slab: use print_hex_dump

Less code and the advantage of ascii dump.

before:
| Slab corruption: names_cache start=c5788000, len=4096
| 000: 6b 6b 01 00 00 00 56 00 00 00 24 00 00 00 2a 00
| 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
| 020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ff
| 030: ff ff ff ff e2 b4 17 18 c7 e4 08 06 00 01 08 00
| 040: 06 04 00 01 e2 b4 17 18 c7 e4 0a 00 00 01 00 00
| 050: 00 00 00 00 0a 00 00 02 6b 6b 6b 6b 6b 6b 6b 6b

after:
| Slab corruption: size-4096 start=c38a9000, len=4096
| 000: 6b 6b 01 00 00 00 56 00 00 00 24 00 00 00 2a 00  kk....V...$...*.
| 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
| 020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ff  ................
| 030: ff ff ff ff d2 56 5f aa db 9c 08 06 00 01 08 00  .....V_.........
| 040: 06 04 00 01 d2 56 5f aa db 9c 0a 00 00 01 00 00  .....V_.........
| 050: 00 00 00 00 0a 00 00 02 6b 6b 6b 6b 6b 6b 6b 6b  ........kkkkkkkk

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

mm/slab.c

@@ -1811,15 +1811,15 @@ static void dump_line(char *data, int offset, int limit)
 	unsigned char error = 0;
 	int bad_count = 0;
 
-	printk(KERN_ERR "%03x:", offset);
+	printk(KERN_ERR "%03x: ", offset);
 	for (i = 0; i < limit; i++) {
 		if (data[offset + i] != POISON_FREE) {
 			error = data[offset + i];
 			bad_count++;
 		}
-		printk(" %02x", (unsigned char)data[offset + i]);
 	}
-	printk("\n");
+	print_hex_dump(KERN_CONT, "", 0, 16, 1,
+			&data[offset], limit, 1);
 
 	if (bad_count == 1) {
 		error ^= POISON_FREE;
@@ -2989,14 +2989,9 @@ bad:
 		printk(KERN_ERR "slab: Internal list corruption detected in "
 				"cache '%s'(%d), slabp %p(%d). Hexdump:\n",
 			cachep->name, cachep->num, slabp, slabp->inuse);
-		for (i = 0;
-		     i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
-		     i++) {
-			if (i % 16 == 0)
-				printk("\n%03x:", i);
-			printk(" %02x", ((unsigned char *)slabp)[i]);
-		}
-		printk("\n");
+		print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp,
+			sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t),
+			1);
 		BUG();
 	}
 }