Commit 2717eb35 authored by Fedor Pchelkin's avatar Fedor Pchelkin Committed by Carlos Maiolino
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xfs: use a proper variable name and type for storing a comparison result 



Perhaps that's just my silly imagination but 'diff' doesn't look good for
the name of a variable to hold a result of a three-way-comparison
(-1, 0, 1) which is what ->cmp_key_with_cur() does. It implies to contain
an actual difference between the two integer variables but that's not true
anymore after recent refactoring.

Declaring it as int64_t is also misleading now. Plain integer type is
more than enough.

Found by Linux Verification Center (linuxtesting.org).

Signed-off-by: default avatarFedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent 734b871d

fs/xfs/libxfs/xfs_btree.c

+12 −11
Original line number Diff line number Diff line
@@ -1985,7 +1985,7 @@ xfs_btree_lookup( 
	int			*stat)	/* success/failure */

{

	struct xfs_btree_block	*block;	/* current btree block */

	int64_t			diff;	/* difference for the current key */

	int			cmp_r;	/* current key comparison result */

	int			error;	/* error return value */

	int			keyno;	/* current key number */

	int			level;	/* level in the btree */
@@ -2013,13 +2013,13 @@ xfs_btree_lookup( 
	 * on the lookup record, then follow the corresponding block

	 * pointer down to the next level.

	 */

	for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {

	for (level = cur->bc_nlevels - 1, cmp_r = 1; level >= 0; level--) {

		/* Get the block we need to do the lookup on. */

		error = xfs_btree_lookup_get_block(cur, level, pp, &block);

		if (error)

			goto error0;



		if (diff == 0) {

		if (cmp_r == 0) {

			/*

			 * If we already had a key match at a higher level, we

			 * know we need to use the first entry in this block.
@@ -2065,15 +2065,16 @@ xfs_btree_lookup( 
						keyno, block, &key);



				/*

				 * Compute difference to get next direction:

				 * Compute comparison result to get next

				 * direction:

				 *  - less than, move right

				 *  - greater than, move left

				 *  - equal, we're done

				 */

				diff = cur->bc_ops->cmp_key_with_cur(cur, kp);

				if (diff < 0)

				cmp_r = cur->bc_ops->cmp_key_with_cur(cur, kp);

				if (cmp_r < 0)

					low = keyno + 1;

				else if (diff > 0)

				else if (cmp_r > 0)

					high = keyno - 1;

				else

					break;
@@ -2089,7 +2090,7 @@ xfs_btree_lookup( 
			 * If we moved left, need the previous key number,

			 * unless there isn't one.

			 */

			if (diff > 0 && --keyno < 1)

			if (cmp_r > 0 && --keyno < 1)

				keyno = 1;

			pp = xfs_btree_ptr_addr(cur, keyno, block);
@@ -2102,7 +2103,7 @@ xfs_btree_lookup( 
	}



	/* Done with the search. See if we need to adjust the results. */

	if (dir != XFS_LOOKUP_LE && diff < 0) {

	if (dir != XFS_LOOKUP_LE && cmp_r < 0) {

		keyno++;

		/*

		 * If ge search and we went off the end of the block, but it's
@@ -2125,14 +2126,14 @@ xfs_btree_lookup( 
			*stat = 1;

			return 0;

		}

	} else if (dir == XFS_LOOKUP_LE && diff > 0)

	} else if (dir == XFS_LOOKUP_LE && cmp_r > 0)

		keyno--;

	cur->bc_levels[0].ptr = keyno;



	/* Return if we succeeded or not. */

	if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))

		*stat = 0;

	else if (dir != XFS_LOOKUP_EQ || diff == 0)

	else if (dir != XFS_LOOKUP_EQ || cmp_r == 0)

		*stat = 1;

	else

		*stat = 0;