[PATCH V4] ieee1275/ofdisk: vscsi lun handling on lun len

[Mukesh Kumar Chaurasiya]

The information about "vscsi-report-luns" data is a list of disk details
with pairs of memory addresses and lengths.

                  8 bytes     8 bytes
lun-addr  --->   ------------------------              8 bytes
        ^        |  buf-addr | lun-count| --------> -------------
        |        ------------------------           |   lun     |
        |        |  buf-addr | lun-count| ----|     -------------
     "len"       ------------------------     |     |  ...      |
        |        |    ...               |     |     -------------
        |        ------------------------     |     |   lun     |
        |        |  buf-addr | lun-count|     |     -------------
        V        ------------------------     |
                                              |---> -------------
                                                    |   lun     |
                                                    -------------
                                                    |  ...      |
                                                    -------------
                                                    |   lun     |
                                                    -------------
The way the expression (args.table + 4 + 8 * i) is used is incorrect and
can be confusing. The list of LUNs doesn't end with NULL, indicated by
while (*ptr). Usually, this loop doesn't process any LUNs because it ends
before checking any as first reported LUN is likely to be 0. The list of
LUNs ends based on its length, not by a NULL value.

Signed-off-by: Mukesh Kumar Chaurasiya <mchauras@linux.ibm.com>
---
 grub-core/disk/ieee1275/ofdisk.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/grub-core/disk/ieee1275/ofdisk.c b/grub-core/disk/ieee1275/ofdisk.c
index c6cba0c8a..b446bb1e7 100644
--- a/grub-core/disk/ieee1275/ofdisk.c
+++ b/grub-core/disk/ieee1275/ofdisk.c
@@ -43,6 +43,12 @@ struct ofdisk_hash_ent
   struct ofdisk_hash_ent *next;
 };
 
+struct lun_buf
+{
+  grub_uint64_t buf_addr;
+  grub_uint64_t lun_count;
+};
+
 static grub_err_t
 grub_ofdisk_get_block_size (const char *device, grub_uint32_t *block_size,
                            struct ofdisk_hash_ent *op);
@@ -222,8 +228,9 @@ dev_iterate (const struct grub_ieee1275_devalias *alias)
        grub_ieee1275_cell_t table;
       }
       args;
+      struct lun_buf *tbl;
       char *buf, *bufptr;
-      unsigned i;
+      unsigned int i, j;
 
       if (grub_ieee1275_open (alias->path, &ihandle))
        return;
@@ -248,17 +255,18 @@ dev_iterate (const struct grub_ieee1275_devalias *alias)
        return;
       bufptr = grub_stpcpy (buf, alias->path);
 
+      tbl = (struct lun_len *) args.table;
       for (i = 0; i < args.nentries; i++)
-       {
-         grub_uint64_t *ptr;
-
-         ptr = *(grub_uint64_t **) (args.table + 4 + 8 * i);
-         while (*ptr)
-           {
-             grub_snprintf (bufptr, 32, "/disk@%" PRIxGRUB_UINT64_T, *ptr++);
-             dev_iterate_real (buf, buf);
-           }
-       }
+        {
+          grub_uint64_t *ptr;
+
+          ptr = (grub_uint64_t *)(grub_addr_t) tbl[i].buf_addr;
+          for (j = 0; j < tbl[i].lun_count; j++)
+           {
+             grub_snprintf (bufptr, 32, "/disk@%" PRIxGRUB_UINT64_T, *ptr++);
+             dev_iterate_real (buf, buf);
+           }
+        }
       grub_ieee1275_close (ihandle);
       grub_free (buf);
       return;
-- 
2.47.0