xenstore.c: return error number

[Masato Asou]

Hi,

Return error number instead of call panic().

comment, ok?
--
ASOU Masato

diff --git a/sys/dev/pv/xenstore.c b/sys/dev/pv/xenstore.c
index 1e4f15d30eb..dc89ba0fa6d 100644
--- a/sys/dev/pv/xenstore.c
+++ b/sys/dev/pv/xenstore.c
@@ -118,6 +118,7 @@ struct xs_msg {
        struct xs_msghdr         xsm_hdr;
        uint32_t                 xsm_read;
        uint32_t                 xsm_dlen;
+       int                      xsm_error;
        uint8_t                 *xsm_data;
        TAILQ_ENTRY(xs_msg)      xsm_link;
 };
@@ -566,9 +567,7 @@ xs_intr(void *arg)
        }
 
        if (xsm->xsm_hdr.xmh_len > xsm->xsm_dlen)
-               panic("message too large: %d vs %d for type %d, rid %u",
-                   xsm->xsm_hdr.xmh_len, xsm->xsm_dlen, xsm->xsm_hdr.xmh_type,
-                   xsm->xsm_hdr.xmh_rid);
+               xsm->xsm_error = EMSGSIZE;
 
        len = MIN(xsm->xsm_hdr.xmh_len - xsm->xsm_read, avail);
        if (len) {
@@ -800,7 +799,9 @@ xs_cmd(struct xs_transaction *xst, int cmd, const char 
*path,
                error = xs_geterror(xsm);
                DPRINTF("%s: xenstore request %d \"%s\" error %s\n",
                    xs->xs_sc->sc_dev.dv_xname, cmd, path, xsm->xsm_data);
-       } else if (mode == READ) {
+       } else if (xsm->xsm_error != 0)
+               error = xsm->xsm_error;
+       else if (mode == READ) {
                KASSERT(iov && iov_cnt);
                error = xs_parse(xst, xsm, iov, iov_cnt);
        }