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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576/* SPDX-License-Identifier: GPL-2.0 */#ifndef FS_CEPH_FRAG_H#define FS_CEPH_FRAG_H
/* * "Frags" are a way to describe a subset of a 32-bit number space, * using a mask and a value to match against that mask. Any given frag * (subset of the number space) can be partitioned into 2^n sub-frags. * * Frags are encoded into a 32-bit word: * 8 upper bits = "bits" * 24 lower bits = "value" * (We could go to 5+27 bits, but who cares.) * * We use the _most_ significant bits of the 24 bit value. This makes * values logically sort. * * Unfortunately, because the "bits" field is still in the high bits, we * can't sort encoded frags numerically. However, it does allow you * to feed encoded frags as values into frag_contains_value. */static inline __u32 ceph_frag_make(__u32 b, __u32 v){ return (b << 24) | (v & (0xffffffu << (24-b)) & 0xffffffu);}static inline __u32 ceph_frag_bits(__u32 f){ return f >> 24;}static inline __u32 ceph_frag_value(__u32 f){ return f & 0xffffffu;}static inline __u32 ceph_frag_mask(__u32 f){ return (0xffffffu << (24-ceph_frag_bits(f))) & 0xffffffu;}static inline __u32 ceph_frag_mask_shift(__u32 f){ return 24 - ceph_frag_bits(f);}
static inline bool ceph_frag_contains_value(__u32 f, __u32 v){ return (v & ceph_frag_mask(f)) == ceph_frag_value(f);}
static inline __u32 ceph_frag_make_child(__u32 f, int by, int i){ int newbits = ceph_frag_bits(f) + by; return ceph_frag_make(newbits, ceph_frag_value(f) | (i << (24 - newbits)));}static inline bool ceph_frag_is_leftmost(__u32 f){ return ceph_frag_value(f) == 0;}static inline bool ceph_frag_is_rightmost(__u32 f){ return ceph_frag_value(f) == ceph_frag_mask(f);}static inline __u32 ceph_frag_next(__u32 f){ return ceph_frag_make(ceph_frag_bits(f), ceph_frag_value(f) + (0x1000000 >> ceph_frag_bits(f)));}
/* * comparator to sort frags logically, as when traversing the * number space in ascending order... */int ceph_frag_compare(__u32 a, __u32 b);
#endif