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// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <uapi/linux/idxd.h>
#include "idxd.h"
#include "registers.h"
static struct idxd_desc *__get_desc(struct idxd_wq *wq, int idx, int cpu)
{
struct idxd_desc *desc;
struct idxd_device *idxd = wq->idxd;
desc = wq->descs[idx];
memset(desc->hw, 0, sizeof(struct dsa_hw_desc));
memset(desc->completion, 0, idxd->data->compl_size);
desc->cpu = cpu;
if (device_pasid_enabled(idxd))
desc->hw->pasid = idxd->pasid;
/*
* Descriptor completion vectors are 1...N for MSIX. We will round
* robin through the N vectors.
*/
wq->vec_ptr = desc->vector = (wq->vec_ptr % idxd->num_wq_irqs) + 1;
if (!idxd->int_handles) {
desc->hw->int_handle = wq->vec_ptr;
} else {
/*
* int_handles are only for descriptor completion. However for device
* MSIX enumeration, vec 0 is used for misc interrupts. Therefore even
* though we are rotating through 1...N for descriptor interrupts, we
* need to acqurie the int_handles from 0..N-1.
*/
desc->hw->int_handle = idxd->int_handles[desc->vector - 1];
}
return desc;
}
struct idxd_desc *idxd_alloc_desc(struct idxd_wq *wq, enum idxd_op_type optype)
{
int cpu, idx;
struct idxd_device *idxd = wq->idxd;
DEFINE_SBQ_WAIT(wait);
struct sbq_wait_state *ws;
struct sbitmap_queue *sbq;
if (idxd->state != IDXD_DEV_ENABLED)
return ERR_PTR(-EIO);
sbq = &wq->sbq;
idx = sbitmap_queue_get(sbq, &cpu);
if (idx < 0) {
if (optype == IDXD_OP_NONBLOCK)
return ERR_PTR(-EAGAIN);
} else {
return __get_desc(wq, idx, cpu);
}
ws = &sbq->ws[0];
for (;;) {
sbitmap_prepare_to_wait(sbq, ws, &wait, TASK_INTERRUPTIBLE);
if (signal_pending_state(TASK_INTERRUPTIBLE, current))
break;
idx = sbitmap_queue_get(sbq, &cpu);
if (idx > 0)
break;
schedule();
}
sbitmap_finish_wait(sbq, ws, &wait);
if (idx < 0)
return ERR_PTR(-EAGAIN);
return __get_desc(wq, idx, cpu);
}
void idxd_free_desc(struct idxd_wq *wq, struct idxd_desc *desc)
{
int cpu = desc->cpu;
desc->cpu = -1;
sbitmap_queue_clear(&wq->sbq, desc->id, cpu);
}
static struct idxd_desc *list_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
struct idxd_desc *desc)
{
struct idxd_desc *d, *n;
lockdep_assert_held(&ie->list_lock);
list_for_each_entry_safe(d, n, &ie->work_list, list) {
if (d == desc) {
list_del(&d->list);
return d;
}
}
/*
* At this point, the desc needs to be aborted is held by the completion
* handler where it has taken it off the pending list but has not added to the
* work list. It will be cleaned up by the interrupt handler when it sees the
* IDXD_COMP_DESC_ABORT for completion status.
*/
return NULL;
}
static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
struct idxd_desc *desc)
{
struct idxd_desc *d, *t, *found = NULL;
struct llist_node *head;
unsigned long flags;
desc->completion->status = IDXD_COMP_DESC_ABORT;
/*
* Grab the list lock so it will block the irq thread handler. This allows the
* abort code to locate the descriptor need to be aborted.
*/
spin_lock_irqsave(&ie->list_lock, flags);
head = llist_del_all(&ie->pending_llist);
if (head) {
llist_for_each_entry_safe(d, t, head, llnode) {
if (d == desc) {
found = desc;
continue;
}
list_add_tail(&desc->list, &ie->work_list);
}
}
if (!found)
found = list_abort_desc(wq, ie, desc);
spin_unlock_irqrestore(&ie->list_lock, flags);
if (found)
complete_desc(found, IDXD_COMPLETE_ABORT);
}
int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
{
struct idxd_device *idxd = wq->idxd;
struct idxd_irq_entry *ie = NULL;
void __iomem *portal;
int rc;
if (idxd->state != IDXD_DEV_ENABLED)
return -EIO;
if (!percpu_ref_tryget_live(&wq->wq_active))
return -ENXIO;
portal = wq->portal;
/*
* The wmb() flushes writes to coherent DMA data before
* possibly triggering a DMA read. The wmb() is necessary
* even on UP because the recipient is a device.
*/
wmb();
/*
* Pending the descriptor to the lockless list for the irq_entry
* that we designated the descriptor to.
*/
if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
ie = &idxd->irq_entries[desc->vector];
llist_add(&desc->llnode, &ie->pending_llist);
}
if (wq_dedicated(wq)) {
iosubmit_cmds512(portal, desc->hw, 1);
} else {
/*
* It's not likely that we would receive queue full rejection
* since the descriptor allocation gates at wq size. If we
* receive a -EAGAIN, that means something went wrong such as the
* device is not accepting descriptor at all.
*/
rc = enqcmds(portal, desc->hw);
if (rc < 0) {
if (ie)
llist_abort_desc(wq, ie, desc);
return rc;
}
}
percpu_ref_put(&wq->wq_active);
return 0;
}
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