Commit bfdc0edd authored by Bob Pearson's avatar Bob Pearson Committed by Jason Gunthorpe
Browse files

RDMA/rxe: Change mcg_lock to a _bh lock 

rxe_mcast.c currently uses _irqsave spinlocks for rxe->mcg_lock while
rxe_recv.c uses _bh spinlocks for the same lock.

As there is no case where the mcg_lock can be taken from an IRQ, change
these all to bh locks so we don't have confusing mismatched lock types on
the same spinlock.

Fixes: 6090a0c4 ("RDMA/rxe: Cleanup rxe_mcast.c")
Link: https://lore.kernel.org/r/20220504202817.98247-1-rpearsonhpe@gmail.com


Signed-off-by: default avatarBob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent a926a903

drivers/infiniband/sw/rxe/rxe_mcast.c

+15 −21
Original line number Diff line number Diff line
@@ -143,11 +143,10 @@ static struct rxe_mcg *__rxe_lookup_mcg(struct rxe_dev *rxe, 
struct rxe_mcg *rxe_lookup_mcg(struct rxe_dev *rxe, union ib_gid *mgid)

{

	struct rxe_mcg *mcg;

	unsigned long flags;



	spin_lock_irqsave(&rxe->mcg_lock, flags);

	spin_lock_bh(&rxe->mcg_lock);

	mcg = __rxe_lookup_mcg(rxe, mgid);

	spin_unlock_irqrestore(&rxe->mcg_lock, flags);

	spin_unlock_bh(&rxe->mcg_lock);



	return mcg;

}
@@ -189,7 +188,6 @@ static void __rxe_init_mcg(struct rxe_dev *rxe, union ib_gid *mgid, 
static struct rxe_mcg *rxe_get_mcg(struct rxe_dev *rxe, union ib_gid *mgid)

{

	struct rxe_mcg *mcg, *tmp;

	unsigned long flags;

	int err;



	if (rxe->attr.max_mcast_grp == 0)
@@ -211,18 +209,18 @@ static struct rxe_mcg *rxe_get_mcg(struct rxe_dev *rxe, union ib_gid *mgid) 
	if (!mcg)

		return ERR_PTR(-ENOMEM);



	spin_lock_irqsave(&rxe->mcg_lock, flags);

	spin_lock_bh(&rxe->mcg_lock);

	/* re-check to see if someone else just added it */

	tmp = __rxe_lookup_mcg(rxe, mgid);

	if (tmp) {

		spin_unlock_irqrestore(&rxe->mcg_lock, flags);

		spin_unlock_bh(&rxe->mcg_lock);

		atomic_dec(&rxe->mcg_num);

		kfree(mcg);

		return tmp;

	}



	__rxe_init_mcg(rxe, mgid, mcg);

	spin_unlock_irqrestore(&rxe->mcg_lock, flags);

	spin_unlock_bh(&rxe->mcg_lock);



	/* add mcast address outside of lock */

	err = rxe_mcast_add(rxe, mgid);
@@ -272,14 +270,12 @@ static void __rxe_destroy_mcg(struct rxe_mcg *mcg) 
 */

static void rxe_destroy_mcg(struct rxe_mcg *mcg)

{

	unsigned long flags;



	/* delete mcast address outside of lock */

	rxe_mcast_del(mcg->rxe, &mcg->mgid);



	spin_lock_irqsave(&mcg->rxe->mcg_lock, flags);

	spin_lock_bh(&mcg->rxe->mcg_lock);

	__rxe_destroy_mcg(mcg);

	spin_unlock_irqrestore(&mcg->rxe->mcg_lock, flags);

	spin_unlock_bh(&mcg->rxe->mcg_lock);

}



/**
@@ -334,25 +330,24 @@ static int rxe_attach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp) 
{

	struct rxe_dev *rxe = mcg->rxe;

	struct rxe_mca *mca, *tmp;

	unsigned long flags;

	int err;



	/* check to see if the qp is already a member of the group */

	spin_lock_irqsave(&rxe->mcg_lock, flags);

	spin_lock_bh(&rxe->mcg_lock);

	list_for_each_entry(mca, &mcg->qp_list, qp_list) {

		if (mca->qp == qp) {

			spin_unlock_irqrestore(&rxe->mcg_lock, flags);

			spin_unlock_bh(&rxe->mcg_lock);

			return 0;

		}

	}

	spin_unlock_irqrestore(&rxe->mcg_lock, flags);

	spin_unlock_bh(&rxe->mcg_lock);



	/* speculative alloc new mca without using GFP_ATOMIC */

	mca = kzalloc(sizeof(*mca), GFP_KERNEL);

	if (!mca)

		return -ENOMEM;



	spin_lock_irqsave(&rxe->mcg_lock, flags);

	spin_lock_bh(&rxe->mcg_lock);

	/* re-check to see if someone else just attached qp */

	list_for_each_entry(tmp, &mcg->qp_list, qp_list) {

		if (tmp->qp == qp) {
@@ -366,7 +361,7 @@ static int rxe_attach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp) 
	if (err)

		kfree(mca);

out:

	spin_unlock_irqrestore(&rxe->mcg_lock, flags);

	spin_unlock_bh(&rxe->mcg_lock);

	return err;

}
@@ -400,9 +395,8 @@ static int rxe_detach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp) 
{

	struct rxe_dev *rxe = mcg->rxe;

	struct rxe_mca *mca, *tmp;

	unsigned long flags;



	spin_lock_irqsave(&rxe->mcg_lock, flags);

	spin_lock_bh(&rxe->mcg_lock);

	list_for_each_entry_safe(mca, tmp, &mcg->qp_list, qp_list) {

		if (mca->qp == qp) {

			__rxe_cleanup_mca(mca, mcg);
@@ -416,13 +410,13 @@ static int rxe_detach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp) 
			if (atomic_read(&mcg->qp_num) <= 0)

				__rxe_destroy_mcg(mcg);



			spin_unlock_irqrestore(&rxe->mcg_lock, flags);

			spin_unlock_bh(&rxe->mcg_lock);

			return 0;

		}

	}



	/* we didn't find the qp on the list */

	spin_unlock_irqrestore(&rxe->mcg_lock, flags);

	spin_unlock_bh(&rxe->mcg_lock);

	return -EINVAL;

}