From 14d3a3b2498edadec344cb11e60e66091f5daf63 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 11 Dec 2015 11:53:03 -0800 Subject: [PATCH] IB: add a proper completion queue abstraction This adds an abstraction that allows ULPs to simply pass a completion object and completion callback with each submitted WR and let the RDMA core handle the nitty gritty details of how to handle completion interrupts and poll the CQ. In detail there is a new ib_cqe structure which just contains the completion callback, and which can be used to get at the containing object using container_of. It is pointed to by the WR and WC as an alternative to the wr_id field, similar to how many ULPs already use the field to store a pointer using casts. A driver using the new completion callbacks allocates it's CQs using the new ib_create_cq API, which in addition to the number of CQEs and the completion vectors also takes a mode on how we poll for CQEs. Three modes are available: direct for drivers that never take CQ interrupts and just poll for them, softirq to poll from softirq context using the to be renamed blk-iopoll infrastructure which takes care of rearming and budgeting, or a workqueue for consumer who want to be called from user context. Thanks a lot to Sagi Grimberg who helped reviewing the API, wrote the current version of the workqueue code because my two previous attempts sucked too much and converted the iSER initiator to the new API. Signed-off-by: Christoph Hellwig --- drivers/infiniband/Kconfig | 1 + drivers/infiniband/core/Makefile | 2 +- drivers/infiniband/core/cq.c | 209 ++++++++++++++++++++++++ drivers/infiniband/core/device.c | 15 +- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 2 +- drivers/infiniband/ulp/srp/ib_srp.c | 6 +- include/rdma/ib_verbs.h | 38 ++++- 7 files changed, 264 insertions(+), 9 deletions(-) create mode 100644 drivers/infiniband/core/cq.c diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig index aa26f3c3416b..282ec0b664fe 100644 --- a/drivers/infiniband/Kconfig +++ b/drivers/infiniband/Kconfig @@ -5,6 +5,7 @@ menuconfig INFINIBAND depends on NET depends on INET depends on m || IPV6 != m + select IRQ_POLL ---help--- Core support for InfiniBand (IB). Make sure to also select any protocols you wish to use as well as drivers for your diff --git a/drivers/infiniband/core/Makefile b/drivers/infiniband/core/Makefile index d43a8994ac5c..ae48d874012f 100644 --- a/drivers/infiniband/core/Makefile +++ b/drivers/infiniband/core/Makefile @@ -8,7 +8,7 @@ obj-$(CONFIG_INFINIBAND_USER_MAD) += ib_umad.o obj-$(CONFIG_INFINIBAND_USER_ACCESS) += ib_uverbs.o ib_ucm.o \ $(user_access-y) -ib_core-y := packer.o ud_header.o verbs.o sysfs.o \ +ib_core-y := packer.o ud_header.o verbs.o cq.o sysfs.o \ device.o fmr_pool.o cache.o netlink.o \ roce_gid_mgmt.o ib_core-$(CONFIG_INFINIBAND_USER_MEM) += umem.o diff --git a/drivers/infiniband/core/cq.c b/drivers/infiniband/core/cq.c new file mode 100644 index 000000000000..a754fc727de5 --- /dev/null +++ b/drivers/infiniband/core/cq.c @@ -0,0 +1,209 @@ +/* + * Copyright (c) 2015 HGST, a Western Digital Company. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include +#include +#include +#include + +/* # of WCs to poll for with a single call to ib_poll_cq */ +#define IB_POLL_BATCH 16 + +/* # of WCs to iterate over before yielding */ +#define IB_POLL_BUDGET_IRQ 256 +#define IB_POLL_BUDGET_WORKQUEUE 65536 + +#define IB_POLL_FLAGS \ + (IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS) + +static int __ib_process_cq(struct ib_cq *cq, int budget) +{ + int i, n, completed = 0; + + while ((n = ib_poll_cq(cq, IB_POLL_BATCH, cq->wc)) > 0) { + for (i = 0; i < n; i++) { + struct ib_wc *wc = &cq->wc[i]; + + if (wc->wr_cqe) + wc->wr_cqe->done(cq, wc); + else + WARN_ON_ONCE(wc->status == IB_WC_SUCCESS); + } + + completed += n; + + if (n != IB_POLL_BATCH || + (budget != -1 && completed >= budget)) + break; + } + + return completed; +} + +/** + * ib_process_direct_cq - process a CQ in caller context + * @cq: CQ to process + * @budget: number of CQEs to poll for + * + * This function is used to process all outstanding CQ entries on a + * %IB_POLL_DIRECT CQ. It does not offload CQ processing to a different + * context and does not ask for completion interrupts from the HCA. + * + * Note: for compatibility reasons -1 can be passed in %budget for unlimited + * polling. Do not use this feature in new code, it will be removed soon. + */ +int ib_process_cq_direct(struct ib_cq *cq, int budget) +{ + WARN_ON_ONCE(cq->poll_ctx != IB_POLL_DIRECT); + + return __ib_process_cq(cq, budget); +} +EXPORT_SYMBOL(ib_process_cq_direct); + +static void ib_cq_completion_direct(struct ib_cq *cq, void *private) +{ + WARN_ONCE(1, "got unsolicited completion for CQ 0x%p\n", cq); +} + +static int ib_poll_handler(struct irq_poll *iop, int budget) +{ + struct ib_cq *cq = container_of(iop, struct ib_cq, iop); + int completed; + + completed = __ib_process_cq(cq, budget); + if (completed < budget) { + irq_poll_complete(&cq->iop); + if (ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) + irq_poll_sched(&cq->iop); + } + + return completed; +} + +static void ib_cq_completion_softirq(struct ib_cq *cq, void *private) +{ + irq_poll_sched(&cq->iop); +} + +static void ib_cq_poll_work(struct work_struct *work) +{ + struct ib_cq *cq = container_of(work, struct ib_cq, work); + int completed; + + completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE); + if (completed >= IB_POLL_BUDGET_WORKQUEUE || + ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) + queue_work(ib_comp_wq, &cq->work); +} + +static void ib_cq_completion_workqueue(struct ib_cq *cq, void *private) +{ + queue_work(ib_comp_wq, &cq->work); +} + +/** + * ib_alloc_cq - allocate a completion queue + * @dev: device to allocate the CQ for + * @private: driver private data, accessible from cq->cq_context + * @nr_cqe: number of CQEs to allocate + * @comp_vector: HCA completion vectors for this CQ + * @poll_ctx: context to poll the CQ from. + * + * This is the proper interface to allocate a CQ for in-kernel users. A + * CQ allocated with this interface will automatically be polled from the + * specified context. The ULP needs must use wr->wr_cqe instead of wr->wr_id + * to use this CQ abstraction. + */ +struct ib_cq *ib_alloc_cq(struct ib_device *dev, void *private, + int nr_cqe, int comp_vector, enum ib_poll_context poll_ctx) +{ + struct ib_cq_init_attr cq_attr = { + .cqe = nr_cqe, + .comp_vector = comp_vector, + }; + struct ib_cq *cq; + int ret = -ENOMEM; + + cq = dev->create_cq(dev, &cq_attr, NULL, NULL); + if (IS_ERR(cq)) + return cq; + + cq->device = dev; + cq->uobject = NULL; + cq->event_handler = NULL; + cq->cq_context = private; + cq->poll_ctx = poll_ctx; + atomic_set(&cq->usecnt, 0); + + cq->wc = kmalloc_array(IB_POLL_BATCH, sizeof(*cq->wc), GFP_KERNEL); + if (!cq->wc) + goto out_destroy_cq; + + switch (cq->poll_ctx) { + case IB_POLL_DIRECT: + cq->comp_handler = ib_cq_completion_direct; + break; + case IB_POLL_SOFTIRQ: + cq->comp_handler = ib_cq_completion_softirq; + + irq_poll_init(&cq->iop, IB_POLL_BUDGET_IRQ, ib_poll_handler); + ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); + break; + case IB_POLL_WORKQUEUE: + cq->comp_handler = ib_cq_completion_workqueue; + INIT_WORK(&cq->work, ib_cq_poll_work); + ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); + break; + default: + ret = -EINVAL; + goto out_free_wc; + } + + return cq; + +out_free_wc: + kfree(cq->wc); +out_destroy_cq: + cq->device->destroy_cq(cq); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(ib_alloc_cq); + +/** + * ib_free_cq - free a completion queue + * @cq: completion queue to free. + */ +void ib_free_cq(struct ib_cq *cq) +{ + int ret; + + if (WARN_ON_ONCE(atomic_read(&cq->usecnt))) + return; + + switch (cq->poll_ctx) { + case IB_POLL_DIRECT: + break; + case IB_POLL_SOFTIRQ: + irq_poll_disable(&cq->iop); + break; + case IB_POLL_WORKQUEUE: + flush_work(&cq->work); + break; + default: + WARN_ON_ONCE(1); + } + + kfree(cq->wc); + ret = cq->device->destroy_cq(cq); + WARN_ON_ONCE(ret); +} +EXPORT_SYMBOL(ib_free_cq); diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 179e8134d57f..6421d2317b6f 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -58,6 +58,7 @@ struct ib_client_data { bool going_down; }; +struct workqueue_struct *ib_comp_wq; struct workqueue_struct *ib_wq; EXPORT_SYMBOL_GPL(ib_wq); @@ -954,10 +955,18 @@ static int __init ib_core_init(void) if (!ib_wq) return -ENOMEM; + ib_comp_wq = alloc_workqueue("ib-comp-wq", + WQ_UNBOUND | WQ_HIGHPRI | WQ_MEM_RECLAIM, + WQ_UNBOUND_MAX_ACTIVE); + if (!ib_comp_wq) { + ret = -ENOMEM; + goto err; + } + ret = class_register(&ib_class); if (ret) { printk(KERN_WARNING "Couldn't create InfiniBand device class\n"); - goto err; + goto err_comp; } ret = ibnl_init(); @@ -972,7 +981,8 @@ static int __init ib_core_init(void) err_sysfs: class_unregister(&ib_class); - +err_comp: + destroy_workqueue(ib_comp_wq); err: destroy_workqueue(ib_wq); return ret; @@ -983,6 +993,7 @@ static void __exit ib_core_cleanup(void) ib_cache_cleanup(); ibnl_cleanup(); class_unregister(&ib_class); + destroy_workqueue(ib_comp_wq); /* Make sure that any pending umem accounting work is done. */ destroy_workqueue(ib_wq); } diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c index 3ae9726efb98..9b014f153442 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -70,7 +70,6 @@ static struct ib_qp_attr ipoib_cm_err_attr = { #define IPOIB_CM_RX_DRAIN_WRID 0xffffffff static struct ib_send_wr ipoib_cm_rx_drain_wr = { - .wr_id = IPOIB_CM_RX_DRAIN_WRID, .opcode = IB_WR_SEND, }; @@ -223,6 +222,7 @@ static void ipoib_cm_start_rx_drain(struct ipoib_dev_priv *priv) * error" WC will be immediately generated for each WR we post. */ p = list_entry(priv->cm.rx_flush_list.next, typeof(*p), list); + ipoib_cm_rx_drain_wr.wr_id = IPOIB_CM_RX_DRAIN_WRID; if (ib_post_send(p->qp, &ipoib_cm_rx_drain_wr, &bad_wr)) ipoib_warn(priv, "failed to post drain wr\n"); diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index 9909022dc6c3..9f1cb3c5e3c3 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -457,10 +457,11 @@ static struct srp_fr_pool *srp_alloc_fr_pool(struct srp_target_port *target) static void srp_destroy_qp(struct srp_rdma_ch *ch) { static struct ib_qp_attr attr = { .qp_state = IB_QPS_ERR }; - static struct ib_recv_wr wr = { .wr_id = SRP_LAST_WR_ID }; + static struct ib_recv_wr wr = { 0 }; struct ib_recv_wr *bad_wr; int ret; + wr.wr_id = SRP_LAST_WR_ID; /* Destroying a QP and reusing ch->done is only safe if not connected */ WARN_ON_ONCE(ch->connected); @@ -1042,13 +1043,14 @@ static int srp_inv_rkey(struct srp_rdma_ch *ch, u32 rkey) struct ib_send_wr *bad_wr; struct ib_send_wr wr = { .opcode = IB_WR_LOCAL_INV, - .wr_id = LOCAL_INV_WR_ID_MASK, .next = NULL, .num_sge = 0, .send_flags = 0, .ex.invalidate_rkey = rkey, }; + wr.wr_id = LOCAL_INV_WR_ID_MASK; + return ib_post_send(ch->qp, &wr, &bad_wr); } diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 9a68a19532ba..131dd4b5176c 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -49,6 +49,7 @@ #include #include #include +#include #include #include @@ -56,6 +57,7 @@ #include extern struct workqueue_struct *ib_wq; +extern struct workqueue_struct *ib_comp_wq; union ib_gid { u8 raw[16]; @@ -758,7 +760,10 @@ enum ib_wc_flags { }; struct ib_wc { - u64 wr_id; + union { + u64 wr_id; + struct ib_cqe *wr_cqe; + }; enum ib_wc_status status; enum ib_wc_opcode opcode; u32 vendor_err; @@ -1079,9 +1084,16 @@ struct ib_mw_bind_info { int mw_access_flags; }; +struct ib_cqe { + void (*done)(struct ib_cq *cq, struct ib_wc *wc); +}; + struct ib_send_wr { struct ib_send_wr *next; - u64 wr_id; + union { + u64 wr_id; + struct ib_cqe *wr_cqe; + }; struct ib_sge *sg_list; int num_sge; enum ib_wr_opcode opcode; @@ -1175,7 +1187,10 @@ static inline struct ib_sig_handover_wr *sig_handover_wr(struct ib_send_wr *wr) struct ib_recv_wr { struct ib_recv_wr *next; - u64 wr_id; + union { + u64 wr_id; + struct ib_cqe *wr_cqe; + }; struct ib_sge *sg_list; int num_sge; }; @@ -1306,6 +1321,12 @@ struct ib_ah { typedef void (*ib_comp_handler)(struct ib_cq *cq, void *cq_context); +enum ib_poll_context { + IB_POLL_DIRECT, /* caller context, no hw completions */ + IB_POLL_SOFTIRQ, /* poll from softirq context */ + IB_POLL_WORKQUEUE, /* poll from workqueue */ +}; + struct ib_cq { struct ib_device *device; struct ib_uobject *uobject; @@ -1314,6 +1335,12 @@ struct ib_cq { void *cq_context; int cqe; atomic_t usecnt; /* count number of work queues */ + enum ib_poll_context poll_ctx; + struct ib_wc *wc; + union { + struct irq_poll iop; + struct work_struct work; + }; }; struct ib_srq { @@ -2453,6 +2480,11 @@ static inline int ib_post_recv(struct ib_qp *qp, return qp->device->post_recv(qp, recv_wr, bad_recv_wr); } +struct ib_cq *ib_alloc_cq(struct ib_device *dev, void *private, + int nr_cqe, int comp_vector, enum ib_poll_context poll_ctx); +void ib_free_cq(struct ib_cq *cq); +int ib_process_cq_direct(struct ib_cq *cq, int budget); + /** * ib_create_cq - Creates a CQ on the specified device. * @device: The device on which to create the CQ. -- 2.20.1