Author: zbb Date: Wed May 11 13:38:29 2016 New Revision: 299446 URL: https://svnweb.freebsd.org/changeset/base/299446
Log: 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 Modified: head/sys/dev/vnic/nicvf_queues.c Modified: head/sys/dev/vnic/nicvf_queues.c ============================================================================== --- head/sys/dev/vnic/nicvf_queues.c Wed May 11 13:23:56 2016 (r299445) +++ head/sys/dev/vnic/nicvf_queues.c Wed May 11 13:38:29 2016 (r299446) @@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$"); #include <sys/proc.h> #include <sys/sockio.h> #include <sys/socket.h> +#include <sys/stdatomic.h> #include <sys/cpuset.h> #include <sys/lock.h> #include <sys/mutex.h> @@ -691,7 +692,7 @@ nicvf_rcv_pkt_handler(struct nicvf *nic, return (0); } -static int +static void nicvf_snd_pkt_handler(struct nicvf *nic, struct cmp_queue *cq, struct cqe_send_t *cqe_tx, int cqe_type) { @@ -702,15 +703,10 @@ nicvf_snd_pkt_handler(struct nicvf *nic, mbuf = NULL; sq = &nic->qs->sq[cqe_tx->sq_idx]; - /* Avoid blocking here since we hold a non-sleepable NICVF_CMP_LOCK */ - if (NICVF_TX_TRYLOCK(sq) == 0) - return (EAGAIN); hdr = (struct sq_hdr_subdesc *)GET_SQ_DESC(sq, cqe_tx->sqe_ptr); - if (hdr->subdesc_type != SQ_DESC_TYPE_HEADER) { - NICVF_TX_UNLOCK(sq); - return (0); - } + if (hdr->subdesc_type != SQ_DESC_TYPE_HEADER) + return; dprintf(nic->dev, "%s Qset #%d SQ #%d SQ ptr #%d subdesc count %d\n", @@ -728,9 +724,6 @@ nicvf_snd_pkt_handler(struct nicvf *nic, } nicvf_check_cqe_tx_errs(nic, cq, cqe_tx); - - NICVF_TX_UNLOCK(sq); - return (0); } static int @@ -788,16 +781,8 @@ nicvf_cq_intr_handler(struct nicvf *nic, work_done++; break; case CQE_TYPE_SEND: - cmp_err = nicvf_snd_pkt_handler(nic, cq, - (void *)cq_desc, CQE_TYPE_SEND); - if (__predict_false(cmp_err != 0)) { - /* - * Ups. Cannot finish now. - * Let's try again later. - */ - goto done; - } - + nicvf_snd_pkt_handler(nic, cq, (void *)cq_desc, + CQE_TYPE_SEND); tx_done++; break; case CQE_TYPE_INVALID: @@ -1085,7 +1070,7 @@ nicvf_init_snd_queue(struct nicvf *nic, sq->desc = sq->dmem.base; sq->head = sq->tail = 0; - sq->free_cnt = q_len - 1; + atomic_store_rel_int(&sq->free_cnt, q_len - 1); sq->thresh = SND_QUEUE_THRESH; sq->idx = qidx; sq->nic = nic; @@ -1676,7 +1661,7 @@ nicvf_get_sq_desc(struct snd_queue *sq, int qentry; qentry = sq->tail; - sq->free_cnt -= desc_cnt; + atomic_subtract_int(&sq->free_cnt, desc_cnt); sq->tail += desc_cnt; sq->tail &= (sq->dmem.q_len - 1); @@ -1688,7 +1673,7 @@ static void nicvf_put_sq_desc(struct snd_queue *sq, int desc_cnt) { - sq->free_cnt += desc_cnt; + atomic_add_int(&sq->free_cnt, desc_cnt); sq->head += desc_cnt; sq->head &= (sq->dmem.q_len - 1); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
