Commit 732d41c5 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/cma: Make the locking for automatic state transition more clear 

Re-organize things so the state variable is not read unlocked. The first
attempt to go directly from ADDR_BOUND immediately tells us if the ID is
already bound, if we can't do that then the attempt inside
rdma_bind_addr() to go from IDLE to ADDR_BOUND confirms the ID needs
binding.

Link: https://lore.kernel.org/r/20200902081122.745412-3-leon@kernel.org


Signed-off-by: default avatarLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 2a7cec53

drivers/infiniband/core/cma.c

+45 −22
Original line number Diff line number Diff line
@@ -3248,33 +3248,55 @@ static int cma_bind_addr(struct rdma_cm_id *id, struct sockaddr *src_addr, 
	return rdma_bind_addr(id, src_addr);

}



int rdma_resolve_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,

		      const struct sockaddr *dst_addr, unsigned long timeout_ms)

/*

 * If required, resolve the source address for bind and leave the id_priv in

 * state RDMA_CM_ADDR_BOUND. This oddly uses the state to determine the prior

 * calls made by ULP, a previously bound ID will not be re-bound and src_addr is

 * ignored.

 */

static int resolve_prepare_src(struct rdma_id_private *id_priv,

			       struct sockaddr *src_addr,

			       const struct sockaddr *dst_addr)

{

	struct rdma_id_private *id_priv;

	int ret;



	id_priv = container_of(id, struct rdma_id_private, id);

	memcpy(cma_dst_addr(id_priv), dst_addr, rdma_addr_size(dst_addr));

	if (id_priv->state == RDMA_CM_IDLE) {

		ret = cma_bind_addr(id, src_addr, dst_addr);

		if (ret) {

			memset(cma_dst_addr(id_priv), 0,

			       rdma_addr_size(dst_addr));

			return ret;

	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_ADDR_QUERY)) {

		/* For a well behaved ULP state will be RDMA_CM_IDLE */

		ret = cma_bind_addr(&id_priv->id, src_addr, dst_addr);

		if (ret)

			goto err_dst;

		if (WARN_ON(!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND,

					   RDMA_CM_ADDR_QUERY))) {

			ret = -EINVAL;

			goto err_dst;

		}

	}



	if (cma_family(id_priv) != dst_addr->sa_family) {

		memset(cma_dst_addr(id_priv), 0, rdma_addr_size(dst_addr));

		return -EINVAL;

		ret = -EINVAL;

		goto err_state;

	}

	return 0;



	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_ADDR_QUERY)) {

err_state:

	cma_comp_exch(id_priv, RDMA_CM_ADDR_QUERY, RDMA_CM_ADDR_BOUND);

err_dst:

	memset(cma_dst_addr(id_priv), 0, rdma_addr_size(dst_addr));

		return -EINVAL;

	return ret;

}



int rdma_resolve_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,

		      const struct sockaddr *dst_addr, unsigned long timeout_ms)

{

	struct rdma_id_private *id_priv =

		container_of(id, struct rdma_id_private, id);

	int ret;



	ret = resolve_prepare_src(id_priv, src_addr, dst_addr);

	if (ret)

		return ret;



	if (cma_any_addr(dst_addr)) {

		ret = cma_resolve_loopback(id_priv);

	} else {
@@ -3646,19 +3668,20 @@ static int cma_check_linklocal(struct rdma_dev_addr *dev_addr, 


int rdma_listen(struct rdma_cm_id *id, int backlog)

{

	struct rdma_id_private *id_priv;

	struct rdma_id_private *id_priv =

		container_of(id, struct rdma_id_private, id);

	int ret;



	id_priv = container_of(id, struct rdma_id_private, id);

	if (id_priv->state == RDMA_CM_IDLE) {

	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_LISTEN)) {

		/* For a well behaved ULP state will be RDMA_CM_IDLE */

		id->route.addr.src_addr.ss_family = AF_INET;

		ret = rdma_bind_addr(id, cma_src_addr(id_priv));

		if (ret)

			return ret;

	}



	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_LISTEN))

		if (WARN_ON(!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND,

					   RDMA_CM_LISTEN)))

			return -EINVAL;

	}



	if (id_priv->reuseaddr) {

		ret = cma_bind_listen(id_priv);