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/*
* linux/fs/ufs/ufs_swab.c
*
* Copyright (C) 1997
* Francois-Rene Rideau <rideau@ens.fr>
*
*/
/*
* For inspiration, you might wanna check sys/ufs/ffs/fs.h from whateverBSD
*
* NOTES
* 19970406 - Fare <rideau@ens.fr>
* 1) I began from old very preliminary 2.0.x sources,
* but it was underfeatured;
* I later saw that 2.1.1 sources had a *global* UFS byteswap flag.
* EVIL: imagine that a swabbed partition be mounted
* while a non-swabbed partition are active (that sucks!)
* I merged that source tree with mine.
* 2) I hope no one is using obNNUUXXIIous byteorder.
* That's the only thing I might have broken,
* though I rather think it's a fix:
* instead of __u64 like BSD,
* the former driver used an explicitly bigendian array of __u32!
* 3) I provide a few macros that use GCC C Extensions.
* Port to other compilers would require avoiding them.
* in any case, 64 bit (long long) support is required,
* unless you're ready to workaround
* 4) the swab routines below depend on the precise name and order
* of the structure elements. Watch out any modification in ufs_fs.h!!!
* 5) putting byteswapping stuff in ufs_swab* seems cleaner to me.
* 6) These sources should work with both 2.0 and 2.1 kernels...
*
* 19971013 - Fare <rideaufr@issy.cnet.fr>
* 1) Ported to 2.1.57
* 2) instead of byteswapping, use [bl]e_to_cpu:
* it might be that we run on a VAX!
*
* HOWTO continue adding swab support:
* basically, anywhere metadata is bread() (i.e. mapped to block device),
* data should either be SWAB()ed on the fly,
* or copied to a buffer and globally bswap_ufs_*() there.
*
*/
#include <linux/fs.h>
#include "ufs_swab.h"
static __inline__ void n_be16_to_cpus(__u16*p,unsigned n) {
#ifndef __BIG_ENDIAN
unsigned i;
for(i=0;i<n;i++) {
be16_to_cpus(&p[i]);
}
#endif
}
static __inline__ void n_be32_to_cpus(__u32*p,unsigned n) {
#ifndef __BIG_ENDIAN
unsigned i;
for(i=0;i<n;i++) {
be32_to_cpus(&p[i]);
}
#endif
}
static __inline__ void n_le16_to_cpus(__u16*p,unsigned n) {
#ifndef __LITTLE_ENDIAN
unsigned i;
for(i=0;i<n;i++) {
le16_to_cpus(&p[i]);
}
#endif
}
static __inline__ void n_le32_to_cpus(__u32*p,unsigned n) {
#ifndef __LITTLE_ENDIAN
unsigned i;
for(i=0;i<n;i++) {
le32_to_cpus(&p[i]);
}
#endif
}
#define __length_before(p,member) \
((unsigned)(((char*)&((p)->member))-(char*)(p)))
#define __length_since(p,member) \
((unsigned)(sizeof(*p)-__length_before(p,member)))
#define __length_between(p,begin,after_end) \
((unsigned)(__length_before(p,after_end)-__length_before(p,begin)))
#define be32_to_cpus__between(s,begin,after_end) \
n_be32_to_cpus((__u32*)&((s).begin), \
__length_between(&s,begin,after_end)/4)
#define le32_to_cpus__between(s,begin,after_end) \
n_le32_to_cpus((__u32*)&((s).begin), \
__length_between(&s,begin,after_end)/4)
#define be32_to_cpus__since(s,begin) \
n_be32_to_cpus((__u32*)&((s).begin), \
__length_since(&s,begin)/4)
#define le32_to_cpus__since(s,begin) \
n_le32_to_cpus((__u32*)&((s).begin), \
__length_since(&s,begin)/4)
#define be16_to_cpus__between(s,begin,after_end) \
n_be16_to_cpus((__u16*)&((s).begin), \
__length_between(&s,begin,after_end)/2)
#define le16_to_cpus__between(s,begin,after_end) \
n_le16_to_cpus((__u16*)&((s).begin), \
__length_between(&s,begin,after_end)/2)
/*
* Here are the whole-structure swabping routines...
*/
extern void ufs_superblock_be_to_cpus(struct ufs_superblock * usb) {
#ifndef __BIG_ENDIAN
be32_to_cpus__between(*usb,fs_link,fs_fmod);
/* XXX - I dunno what to do w/ fs_csp,
* but it is unused by the current code, so that's ok for now.
*/
be32_to_cpus(&usb->fs_cpc);
be16_to_cpus__between(*usb,fs_opostbl,fs_sparecon);
be32_to_cpus__between(*usb,fs_sparecon,fs_qbmask);
be64_to_cpus(&usb->fs_qbmask);
be64_to_cpus(&usb->fs_qfmask);
be32_to_cpus__between(*usb,fs_postblformat,fs_magic);
#endif
}
extern void ufs_superblock_le_to_cpus(struct ufs_superblock * usb) {
#ifndef __LITTLE_ENDIAN
le32_to_cpus__between(*usb,fs_link,fs_fmod);
/* XXX - I dunno what to do w/ fs_csp,
* but it is unused by the current code, so that's ok for now.
*/
le32_to_cpus(&usb->fs_cpc);
le16_to_cpus__between(*usb,fs_opostbl,fs_sparecon);
le32_to_cpus__between(*usb,fs_sparecon,fs_qbmask);
le64_to_cpus(&usb->fs_qbmask);
le64_to_cpus(&usb->fs_qfmask);
le32_to_cpus__between(*usb,fs_postblformat,fs_magic);
#endif
}
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