Commit 94e39563 authored by Swapnil Ingle's avatar Swapnil Ingle Committed by Ben Walker
Browse files

nvmf/vfio_user: move cq_is_full() closer to caller 



Move cq_is_full() closer to its caller post_completion() and along with
fixing comments.

Signed-off-by: default avatarSwapnil Ingle <swapnil.ingle@nutanix.com>
Change-Id: I93262d1805f0f9f075c6946ed97cd3006ffba130
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/16415


Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
parent edfd7ff2

lib/nvmf/vfio_user.c

+48 −47
Original line number Diff line number Diff line
@@ -605,53 +605,6 @@ cq_tail_advance(struct nvmf_vfio_user_cq *cq) 
	}

}



static uint32_t

cq_free_slots(struct nvmf_vfio_user_cq *cq)

{

	uint32_t free_slots;



	assert(cq != NULL);



	if (cq->tail == cq->last_head) {

		free_slots = cq->size;

	} else if (cq->tail > cq->last_head) {

		free_slots = cq->size - (cq->tail - cq->last_head);

	} else {

		free_slots = cq->last_head - cq->tail;

	}

	assert(free_slots > 0);



	return free_slots - 1;

}



/*

 * As per NVMe Base spec 3.3.1.2.1, we are supposed to implement CQ flow

 * control: if there is no space in the CQ, we should wait until there is.

 *

 * In practice, we just fail the controller instead: as it happens, all host

 * implementations we care about right-size the CQ: this is required anyway for

 * NVMEoF support (see 3.3.2.8).

 *

 * Since reading the head doorbell is relatively expensive, we use the cached

 * value, so we only have to read it for real if it appears that we are full.

 */

static inline bool

cq_is_full(struct nvmf_vfio_user_cq *cq)

{

	uint32_t free_cq_slots;



	assert(cq != NULL);



	free_cq_slots = cq_free_slots(cq);



	if (spdk_unlikely(free_cq_slots == 0)) {

		cq->last_head = *cq_dbl_headp(cq);

		free_cq_slots = cq_free_slots(cq);

	}



	return free_cq_slots == 0;

}



static bool

io_q_exists(struct nvmf_vfio_user_ctrlr *vu_ctrlr, const uint16_t qid, const bool is_cq)

{
@@ -1724,6 +1677,46 @@ vfio_user_map_cmd(struct nvmf_vfio_user_ctrlr *ctrlr, struct spdk_nvmf_request * 
static int handle_cmd_req(struct nvmf_vfio_user_ctrlr *ctrlr, struct spdk_nvme_cmd *cmd,

			  struct nvmf_vfio_user_sq *sq);



static uint32_t

cq_free_slots(struct nvmf_vfio_user_cq *cq)

{

	uint32_t free_slots;



	assert(cq != NULL);



	if (cq->tail == cq->last_head) {

		free_slots = cq->size;

	} else if (cq->tail > cq->last_head) {

		free_slots = cq->size - (cq->tail - cq->last_head);

	} else {

		free_slots = cq->last_head - cq->tail;

	}

	assert(free_slots > 0);



	return free_slots - 1;

}



/*

 * Since reading the head doorbell is relatively expensive, we use the cached

 * value, so we only have to read it for real if it appears that we are full.

 */

static inline bool

cq_is_full(struct nvmf_vfio_user_cq *cq)

{

	uint32_t free_cq_slots;



	assert(cq != NULL);



	free_cq_slots = cq_free_slots(cq);



	if (spdk_unlikely(free_cq_slots == 0)) {

		cq->last_head = *cq_dbl_headp(cq);

		free_cq_slots = cq_free_slots(cq);

	}



	return free_cq_slots == 0;

}



/*

 * Posts a CQE in the completion queue.

 *
@@ -1753,6 +1746,14 @@ post_completion(struct nvmf_vfio_user_ctrlr *ctrlr, struct nvmf_vfio_user_cq *cq 
		assert(spdk_get_thread() == cq->group->group->thread);

	}



	/*

	 * As per NVMe Base spec 3.3.1.2.1, we are supposed to implement CQ flow

	 * control: if there is no space in the CQ, we should wait until there is.

	 *

	 * In practice, we just fail the controller instead: as it happens, all host

	 * implementations we care about right-size the CQ: this is required anyway for

	 * NVMEoF support (see 3.3.2.8).

	 */

	if (cq_is_full(cq)) {

		SPDK_ERRLOG("%s: cqid:%d full (tail=%d, head=%d)\n",

			    ctrlr_id(ctrlr), cq->qid, *cq_tailp(cq),