xfs: use %px for data pointers when debugging

Starting with commit 57e734423a ("vsprintf: refactor %pK code out of
pointer"), the behavior of the raw '%p' printk format specifier was
changed to print a 32-bit hash of the pointer value to avoid leaking
kernel pointers into dmesg.  For most situations that's good.

This is /undesirable/ behavior when we're trying to debug XFS, however,
so define a PTR_FMT that prints the actual pointer when we're in debug
mode.

Note that %p for tracepoints still prints the raw pointer, so in the
long run we could consider rewriting some of these messages as
tracepoints.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_log.c

@@ -2244,7 +2244,7 @@ xlog_write_setup_ophdr(
 		break;
 	default:
 		xfs_warn(log->l_mp,
-			"Bad XFS transaction clientid 0x%x in ticket %p",
+			"Bad XFS transaction clientid 0x%x in ticket "PTR_FMT,
 			ophdr->oh_clientid, ticket);
 		return NULL;
 	}
@@ -3926,7 +3926,7 @@ xlog_verify_iclog(
 		}
 		if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
 			xfs_warn(log->l_mp,
-				"%s: invalid clientid %d op %p offset 0x%lx",
+				"%s: invalid clientid %d op "PTR_FMT" offset 0x%lx",
 				__func__, clientid, ophead,
 				(unsigned long)field_offset);