1 /*- 2 * Copyright (c) 2010 Isilon Systems, Inc. 3 * Copyright (c) 2010 iX Systems, Inc. 4 * Copyright (c) 2010 Panasas, Inc. 5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice unmodified, this list of conditions, and the following 13 * disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 #ifndef _LINUXKPI_LINUX_KDEV_T_H_ 30 #define _LINUXKPI_LINUX_KDEV_T_H_ 31 32 #include <sys/types.h> 33 34 /* 35 * The encoding of major/minor on FreeBSD is complex to take into account the 36 * compatibility with 16-bit dev_t (see <sys/types.h>). It is not possible to 37 * use a simple shift and thus, we can't have a proper definition of 38 * `MINORBITS`. 39 * 40 * At the time this is added to linuxkpi, this is used by the DRM generic code 41 * as the upper limit to allocate an ID using an xarray. It is not used to 42 * decode a minor, therefore any arbitrary value here is fine in this context. 43 * 44 * On Linux, the value is set to 20. Because of the above, we reuse this value, 45 * even so it does not correspond to the actual minor encoding on FreeBSD. 46 */ 47 #define MINORBITS 20 48 49 #define MAJOR(dev) major(dev) 50 #define MINOR(dev) minor(dev) 51 #define MKDEV(ma, mi) makedev(ma, mi) 52 53 static inline uint16_t 54 old_encode_dev(dev_t dev) 55 { 56 return ((MAJOR(dev) << 8) | MINOR(dev)); 57 } 58 59 #endif /* _LINUXKPI_LINUX_KDEV_T_H_ */ 60