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lib/find: optimize for_each() macros
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Moving an iterator of the macros inside conditional part of for-loop
helps to generate a better code. It had been first implemented in commit
7baac8b ("cpumask: make for_each_cpu_mask a bit smaller").

Now that cpumask for-loops are the aliases to bitmap loops, it's worth
to optimize them the same way.

Bloat-o-meter says:
add/remove: 8/12 grow/shrink: 147/592 up/down: 4876/-24416 (-19540)

Signed-off-by: Yury Norov <yury.norov@gmail.com>
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Yury Norov committed Sep 27, 2022
1 parent 9d2c24f commit 04af4d2
Showing 1 changed file with 25 additions and 31 deletions.
56 changes: 25 additions & 31 deletions include/linux/find.h
Original file line number Diff line number Diff line change
Expand Up @@ -458,31 +458,25 @@ unsigned long find_next_bit_le(const void *addr, unsigned
#endif

#define for_each_set_bit(bit, addr, size) \
for ((bit) = find_next_bit((addr), (size), 0); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
for ((bit) = 0; (bit) = find_next_bit((addr), (size), (bit)), (bit) < (size); (bit)++)

#define for_each_and_bit(bit, addr1, addr2, size) \
for ((bit) = find_next_and_bit((addr1), (addr2), (size), 0); \
(bit) < (size); \
(bit) = find_next_and_bit((addr1), (addr2), (size), (bit) + 1))
for ((bit) = 0; \
(bit) = find_next_and_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
(bit)++)

/* same as for_each_set_bit() but use bit as value to start with */
#define for_each_set_bit_from(bit, addr, size) \
for ((bit) = find_next_bit((addr), (size), (bit)); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
for (; (bit) = find_next_bit((addr), (size), (bit)), (bit) < (size); (bit)++)

#define for_each_clear_bit(bit, addr, size) \
for ((bit) = find_next_zero_bit((addr), (size), 0); \
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
for ((bit) = 0; \
(bit) = find_next_zero_bit((addr), (size), (bit)), (bit) < (size); \
(bit)++)

/* same as for_each_clear_bit() but use bit as value to start with */
#define for_each_clear_bit_from(bit, addr, size) \
for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
for (; (bit) = find_next_zero_bit((addr), (size), (bit)), (bit) < (size); (bit)++)

/**
* for_each_set_bitrange - iterate over all set bit ranges [b; e)
Expand All @@ -492,11 +486,11 @@ unsigned long find_next_bit_le(const void *addr, unsigned
* @size: bitmap size in number of bits
*/
#define for_each_set_bitrange(b, e, addr, size) \
for ((b) = find_next_bit((addr), (size), 0), \
(e) = find_next_zero_bit((addr), (size), (b) + 1); \
for ((b) = 0; \
(b) = find_next_bit((addr), (size), b), \
(e) = find_next_zero_bit((addr), (size), (b) + 1), \
(b) < (size); \
(b) = find_next_bit((addr), (size), (e) + 1), \
(e) = find_next_zero_bit((addr), (size), (b) + 1))
(b) = (e) + 1)

/**
* for_each_set_bitrange_from - iterate over all set bit ranges [b; e)
Expand All @@ -506,11 +500,11 @@ unsigned long find_next_bit_le(const void *addr, unsigned
* @size: bitmap size in number of bits
*/
#define for_each_set_bitrange_from(b, e, addr, size) \
for ((b) = find_next_bit((addr), (size), (b)), \
(e) = find_next_zero_bit((addr), (size), (b) + 1); \
for (; \
(b) = find_next_bit((addr), (size), (b)), \
(e) = find_next_zero_bit((addr), (size), (b) + 1), \
(b) < (size); \
(b) = find_next_bit((addr), (size), (e) + 1), \
(e) = find_next_zero_bit((addr), (size), (b) + 1))
(b) = (e) + 1)

/**
* for_each_clear_bitrange - iterate over all unset bit ranges [b; e)
Expand All @@ -520,11 +514,11 @@ unsigned long find_next_bit_le(const void *addr, unsigned
* @size: bitmap size in number of bits
*/
#define for_each_clear_bitrange(b, e, addr, size) \
for ((b) = find_next_zero_bit((addr), (size), 0), \
(e) = find_next_bit((addr), (size), (b) + 1); \
for ((b) = 0; \
(b) = find_next_zero_bit((addr), (size), (b)), \
(e) = find_next_bit((addr), (size), (b) + 1), \
(b) < (size); \
(b) = find_next_zero_bit((addr), (size), (e) + 1), \
(e) = find_next_bit((addr), (size), (b) + 1))
(b) = (e) + 1)

/**
* for_each_clear_bitrange_from - iterate over all unset bit ranges [b; e)
Expand All @@ -534,11 +528,11 @@ unsigned long find_next_bit_le(const void *addr, unsigned
* @size: bitmap size in number of bits
*/
#define for_each_clear_bitrange_from(b, e, addr, size) \
for ((b) = find_next_zero_bit((addr), (size), (b)), \
(e) = find_next_bit((addr), (size), (b) + 1); \
for (; \
(b) = find_next_zero_bit((addr), (size), (b)), \
(e) = find_next_bit((addr), (size), (b) + 1), \
(b) < (size); \
(b) = find_next_zero_bit((addr), (size), (e) + 1), \
(e) = find_next_bit((addr), (size), (b) + 1))
(b) = (e) + 1)

/**
* for_each_set_bit_wrap - iterate over all set bits starting from @start, and
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