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net/mlx5: make Rx queue reinitialization safer

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The primary purpose of rxq_rehash() function is to stop and restart
reception on a queue after re-posting buffers. This may fail if the array
that temporarily stores existing buffers for reuse cannot be allocated.

Update rxq_rehash() to work on the target queue directly (not through a
template copy) and avoid this allocation.

rxq_alloc_elts() is modified accordingly to take buffers from an existing
queue directly and update their refcount.

Unlike rxq_rehash(), rxq_setup() must work on a temporary structure but
should not allocate new mbufs from the pool while reinitializing an
existing queue. This is achieved by using the refcount-aware
rxq_alloc_elts() before overwriting queue data.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Vasily Philipov <vasilyf@mellanox.com>
This commit is contained in:
Adrien Mazarguil 2016-06-24 15:18:03 +02:00 committed by Bruce Richardson
parent c6cb3a8fb5
commit cd9ea11454
1 changed files with 41 additions and 42 deletions
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83
drivers/net/mlx5/mlx5_rxq.c
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@ -642,7 +642,7 @@ priv_rehash_flows(struct priv *priv)
*/
static int
rxq_alloc_elts(struct rxq_ctrl *rxq_ctrl, unsigned int elts_n,
struct rte_mbuf **pool)
struct rte_mbuf *(*pool)[])
{
unsigned int i;
int ret = 0;
@ -654,9 +654,10 @@ rxq_alloc_elts(struct rxq_ctrl *rxq_ctrl, unsigned int elts_n,
&(*rxq_ctrl->rxq.wqes)[i];
if (pool != NULL) {
buf = *(pool++);
buf = (*pool)[i];
assert(buf != NULL);
rte_pktmbuf_reset(buf);
rte_pktmbuf_refcnt_update(buf, 1);
} else
buf = rte_pktmbuf_alloc(rxq_ctrl->rxq.mp);
if (buf == NULL) {
@ -781,7 +782,7 @@ rxq_cleanup(struct rxq_ctrl *rxq_ctrl)
}
/**
* Reconfigure a RX queue with new parameters.
* Reconfigure RX queue buffers.
*
* rxq_rehash() does not allocate mbufs, which, if not done from the right
* thread (such as a control thread), may corrupt the pool.
@ -798,67 +799,48 @@ rxq_cleanup(struct rxq_ctrl *rxq_ctrl)
int
rxq_rehash(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl)
{
struct rxq_ctrl tmpl = *rxq_ctrl;
unsigned int mbuf_n;
unsigned int desc_n;
struct rte_mbuf **pool;
unsigned int i, k;
unsigned int elts_n = rxq_ctrl->rxq.elts_n;
unsigned int i;
struct ibv_exp_wq_attr mod;
int err;
DEBUG("%p: rehashing queue %p", (void *)dev, (void *)rxq_ctrl);
/* Number of descriptors and mbufs currently allocated. */
desc_n = tmpl.rxq.elts_n;
mbuf_n = desc_n;
/* From now on, any failure will render the queue unusable.
* Reinitialize WQ. */
mod = (struct ibv_exp_wq_attr){
.attr_mask = IBV_EXP_WQ_ATTR_STATE,
.wq_state = IBV_EXP_WQS_RESET,
};
err = ibv_exp_modify_wq(tmpl.wq, &mod);
err = ibv_exp_modify_wq(rxq_ctrl->wq, &mod);
if (err) {
ERROR("%p: cannot reset WQ: %s", (void *)dev, strerror(err));
assert(err > 0);
return err;
}
/* Allocate pool. */
pool = rte_malloc(__func__, (mbuf_n * sizeof(*pool)), 0);
if (pool == NULL) {
ERROR("%p: cannot allocate memory", (void *)dev);
return ENOBUFS;
}
/* Snatch mbufs from original queue. */
k = 0;
for (i = 0; (i != desc_n); ++i)
pool[k++] = (*rxq_ctrl->rxq.elts)[i];
assert(k == mbuf_n);
rte_free(pool);
claim_zero(rxq_alloc_elts(rxq_ctrl, elts_n, rxq_ctrl->rxq.elts));
for (i = 0; i != elts_n; ++i) {
struct rte_mbuf *buf = (*rxq_ctrl->rxq.elts)[i];
assert(rte_mbuf_refcnt_read(buf) == 2);
rte_pktmbuf_free_seg(buf);
}
/* Change queue state to ready. */
mod = (struct ibv_exp_wq_attr){
.attr_mask = IBV_EXP_WQ_ATTR_STATE,
.wq_state = IBV_EXP_WQS_RDY,
};
err = ibv_exp_modify_wq(tmpl.wq, &mod);
err = ibv_exp_modify_wq(rxq_ctrl->wq, &mod);
if (err) {
ERROR("%p: WQ state to IBV_EXP_WQS_RDY failed: %s",
(void *)dev, strerror(err));
goto error;
}
/* Post SGEs. */
err = rxq_alloc_elts(&tmpl, desc_n, pool);
if (err) {
ERROR("%p: cannot reallocate WRs, aborting", (void *)dev);
rte_free(pool);
assert(err > 0);
return err;
}
/* Update doorbell counter. */
rxq_ctrl->rxq.rq_ci = desc_n;
rxq_ctrl->rxq.rq_ci = elts_n;
rte_wmb();
*rxq_ctrl->rxq.rq_db = htonl(rxq_ctrl->rxq.rq_ci);
error:
*rxq_ctrl = tmpl;
assert(err >= 0);
return err;
}
@ -868,24 +850,26 @@ rxq_rehash(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl)
*
* @param tmpl
* Pointer to RX queue control template.
* @param rxq_ctrl
* Pointer to RX queue control.
*
* @return
* 0 on success, errno value on failure.
*/
static inline int
rxq_setup(struct rxq_ctrl *tmpl, struct rxq_ctrl *rxq_ctrl)
rxq_setup(struct rxq_ctrl *tmpl)
{
struct ibv_cq *ibcq = tmpl->cq;
struct mlx5_cq *cq = to_mxxx(cq, cq);
struct mlx5_rwq *rwq = container_of(tmpl->wq, struct mlx5_rwq, wq);
struct rte_mbuf *(*elts)[tmpl->rxq.elts_n] =
rte_calloc_socket("RXQ", 1, sizeof(*elts), 0, tmpl->socket);
if (cq->cqe_sz != RTE_CACHE_LINE_SIZE) {
ERROR("Wrong MLX5_CQE_SIZE environment variable value: "
"it should be set to %u", RTE_CACHE_LINE_SIZE);
return EINVAL;
}
if (elts == NULL)
return ENOMEM;
tmpl->rxq.rq_db = rwq->rq.db;
tmpl->rxq.cqe_n = ibcq->cqe + 1;
tmpl->rxq.cq_ci = 0;
@ -897,9 +881,7 @@ rxq_setup(struct rxq_ctrl *tmpl, struct rxq_ctrl *rxq_ctrl)
tmpl->rxq.cqes =
(volatile struct mlx5_cqe (*)[])
(uintptr_t)cq->active_buf->buf;
tmpl->rxq.elts =
(struct rte_mbuf *(*)[tmpl->rxq.elts_n])
((uintptr_t)rxq_ctrl + sizeof(*rxq_ctrl));
tmpl->rxq.elts = elts;
return 0;
}
@ -947,6 +929,7 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl,
enum ibv_exp_query_intf_status status;
unsigned int mb_len = rte_pktmbuf_data_room_size(mp);
unsigned int cqe_n = desc - 1;
struct rte_mbuf *(*elts)[desc] = NULL;
int ret = 0;
(void)conf; /* Thresholds configuration (ignored). */
@ -1104,13 +1087,19 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl,
(void *)dev, strerror(ret));
goto error;
}
ret = rxq_setup(&tmpl, rxq_ctrl);
ret = rxq_setup(&tmpl);
if (ret) {
ERROR("%p: cannot initialize RX queue structure: %s",
(void *)dev, strerror(ret));
goto error;
}
ret = rxq_alloc_elts(&tmpl, desc, NULL);
/* Reuse buffers from original queue if possible. */
if (rxq_ctrl->rxq.elts_n) {
assert(rxq_ctrl->rxq.elts_n == desc);
assert(rxq_ctrl->rxq.elts != tmpl.rxq.elts);
ret = rxq_alloc_elts(&tmpl, desc, rxq_ctrl->rxq.elts);
} else
ret = rxq_alloc_elts(&tmpl, desc, NULL);
if (ret) {
ERROR("%p: RXQ allocation failed: %s",
(void *)dev, strerror(ret));
@ -1119,6 +1108,14 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl,
/* Clean up rxq in case we're reinitializing it. */
DEBUG("%p: cleaning-up old rxq just in case", (void *)rxq_ctrl);
rxq_cleanup(rxq_ctrl);
/* Move mbuf pointers to dedicated storage area in RX queue. */
elts = (void *)(rxq_ctrl + 1);
rte_memcpy(elts, tmpl.rxq.elts, sizeof(*elts));
#ifndef NDEBUG
memset(tmpl.rxq.elts, 0x55, sizeof(*elts));
#endif
rte_free(tmpl.rxq.elts);
tmpl.rxq.elts = elts;
*rxq_ctrl = tmpl;
/* Update doorbell counter. */
rxq_ctrl->rxq.rq_ci = desc;
@ -1128,7 +1125,9 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl,
assert(ret == 0);
return 0;
error:
elts = tmpl.rxq.elts;
rxq_cleanup(&tmpl);
rte_free(elts);
assert(ret > 0);
return ret;
}