
+ } else {
+ err = copy_from_user(ename + inline_len,
+ uidata, len - inline_len);
+ if (err) {
+ err = -EFAULT;
+ goto out_free;
+ }
+ }
+ }
+ ename[len] = 0;
+ if (p9_is_proto_dotu(c)) {
+ /* For dotu we also have error code */
+ err = p9pdu_readf(req->rc,
+ c->proto_version, "d", &ecode);
+ if (err)
+ goto out_free;
+ err = -ecode;
+ }
+ if (!err || !IS_ERR_VALUE(err)) {
+ err = p9_errstr2errno(ename, strlen(ename));
+
+ P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
+ -ecode, ename);
+ }
+ kfree(ename);
+ } else {
+ err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
+ err = -ecode;
+
+ P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
+ }
+ return err;
+
+out_free:
+ kfree(ename);
+out_err:
+ P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
+ return err;
+}
+