cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

ceph_frag.h (2015B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef FS_CEPH_FRAG_H
      3#define FS_CEPH_FRAG_H
      4
      5/*
      6 * "Frags" are a way to describe a subset of a 32-bit number space,
      7 * using a mask and a value to match against that mask.  Any given frag
      8 * (subset of the number space) can be partitioned into 2^n sub-frags.
      9 *
     10 * Frags are encoded into a 32-bit word:
     11 *   8 upper bits = "bits"
     12 *  24 lower bits = "value"
     13 * (We could go to 5+27 bits, but who cares.)
     14 *
     15 * We use the _most_ significant bits of the 24 bit value.  This makes
     16 * values logically sort.
     17 *
     18 * Unfortunately, because the "bits" field is still in the high bits, we
     19 * can't sort encoded frags numerically.  However, it does allow you
     20 * to feed encoded frags as values into frag_contains_value.
     21 */
     22static inline __u32 ceph_frag_make(__u32 b, __u32 v)
     23{
     24	return (b << 24) |
     25		(v & (0xffffffu << (24-b)) & 0xffffffu);
     26}
     27static inline __u32 ceph_frag_bits(__u32 f)
     28{
     29	return f >> 24;
     30}
     31static inline __u32 ceph_frag_value(__u32 f)
     32{
     33	return f & 0xffffffu;
     34}
     35static inline __u32 ceph_frag_mask(__u32 f)
     36{
     37	return (0xffffffu << (24-ceph_frag_bits(f))) & 0xffffffu;
     38}
     39static inline __u32 ceph_frag_mask_shift(__u32 f)
     40{
     41	return 24 - ceph_frag_bits(f);
     42}
     43
     44static inline bool ceph_frag_contains_value(__u32 f, __u32 v)
     45{
     46	return (v & ceph_frag_mask(f)) == ceph_frag_value(f);
     47}
     48
     49static inline __u32 ceph_frag_make_child(__u32 f, int by, int i)
     50{
     51	int newbits = ceph_frag_bits(f) + by;
     52	return ceph_frag_make(newbits,
     53			 ceph_frag_value(f) | (i << (24 - newbits)));
     54}
     55static inline bool ceph_frag_is_leftmost(__u32 f)
     56{
     57	return ceph_frag_value(f) == 0;
     58}
     59static inline bool ceph_frag_is_rightmost(__u32 f)
     60{
     61	return ceph_frag_value(f) == ceph_frag_mask(f);
     62}
     63static inline __u32 ceph_frag_next(__u32 f)
     64{
     65	return ceph_frag_make(ceph_frag_bits(f),
     66			 ceph_frag_value(f) + (0x1000000 >> ceph_frag_bits(f)));
     67}
     68
     69/*
     70 * comparator to sort frags logically, as when traversing the
     71 * number space in ascending order...
     72 */
     73int ceph_frag_compare(__u32 a, __u32 b);
     74
     75#endif