drivers/dma/idxd/submit.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
   3 #include <linux/init.h>
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/pci.h>
   7 #include <uapi/linux/idxd.h>
   8 #include "idxd.h"
   9 #include "registers.h"
  10
  11 static struct idxd_desc *__get_desc(struct idxd_wq *wq, int idx, int cpu)
  12 {
  13         struct idxd_desc *desc;
  14         struct idxd_device *idxd = wq->idxd;
  15
  16         desc = wq->descs[idx];
  17         memset(desc->hw, 0, sizeof(struct dsa_hw_desc));
  18         memset(desc->completion, 0, idxd->data->compl_size);
  19         desc->cpu = cpu;
  20
  21         if (device_pasid_enabled(idxd))
  22                 desc->hw->pasid = idxd->pasid;
  23
  24         /*
  25          * On host, MSIX vecotr 0 is used for misc interrupt. Therefore when we match
  26          * vector 1:1 to the WQ id, we need to add 1
  27          */
  28         if (!idxd->int_handles)
  29                 desc->hw->int_handle = wq->id + 1;
  30         else
  31                 desc->hw->int_handle = idxd->int_handles[wq->id];
  32
  33         return desc;
  34 }
  35
  36 struct idxd_desc *idxd_alloc_desc(struct idxd_wq *wq, enum idxd_op_type optype)
  37 {
  38         int cpu, idx;
  39         struct idxd_device *idxd = wq->idxd;
  40         DEFINE_SBQ_WAIT(wait);
  41         struct sbq_wait_state *ws;
  42         struct sbitmap_queue *sbq;
  43
  44         if (idxd->state != IDXD_DEV_ENABLED)
  45                 return ERR_PTR(-EIO);
  46
  47         sbq = &wq->sbq;
  48         idx = sbitmap_queue_get(sbq, &cpu);
  49         if (idx < 0) {
  50                 if (optype == IDXD_OP_NONBLOCK)
  51                         return ERR_PTR(-EAGAIN);
  52         } else {
  53                 return __get_desc(wq, idx, cpu);
  54         }
  55
  56         ws = &sbq->ws[0];
  57         for (;;) {
  58                 sbitmap_prepare_to_wait(sbq, ws, &wait, TASK_INTERRUPTIBLE);
  59                 if (signal_pending_state(TASK_INTERRUPTIBLE, current))
  60                         break;
  61                 idx = sbitmap_queue_get(sbq, &cpu);
  62                 if (idx >= 0)
  63                         break;
  64                 schedule();
  65         }
  66
  67         sbitmap_finish_wait(sbq, ws, &wait);
  68         if (idx < 0)
  69                 return ERR_PTR(-EAGAIN);
  70
  71         return __get_desc(wq, idx, cpu);
  72 }
  73
  74 void idxd_free_desc(struct idxd_wq *wq, struct idxd_desc *desc)
  75 {
  76         int cpu = desc->cpu;
  77
  78         desc->cpu = -1;
  79         sbitmap_queue_clear(&wq->sbq, desc->id, cpu);
  80 }
  81
  82 static struct idxd_desc *list_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
  83                                          struct idxd_desc *desc)
  84 {
  85         struct idxd_desc *d, *n;
  86
  87         lockdep_assert_held(&ie->list_lock);
  88         list_for_each_entry_safe(d, n, &ie->work_list, list) {
  89                 if (d == desc) {
  90                         list_del(&d->list);
  91                         return d;
  92                 }
  93         }
  94
  95         /*
  96          * At this point, the desc needs to be aborted is held by the completion
  97          * handler where it has taken it off the pending list but has not added to the
  98          * work list. It will be cleaned up by the interrupt handler when it sees the
  99          * IDXD_COMP_DESC_ABORT for completion status.
 100          */
 101         return NULL;
 102 }
 103
 104 static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
 105                              struct idxd_desc *desc)
 106 {
 107         struct idxd_desc *d, *t, *found = NULL;
 108         struct llist_node *head;
 109         LIST_HEAD(flist);
 110
 111         desc->completion->status = IDXD_COMP_DESC_ABORT;
 112         /*
 113          * Grab the list lock so it will block the irq thread handler. This allows the
 114          * abort code to locate the descriptor need to be aborted.
 115          */
 116         spin_lock(&ie->list_lock);
 117         head = llist_del_all(&ie->pending_llist);
 118         if (head) {
 119                 llist_for_each_entry_safe(d, t, head, llnode) {
 120                         if (d == desc) {
 121                                 found = desc;
 122                                 continue;
 123                         }
 124
 125                         if (d->completion->status)
 126                                 list_add_tail(&d->list, &flist);
 127                         else
 128                                 list_add_tail(&d->list, &ie->work_list);
 129                 }
 130         }
 131
 132         if (!found)
 133                 found = list_abort_desc(wq, ie, desc);
 134         spin_unlock(&ie->list_lock);
 135
 136         if (found)
 137                 complete_desc(found, IDXD_COMPLETE_ABORT);
 138
 139         /*
 140          * complete_desc() will return desc to allocator and the desc can be
 141          * acquired by a different process and the desc->list can be modified.
 142          * Delete desc from list so the list trasversing does not get corrupted
 143          * by the other process.
 144          */
 145         list_for_each_entry_safe(d, t, &flist, list) {
 146                 list_del_init(&d->list);
 147                 complete_desc(d, IDXD_COMPLETE_NORMAL);
 148         }
 149 }
 150
 151 int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 152 {
 153         struct idxd_device *idxd = wq->idxd;
 154         struct idxd_irq_entry *ie = NULL;
 155         void __iomem *portal;
 156         int rc;
 157
 158         if (idxd->state != IDXD_DEV_ENABLED) {
 159                 idxd_free_desc(wq, desc);
 160                 return -EIO;
 161         }
 162
 163         if (!percpu_ref_tryget_live(&wq->wq_active)) {
 164                 idxd_free_desc(wq, desc);
 165                 return -ENXIO;
 166         }
 167
 168         portal = idxd_wq_portal_addr(wq);
 169
 170         /*
 171          * The wmb() flushes writes to coherent DMA data before
 172          * possibly triggering a DMA read. The wmb() is necessary
 173          * even on UP because the recipient is a device.
 174          */
 175         wmb();
 176
 177         /*
 178          * Pending the descriptor to the lockless list for the irq_entry
 179          * that we designated the descriptor to.
 180          */
 181         if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
 182                 ie = &idxd->irq_entries[wq->id + 1];
 183                 llist_add(&desc->llnode, &ie->pending_llist);
 184         }
 185
 186         if (wq_dedicated(wq)) {
 187                 iosubmit_cmds512(portal, desc->hw, 1);
 188         } else {
 189                 /*
 190                  * It's not likely that we would receive queue full rejection
 191                  * since the descriptor allocation gates at wq size. If we
 192                  * receive a -EAGAIN, that means something went wrong such as the
 193                  * device is not accepting descriptor at all.
 194                  */
 195                 rc = enqcmds(portal, desc->hw);
 196                 if (rc < 0) {
 197                         percpu_ref_put(&wq->wq_active);
 198                         /* abort operation frees the descriptor */
 199                         if (ie)
 200                                 llist_abort_desc(wq, ie, desc);
 201                         else
 202                                 idxd_free_desc(wq, desc);
 203                         return rc;
 204                 }
 205         }
 206
 207         percpu_ref_put(&wq->wq_active);
 208         return 0;
 209 }