diff options
| -rw-r--r-- | include/linux/bitmap.h | 6 | ||||
| -rw-r--r-- | include/linux/cpumask.h | 22 | ||||
| -rw-r--r-- | include/linux/nodemask.h | 22 | ||||
| -rw-r--r-- | lib/bitmap.c | 158 |
4 files changed, 206 insertions, 2 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 1dbe074..43b406d 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -46,6 +46,8 @@ * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n * bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src) * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit) + * bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap + * bitmap_fold(dst, orig, sz, nbits) dst bits = orig bits mod sz * bitmap_scnprintf(buf, len, src, nbits) Print bitmap src to buf * bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf * bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf @@ -121,6 +123,10 @@ extern void bitmap_remap(unsigned long *dst, const unsigned long *src, const unsigned long *old, const unsigned long *new, int bits); extern int bitmap_bitremap(int oldbit, const unsigned long *old, const unsigned long *new, int bits); +extern void bitmap_onto(unsigned long *dst, const unsigned long *orig, + const unsigned long *relmap, int bits); +extern void bitmap_fold(unsigned long *dst, const unsigned long *orig, + int sz, int bits); extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order); extern void bitmap_release_region(unsigned long *bitmap, int pos, int order); extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order); diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 259c805..9650806 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -14,6 +14,8 @@ * bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c. * For details of cpu_remap(), see bitmap_bitremap in lib/bitmap.c * For details of cpus_remap(), see bitmap_remap in lib/bitmap.c. + * For details of cpus_onto(), see bitmap_onto in lib/bitmap.c. + * For details of cpus_fold(), see bitmap_fold in lib/bitmap.c. * * The available cpumask operations are: * @@ -53,7 +55,9 @@ * int cpulist_scnprintf(buf, len, mask) Format cpumask as list for printing * int cpulist_parse(buf, map) Parse ascii string as cpulist * int cpu_remap(oldbit, old, new) newbit = map(old, new)(oldbit) - * int cpus_remap(dst, src, old, new) *dst = map(old, new)(src) + * void cpus_remap(dst, src, old, new) *dst = map(old, new)(src) + * void cpus_onto(dst, orig, relmap) *dst = orig relative to relmap + * void cpus_fold(dst, orig, sz) dst bits = orig bits mod sz * * for_each_cpu_mask(cpu, mask) for-loop cpu over mask * @@ -330,6 +334,22 @@ static inline void __cpus_remap(cpumask_t *dstp, const cpumask_t *srcp, bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits); } +#define cpus_onto(dst, orig, relmap) \ + __cpus_onto(&(dst), &(orig), &(relmap), NR_CPUS) +static inline void __cpus_onto(cpumask_t *dstp, const cpumask_t *origp, + const cpumask_t *relmapp, int nbits) +{ + bitmap_onto(dstp->bits, origp->bits, relmapp->bits, nbits); +} + +#define cpus_fold(dst, orig, sz) \ + __cpus_fold(&(dst), &(orig), sz, NR_CPUS) +static inline void __cpus_fold(cpumask_t *dstp, const cpumask_t *origp, + int sz, int nbits) +{ + bitmap_fold(dstp->bits, origp->bits, sz, nbits); +} + #if NR_CPUS > 1 #define for_each_cpu_mask(cpu, mask) \ for ((cpu) = first_cpu(mask); \ diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index 905e18f..848025c 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -14,6 +14,8 @@ * bitmap_scnlistprintf() and bitmap_parselist(), also in bitmap.c. * For details of node_remap(), see bitmap_bitremap in lib/bitmap.c. * For details of nodes_remap(), see bitmap_remap in lib/bitmap.c. + * For details of nodes_onto(), see bitmap_onto in lib/bitmap.c. + * For details of nodes_fold(), see bitmap_fold in lib/bitmap.c. * * The available nodemask operations are: * @@ -55,7 +57,9 @@ * int nodelist_scnprintf(buf, len, mask) Format nodemask as list for printing * int nodelist_parse(buf, map) Parse ascii string as nodelist * int node_remap(oldbit, old, new) newbit = map(old, new)(oldbit) - * int nodes_remap(dst, src, old, new) *dst = map(old, new)(dst) + * void nodes_remap(dst, src, old, new) *dst = map(old, new)(src) + * void nodes_onto(dst, orig, relmap) *dst = orig relative to relmap + * void nodes_fold(dst, orig, sz) dst bits = orig bits mod sz * * for_each_node_mask(node, mask) for-loop node over mask * @@ -326,6 +330,22 @@ static inline void __nodes_remap(nodemask_t *dstp, const nodemask_t *srcp, bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits); } +#define nodes_onto(dst, orig, relmap) \ + __nodes_onto(&(dst), &(orig), &(relmap), MAX_NUMNODES) +static inline void __nodes_onto(nodemask_t *dstp, const nodemask_t *origp, + const nodemask_t *relmapp, int nbits) +{ + bitmap_onto(dstp->bits, origp->bits, relmapp->bits, nbits); +} + +#define nodes_fold(dst, orig, sz) \ + __nodes_fold(&(dst), &(orig), sz, MAX_NUMNODES) +static inline void __nodes_fold(nodemask_t *dstp, const nodemask_t *origp, + int sz, int nbits) +{ + bitmap_fold(dstp->bits, origp->bits, sz, nbits); +} + #if MAX_NUMNODES > 1 #define for_each_node_mask(node, mask) \ for ((node) = first_node(mask); \ diff --git a/lib/bitmap.c b/lib/bitmap.c index a6939e1..c4cb48f 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -714,6 +714,164 @@ int bitmap_bitremap(int oldbit, const unsigned long *old, } EXPORT_SYMBOL(bitmap_bitremap); +/** + * bitmap_onto - translate one bitmap relative to another + * @dst: resulting translated bitmap + * @orig: original untranslated bitmap + * @relmap: bitmap relative to which translated + * @bits: number of bits in each of these bitmaps + * + * Set the n-th bit of @dst iff there exists some m such that the + * n-th bit of @relmap is set, the m-th bit of @orig is set, and + * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. + * (If you understood the previous sentence the first time your + * read it, you're overqualified for your current job.) + * + * In other words, @orig is mapped onto (surjectively) @dst, + * using the the map { <n, m> | the n-th bit of @relmap is the + * m-th set bit of @relmap }. + * + * Any set bits in @orig above bit number W, where W is the + * weight of (number of set bits in) @relmap are mapped nowhere. + * In particular, if for all bits m set in @orig, m >= W, then + * @dst will end up empty. In situations where the possibility + * of such an empty result is not desired, one way to avoid it is + * to use the bitmap_fold() operator, below, to first fold the + * @orig bitmap over itself so that all its set bits x are in the + * range 0 <= x < W. The bitmap_fold() operator does this by + * setting the bit (m % W) in @dst, for each bit (m) set in @orig. + * + * Example [1] for bitmap_onto(): + * Let's say @relmap has bits 30-39 set, and @orig has bits + * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, + * @dst will have bits 31, 33, 35, 37 and 39 set. + * + * When bit 0 is set in @orig, it means turn on the bit in + * @dst corresponding to whatever is the first bit (if any) + * that is turned on in @relmap. Since bit 0 was off in the + * above example, we leave off that bit (bit 30) in @dst. + * + * When bit 1 is set in @orig (as in the above example), it + * means turn on the bit in @dst corresponding to whatever + * is the second bit that is turned on in @relmap. The second + * bit in @relmap that was turned on in the above example was + * bit 31, so we turned on bit 31 in @dst. + * + * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, + * because they were the 4th, 6th, 8th and 10th set bits + * set in @relmap, and the 4th, 6th, 8th and 10th bits of + * @orig (i.e. bits 3, 5, 7 and 9) were also set. + * + * When bit 11 is set in @orig, it means turn on the bit in + * @dst corresponding to whatever is the twelth bit that is + * turned on in @relmap. In the above example, there were + * only ten bits turned on in @relmap (30..39), so that bit + * 11 was set in @orig had no affect on @dst. + * + * Example [2] for bitmap_fold() + bitmap_onto(): + * Let's say @relmap has these ten bits set: + * 40 41 42 43 45 48 53 61 74 95 + * (for the curious, that's 40 plus the first ten terms of the + * Fibonacci sequence.) + * + * Further lets say we use the following code, invoking + * bitmap_fold() then bitmap_onto, as suggested above to + * avoid the possitility of an empty @dst result: + * + * unsigned long *tmp; // a temporary bitmap's bits + * + * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); + * bitmap_onto(dst, tmp, relmap, bits); + * + * Then this table shows what various values of @dst would be, for + * various @orig's. I list the zero-based positions of each set bit. + * The tmp column shows the intermediate result, as computed by + * using bitmap_fold() to fold the @orig bitmap modulo ten + * (the weight of @relmap). + * + * @orig tmp @dst + * 0 0 40 + * 1 1 41 + * 9 9 95 + * 10 0 40 (*) + * 1 3 5 7 1 3 5 7 41 43 48 61 + * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 + * 0 9 18 27 0 9 8 7 40 61 74 95 + * 0 10 20 30 0 40 + * 0 11 22 33 0 1 2 3 40 41 42 43 + * 0 12 24 36 0 2 4 6 40 42 45 53 + * 78 102 211 1 2 8 41 42 74 (*) + * + * (*) For these marked lines, if we hadn't first done bitmap_fold() + * into tmp, then the @dst result would have been empty. + * + * If either of @orig or @relmap is empty (no set bits), then @dst + * will be returned empty. + * + * If (as explained above) the only set bits in @orig are in positions + * m where m >= W, (where W is the weight of @relmap) then @dst will + * once again be returned empty. + * + * All bits in @dst not set by the above rule are cleared. + */ +void bitmap_onto(unsigned long *dst, const unsigned long *orig, + const unsigned long *relmap, int bits) +{ + int n, m; /* same meaning as in above comment */ + + if (dst == orig) /* following doesn't handle inplace mappings */ + return; + bitmap_zero(dst, bits); + + /* + * The following code is a more efficient, but less + * obvious, equivalent to the loop: + * for (m = 0; m < bitmap_weight(relmap, bits); m++) { + * n = bitmap_ord_to_pos(orig, m, bits); + * if (test_bit(m, orig)) + * set_bit(n, dst); + * } + */ + + m = 0; + for (n = find_first_bit(relmap, bits); + n < bits; + n = find_next_bit(relmap, bits, n + 1)) { + /* m == bitmap_pos_to_ord(relmap, n, bits) */ + if (test_bit(m, orig)) + set_bit(n, dst); + m++; + } +} +EXPORT_SYMBOL(bitmap_onto); + +/** + * bitmap_fold - fold larger bitmap into smaller, modulo specified size + * @dst: resulting smaller bitmap + * @orig: original larger bitmap + * @sz: specified size + * @bits: number of bits in each of these bitmaps + * + * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. + * Clear all other bits in @dst. See further the comment and + * Example [2] for bitmap_onto() for why and how to use this. + */ +void bitmap_fold(unsigned long *dst, const unsigned long *orig, + int sz, int bits) +{ + int oldbit; + + if (dst == orig) /* following doesn't handle inplace mappings */ + return; + bitmap_zero(dst, bits); + + for (oldbit = find_first_bit(orig, bits); + oldbit < bits; + oldbit = find_next_bit(orig, bits, oldbit + 1)) + set_bit(oldbit % sz, dst); +} +EXPORT_SYMBOL(bitmap_fold); + /* * Common code for bitmap_*_region() routines. * bitmap: array of unsigned longs corresponding to the bitmap |
