1 /* 2 * Copyright (c) 2015 HGST, a Western Digital Company. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 */ 13 #include <linux/module.h> 14 #include <linux/err.h> 15 #include <linux/slab.h> 16 #include <rdma/ib_verbs.h> 17 18 /* # of WCs to poll for with a single call to ib_poll_cq */ 19 #define IB_POLL_BATCH 16 20 #define IB_POLL_BATCH_DIRECT 8 21 22 /* # of WCs to iterate over before yielding */ 23 #define IB_POLL_BUDGET_IRQ 256 24 #define IB_POLL_BUDGET_WORKQUEUE 65536 25 26 #define IB_POLL_FLAGS \ 27 (IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS) 28 29 static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *wcs, 30 int batch) 31 { 32 int i, n, completed = 0; 33 34 /* 35 * budget might be (-1) if the caller does not 36 * want to bound this call, thus we need unsigned 37 * minimum here. 38 */ 39 while ((n = ib_poll_cq(cq, min_t(u32, batch, 40 budget - completed), wcs)) > 0) { 41 for (i = 0; i < n; i++) { 42 struct ib_wc *wc = &wcs[i]; 43 44 if (wc->wr_cqe) 45 wc->wr_cqe->done(cq, wc); 46 else 47 WARN_ON_ONCE(wc->status == IB_WC_SUCCESS); 48 } 49 50 completed += n; 51 52 if (n != batch || (budget != -1 && completed >= budget)) 53 break; 54 } 55 56 return completed; 57 } 58 59 /** 60 * ib_process_direct_cq - process a CQ in caller context 61 * @cq: CQ to process 62 * @budget: number of CQEs to poll for 63 * 64 * This function is used to process all outstanding CQ entries. 65 * It does not offload CQ processing to a different context and does 66 * not ask for completion interrupts from the HCA. 67 * Using direct processing on CQ with non IB_POLL_DIRECT type may trigger 68 * concurrent processing. 69 * 70 * Note: do not pass -1 as %budget unless it is guaranteed that the number 71 * of completions that will be processed is small. 72 */ 73 int ib_process_cq_direct(struct ib_cq *cq, int budget) 74 { 75 struct ib_wc wcs[IB_POLL_BATCH_DIRECT]; 76 77 return __ib_process_cq(cq, budget, wcs, IB_POLL_BATCH_DIRECT); 78 } 79 EXPORT_SYMBOL(ib_process_cq_direct); 80 81 static void ib_cq_completion_direct(struct ib_cq *cq, void *private) 82 { 83 WARN_ONCE(1, "got unsolicited completion for CQ 0x%p\n", cq); 84 } 85 86 static int ib_poll_handler(struct irq_poll *iop, int budget) 87 { 88 struct ib_cq *cq = container_of(iop, struct ib_cq, iop); 89 int completed; 90 91 completed = __ib_process_cq(cq, budget, cq->wc, IB_POLL_BATCH); 92 if (completed < budget) { 93 irq_poll_complete(&cq->iop); 94 if (ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) 95 irq_poll_sched(&cq->iop); 96 } 97 98 return completed; 99 } 100 101 static void ib_cq_completion_softirq(struct ib_cq *cq, void *private) 102 { 103 irq_poll_sched(&cq->iop); 104 } 105 106 static void ib_cq_poll_work(struct work_struct *work) 107 { 108 struct ib_cq *cq = container_of(work, struct ib_cq, work); 109 int completed; 110 111 completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE, cq->wc, 112 IB_POLL_BATCH); 113 if (completed >= IB_POLL_BUDGET_WORKQUEUE || 114 ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) 115 queue_work(cq->comp_wq, &cq->work); 116 } 117 118 static void ib_cq_completion_workqueue(struct ib_cq *cq, void *private) 119 { 120 queue_work(cq->comp_wq, &cq->work); 121 } 122 123 /** 124 * __ib_alloc_cq - allocate a completion queue 125 * @dev: device to allocate the CQ for 126 * @private: driver private data, accessible from cq->cq_context 127 * @nr_cqe: number of CQEs to allocate 128 * @comp_vector: HCA completion vectors for this CQ 129 * @poll_ctx: context to poll the CQ from. 130 * @caller: module owner name. 131 * 132 * This is the proper interface to allocate a CQ for in-kernel users. A 133 * CQ allocated with this interface will automatically be polled from the 134 * specified context. The ULP must use wr->wr_cqe instead of wr->wr_id 135 * to use this CQ abstraction. 136 */ 137 struct ib_cq *__ib_alloc_cq(struct ib_device *dev, void *private, 138 int nr_cqe, int comp_vector, 139 enum ib_poll_context poll_ctx, const char *caller) 140 { 141 struct ib_cq_init_attr cq_attr = { 142 .cqe = nr_cqe, 143 .comp_vector = comp_vector, 144 }; 145 struct ib_cq *cq; 146 int ret = -ENOMEM; 147 148 cq = dev->ops.create_cq(dev, &cq_attr, NULL, NULL); 149 if (IS_ERR(cq)) 150 return cq; 151 152 cq->device = dev; 153 cq->uobject = NULL; 154 cq->event_handler = NULL; 155 cq->cq_context = private; 156 cq->poll_ctx = poll_ctx; 157 atomic_set(&cq->usecnt, 0); 158 159 cq->wc = kmalloc_array(IB_POLL_BATCH, sizeof(*cq->wc), GFP_KERNEL); 160 if (!cq->wc) 161 goto out_destroy_cq; 162 163 cq->res.type = RDMA_RESTRACK_CQ; 164 rdma_restrack_set_task(&cq->res, caller); 165 rdma_restrack_kadd(&cq->res); 166 167 switch (cq->poll_ctx) { 168 case IB_POLL_DIRECT: 169 cq->comp_handler = ib_cq_completion_direct; 170 break; 171 case IB_POLL_SOFTIRQ: 172 cq->comp_handler = ib_cq_completion_softirq; 173 174 irq_poll_init(&cq->iop, IB_POLL_BUDGET_IRQ, ib_poll_handler); 175 ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); 176 break; 177 case IB_POLL_WORKQUEUE: 178 case IB_POLL_UNBOUND_WORKQUEUE: 179 cq->comp_handler = ib_cq_completion_workqueue; 180 INIT_WORK(&cq->work, ib_cq_poll_work); 181 ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); 182 cq->comp_wq = (cq->poll_ctx == IB_POLL_WORKQUEUE) ? 183 ib_comp_wq : ib_comp_unbound_wq; 184 break; 185 default: 186 ret = -EINVAL; 187 goto out_free_wc; 188 } 189 190 return cq; 191 192 out_free_wc: 193 kfree(cq->wc); 194 rdma_restrack_del(&cq->res); 195 out_destroy_cq: 196 cq->device->ops.destroy_cq(cq); 197 return ERR_PTR(ret); 198 } 199 EXPORT_SYMBOL(__ib_alloc_cq); 200 201 /** 202 * ib_free_cq - free a completion queue 203 * @cq: completion queue to free. 204 */ 205 void ib_free_cq(struct ib_cq *cq) 206 { 207 int ret; 208 209 if (WARN_ON_ONCE(atomic_read(&cq->usecnt))) 210 return; 211 212 switch (cq->poll_ctx) { 213 case IB_POLL_DIRECT: 214 break; 215 case IB_POLL_SOFTIRQ: 216 irq_poll_disable(&cq->iop); 217 break; 218 case IB_POLL_WORKQUEUE: 219 case IB_POLL_UNBOUND_WORKQUEUE: 220 cancel_work_sync(&cq->work); 221 break; 222 default: 223 WARN_ON_ONCE(1); 224 } 225 226 kfree(cq->wc); 227 rdma_restrack_del(&cq->res); 228 ret = cq->device->ops.destroy_cq(cq); 229 WARN_ON_ONCE(ret); 230 } 231 EXPORT_SYMBOL(ib_free_cq); 232