[PARTITION] MSDOS: Fix Sun num_partitions handling.

Correct the Solaris x86 number of partitions (slices) is a way that is
backward compatible with the earlier size.

This works without a new VTOC structure definition as the timestamp
and v_asciilabel fields in the VTOC are not used by the kernel yet.
Signed-off-by: Mark Fortescue <mark@mtfhpc.demon.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

fs/partitions/msdos.c

@@ -203,6 +203,7 @@ parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev,
 	Sector sect;
 	struct solaris_x86_vtoc *v;
 	int i;
+	short max_nparts;
 
 	v = (struct solaris_x86_vtoc *)read_dev_sector(bdev, offset+1, &sect);
 	if (!v)
@@ -218,7 +219,9 @@ parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev,
 		put_dev_sector(sect);
 		return;
 	}
-	for (i=0; i<SOLARIS_X86_NUMSLICE && state->next<state->limit; i++) {
+	/* Ensure we can handle previous case of VTOC with 8 entries gracefully */
+	max_nparts = le16_to_cpu (v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
+	for (i=0; i<max_nparts && state->next<state->limit; i++) {
 		struct solaris_x86_slice *s = &v->v_slice[i];
 		if (s->s_size == 0)
 			continue;

include/linux/genhd.h

@@ -264,7 +264,7 @@ static inline void set_capacity(struct gendisk *disk, sector_t size)
 
 #ifdef CONFIG_SOLARIS_X86_PARTITION
 
-#define SOLARIS_X86_NUMSLICE	8
+#define SOLARIS_X86_NUMSLICE	16
 #define SOLARIS_X86_VTOC_SANE	(0x600DDEEEUL)
 
 struct solaris_x86_slice {