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Commit 18c41b37 authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Linus Torvalds
Browse files

nilfs2: refactor nilfs_palloc_find_available_slot() 



The current implementation of nilfs_palloc_find_available_slot() function
is overkill.  The underlying bit search routine is well optimized, so this
uses it more simply in nilfs_palloc_find_available_slot().

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4e9e63a6

fs/nilfs2/alloc.c

+21 −27
Original line number Diff line number Diff line
@@ -335,39 +335,33 @@ void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr, 
 */

static int nilfs_palloc_find_available_slot(unsigned char *bitmap,

					    unsigned long target,

					    int bsize,

					    unsigned bsize,

					    spinlock_t *lock)

{

	int curr, pos, end, i;

	int pos, end = bsize;



	if (target > 0) {

		end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);

		if (end > bsize)

			end = bsize;

		pos = nilfs_find_next_zero_bit(bitmap, end, target);

		if (pos < end && !nilfs_set_bit_atomic(lock, pos, bitmap))

	if (likely(target < bsize)) {

		pos = target;

		do {

			pos = nilfs_find_next_zero_bit(bitmap, end, pos);

			if (pos >= end)

				break;

			if (!nilfs_set_bit_atomic(lock, pos, bitmap))

				return pos;

	} else {

		end = 0;

		} while (++pos < end);



		end = target;

	}



	for (i = 0, curr = end;

	     i < bsize;

	     i += BITS_PER_LONG, curr += BITS_PER_LONG) {

	/* wrap around */

		if (curr >= bsize)

			curr = 0;

		while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)

		       != ~0UL) {

			end = curr + BITS_PER_LONG;

			if (end > bsize)

				end = bsize;

			pos = nilfs_find_next_zero_bit(bitmap, end, curr);

			if (pos < end &&

			    !nilfs_set_bit_atomic(lock, pos, bitmap))

	for (pos = 0; pos < end; pos++) {

		pos = nilfs_find_next_zero_bit(bitmap, end, pos);

		if (pos >= end)

			break;

		if (!nilfs_set_bit_atomic(lock, pos, bitmap))

			return pos;

	}

	}



	return -ENOSPC;

}