Commit 675e2694 authored by Christophe JAILLET's avatar Christophe JAILLET Committed by Jason Gunthorpe
Browse files

IB/mthca: Use non-atomic bitmap functions when possible in 'mthca_mr.c' 

In 'mthca_buddy_init()', the 'buddy->bits[n]' bitmap has just been
allocated, so no concurrent accesses can occur.

The other accesses to the 'buddy->bits[n]' bitmap are protected by the
'buddy->lock' spinlock, so no concurrent accesses can occur.

So prefer the non-atomic '__[set|clear]_bit()' functions to save a few
cycles.

Link: https://lore.kernel.org/r/a19b88ccdbc03972fd97306b998731814283041f.1637785902.git.christophe.jaillet@wanadoo.fr


Signed-off-by: default avatarChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 19453f34

drivers/infiniband/hw/mthca/mthca_mr.c

+5 −5
Original line number Diff line number Diff line
@@ -101,13 +101,13 @@ static u32 mthca_buddy_alloc(struct mthca_buddy *buddy, int order) 
	return -1;



 found:

	clear_bit(seg, buddy->bits[o]);

	__clear_bit(seg, buddy->bits[o]);

	--buddy->num_free[o];



	while (o > order) {

		--o;

		seg <<= 1;

		set_bit(seg ^ 1, buddy->bits[o]);

		__set_bit(seg ^ 1, buddy->bits[o]);

		++buddy->num_free[o];

	}
@@ -125,13 +125,13 @@ static void mthca_buddy_free(struct mthca_buddy *buddy, u32 seg, int order) 
	spin_lock(&buddy->lock);



	while (test_bit(seg ^ 1, buddy->bits[order])) {

		clear_bit(seg ^ 1, buddy->bits[order]);

		__clear_bit(seg ^ 1, buddy->bits[order]);

		--buddy->num_free[order];

		seg >>= 1;

		++order;

	}



	set_bit(seg, buddy->bits[order]);

	__set_bit(seg, buddy->bits[order]);

	++buddy->num_free[order];



	spin_unlock(&buddy->lock);
@@ -158,7 +158,7 @@ static int mthca_buddy_init(struct mthca_buddy *buddy, int max_order) 
			goto err_out_free;

	}



	set_bit(0, buddy->bits[buddy->max_order]);

	__set_bit(0, buddy->bits[buddy->max_order]);

	buddy->num_free[buddy->max_order] = 1;



	return 0;