[PATCH] Generalize MD_MAX_DISKS to GRUB_MDRAID_MAX_DISKS

[Julian Andres Klode]

Move the constant from getroot.c to disk.h and then reuse
it place of the hardcoded 1024 limit in diskfilter.

Fixes: 2a5e3c1f2 (disk/diskfilter: Don't make a RAID array with more than 1024 
disks)
Cc: Daniel Axtens <dja@axtens.net>
Cc: Kees Cook <keescook@chromium.org>
---
 grub-core/disk/diskfilter.c     |  4 ++--
 grub-core/osdep/linux/getroot.c | 12 ++----------
 include/grub/disk.h             | 10 ++++++++++
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/grub-core/disk/diskfilter.c b/grub-core/disk/diskfilter.c
index 1c568927b..61a311efd 100644
--- a/grub-core/disk/diskfilter.c
+++ b/grub-core/disk/diskfilter.c
@@ -1046,8 +1046,8 @@ grub_diskfilter_make_raid (grub_size_t uuidlen, char 
*uuid, int nmemb,
   struct grub_diskfilter_pv *pv;
   grub_err_t err;
 
-  /* We choose not to support more than 1024 disks. */
-  if (nmemb < 1 || nmemb > 1024)
+  /* We choose not to support more than the specified number of disks. */
+  if (nmemb < 1 || nmemb > GRUB_MDRAID_MAX_DISKS)
     {
       grub_free (uuid);
       return NULL;
diff --git a/grub-core/osdep/linux/getroot.c b/grub-core/osdep/linux/getroot.c
index 9cf037ec2..7dd775d2a 100644
--- a/grub-core/osdep/linux/getroot.c
+++ b/grub-core/osdep/linux/getroot.c
@@ -44,6 +44,7 @@
 
 #include <grub/mm.h>
 #include <grub/misc.h>
+#include <grub/disk.h>
 #include <grub/emu/misc.h>
 #include <grub/emu/hostdisk.h>
 #include <grub/emu/getroot.h>
@@ -130,15 +131,6 @@ struct mountinfo_entry
   char fstype[ESCAPED_PATH_MAX + 1], device[ESCAPED_PATH_MAX + 1];
 };
 
-/*
- * GET_DISK_INFO nr_disks (total count) does not map to disk.number,
- * which is an internal kernel index. Instead, do what mdadm does
- * and keep scanning until we find enough valid disks. The limit is
- * copied from there, which notes that it is sufficiently high given
- * that the on-disk metadata for v1.x can only support 1920.
- */
-#define MD_MAX_DISKS       4096
-
 static char **
 grub_util_raid_getmembers (const char *name, int bootable)
 {
@@ -176,7 +168,7 @@ grub_util_raid_getmembers (const char *name, int bootable)
   devicelist = xcalloc (info.nr_disks + 1, sizeof (char *));
 
   remaining = info.nr_disks;
-  for (i = 0, j = 0; i < MD_MAX_DISKS && remaining > 0; i++)
+  for (i = 0, j = 0; i < GRUB_MDRAID_MAX_DISKS && remaining > 0; i++)
     {
       disk.number = i;
       ret = ioctl (fd, GET_DISK_INFO, &disk);
diff --git a/include/grub/disk.h b/include/grub/disk.h
index 071b2f7df..cbd05e9c7 100644
--- a/include/grub/disk.h
+++ b/include/grub/disk.h
@@ -172,6 +172,16 @@ typedef struct grub_disk_memberlist 
*grub_disk_memberlist_t;
 /* The maximum number of disk caches.  */
 #define GRUB_DISK_CACHE_NUM    1021
 
+/* The maximum number of disks in an mdraid device.
+ *
+ * GET_DISK_INFO nr_disks (total count) does not map to disk.number,
+ * which is an internal kernel index. Instead, do what mdadm does
+ * and keep scanning until we find enough valid disks. The limit is
+ * copied from there, which notes that it is sufficiently high given
+ * that the on-disk metadata for v1.x can only support 1920.
+ */
+#define GRUB_MDRAID_MAX_DISKS  4096
+
 /* The size of a disk cache in 512B units. Must be at least as big as the
    largest supported sector size, currently 16K.  */
 #define GRUB_DISK_CACHE_BITS   6
-- 
2.40.1