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
 110         desc->completion->status = IDXD_COMP_DESC_ABORT;
 111         /*
 112          * Grab the list lock so it will block the irq thread handler. This allows the
 113          * abort code to locate the descriptor need to be aborted.
 114          */
 115         spin_lock(&ie->list_lock);
 116         head = llist_del_all(&ie->pending_llist);
 117         if (head) {
 118                 llist_for_each_entry_safe(d, t, head, llnode) {
 119                         if (d == desc) {
 120                                 found = desc;
 121                                 continue;
 122                         }
 123                         list_add_tail(&desc->list, &ie->work_list);
 124                 }
 125         }
 126
 127         if (!found)
 128                 found = list_abort_desc(wq, ie, desc);
 129         spin_unlock(&ie->list_lock);
 130
 131         if (found)
 132                 complete_desc(found, IDXD_COMPLETE_ABORT);
 133 }
 134
 135 int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 136 {
 137         struct idxd_device *idxd = wq->idxd;
 138         struct idxd_irq_entry *ie = NULL;
 139         void __iomem *portal;
 140         int rc;
 141
 142         if (idxd->state != IDXD_DEV_ENABLED) {
 143                 idxd_free_desc(wq, desc);
 144                 return -EIO;
 145         }
 146
 147         if (!percpu_ref_tryget_live(&wq->wq_active)) {
 148                 idxd_free_desc(wq, desc);
 149                 return -ENXIO;
 150         }
 151
 152         portal = idxd_wq_portal_addr(wq);
 153
 154         /*
 155          * The wmb() flushes writes to coherent DMA data before
 156          * possibly triggering a DMA read. The wmb() is necessary
 157          * even on UP because the recipient is a device.
 158          */
 159         wmb();
 160
 161         /*
 162          * Pending the descriptor to the lockless list for the irq_entry
 163          * that we designated the descriptor to.
 164          */
 165         if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
 166                 ie = &idxd->irq_entries[wq->id + 1];
 167                 llist_add(&desc->llnode, &ie->pending_llist);
 168         }
 169
 170         if (wq_dedicated(wq)) {
 171                 iosubmit_cmds512(portal, desc->hw, 1);
 172         } else {
 173                 /*
 174                  * It's not likely that we would receive queue full rejection
 175                  * since the descriptor allocation gates at wq size. If we
 176                  * receive a -EAGAIN, that means something went wrong such as the
 177                  * device is not accepting descriptor at all.
 178                  */
 179                 rc = enqcmds(portal, desc->hw);
 180                 if (rc < 0) {
 181                         percpu_ref_put(&wq->wq_active);
 182                         /* abort operation frees the descriptor */
 183                         if (ie)
 184                                 llist_abort_desc(wq, ie, desc);
 185                         else
 186                                 idxd_free_desc(wq, desc);
 187                         return rc;
 188                 }
 189         }
 190
 191         percpu_ref_put(&wq->wq_active);
 192         return 0;
 193 }