Fix deadlock in VNIC when using single CPU only
Number of free Tx descriptors does not need to be locked since it can be modified atomically between SND and CQ tasks. It will also block Tx routine from sending packets while CQ will not be able to free descriptors. Obtained from: Semihalf Sponsored by: Cavium Differential Revision: https://reviews.freebsd.org/D6266
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parent
46542fb652
commit
f6cdb4ceb3
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=299446
@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/proc.h>
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#include <sys/sockio.h>
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#include <sys/socket.h>
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#include <sys/stdatomic.h>
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#include <sys/cpuset.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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@ -691,7 +692,7 @@ nicvf_rcv_pkt_handler(struct nicvf *nic, struct cmp_queue *cq,
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return (0);
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}
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static int
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static void
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nicvf_snd_pkt_handler(struct nicvf *nic, struct cmp_queue *cq,
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struct cqe_send_t *cqe_tx, int cqe_type)
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{
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@ -702,15 +703,10 @@ nicvf_snd_pkt_handler(struct nicvf *nic, struct cmp_queue *cq,
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mbuf = NULL;
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sq = &nic->qs->sq[cqe_tx->sq_idx];
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/* Avoid blocking here since we hold a non-sleepable NICVF_CMP_LOCK */
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if (NICVF_TX_TRYLOCK(sq) == 0)
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return (EAGAIN);
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hdr = (struct sq_hdr_subdesc *)GET_SQ_DESC(sq, cqe_tx->sqe_ptr);
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if (hdr->subdesc_type != SQ_DESC_TYPE_HEADER) {
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NICVF_TX_UNLOCK(sq);
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return (0);
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}
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if (hdr->subdesc_type != SQ_DESC_TYPE_HEADER)
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return;
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dprintf(nic->dev,
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"%s Qset #%d SQ #%d SQ ptr #%d subdesc count %d\n",
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@ -728,9 +724,6 @@ nicvf_snd_pkt_handler(struct nicvf *nic, struct cmp_queue *cq,
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}
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nicvf_check_cqe_tx_errs(nic, cq, cqe_tx);
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NICVF_TX_UNLOCK(sq);
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return (0);
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}
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static int
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@ -788,16 +781,8 @@ nicvf_cq_intr_handler(struct nicvf *nic, uint8_t cq_idx)
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work_done++;
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break;
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case CQE_TYPE_SEND:
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cmp_err = nicvf_snd_pkt_handler(nic, cq,
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(void *)cq_desc, CQE_TYPE_SEND);
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if (__predict_false(cmp_err != 0)) {
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/*
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* Ups. Cannot finish now.
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* Let's try again later.
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*/
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goto done;
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}
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nicvf_snd_pkt_handler(nic, cq, (void *)cq_desc,
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CQE_TYPE_SEND);
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tx_done++;
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break;
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case CQE_TYPE_INVALID:
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@ -1085,7 +1070,7 @@ nicvf_init_snd_queue(struct nicvf *nic, struct snd_queue *sq, int q_len,
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sq->desc = sq->dmem.base;
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sq->head = sq->tail = 0;
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sq->free_cnt = q_len - 1;
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atomic_store_rel_int(&sq->free_cnt, q_len - 1);
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sq->thresh = SND_QUEUE_THRESH;
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sq->idx = qidx;
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sq->nic = nic;
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@ -1676,7 +1661,7 @@ nicvf_get_sq_desc(struct snd_queue *sq, int desc_cnt)
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int qentry;
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qentry = sq->tail;
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sq->free_cnt -= desc_cnt;
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atomic_subtract_int(&sq->free_cnt, desc_cnt);
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sq->tail += desc_cnt;
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sq->tail &= (sq->dmem.q_len - 1);
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@ -1688,7 +1673,7 @@ static void
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nicvf_put_sq_desc(struct snd_queue *sq, int desc_cnt)
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{
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sq->free_cnt += desc_cnt;
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atomic_add_int(&sq->free_cnt, desc_cnt);
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sq->head += desc_cnt;
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sq->head &= (sq->dmem.q_len - 1);
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}
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