linux/drivers/dma/idxd/submit.c

// 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 *idxd_alloc_desc(struct idxd_wq *wq, enum idxd_op_type optype)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

void idxd_free_desc(struct idxd_wq *wq, struct idxd_desc *desc)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

static struct idxd_desc *list_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
					 struct idxd_desc *desc)
{ … }

static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
			     struct idxd_desc *desc)
{ … }

/*
 * ENQCMDS typically fail when the WQ is inactive or busy. On host submission, the driver
 * has better control of number of descriptors being submitted to a shared wq by limiting
 * the number of driver allocated descriptors to the wq size. However, when the swq is
 * exported to a guest kernel, it may be shared with multiple guest kernels. This means
 * the likelihood of getting busy returned on the swq when submitting goes significantly up.
 * Having a tunable retry mechanism allows the driver to keep trying for a bit before giving
 * up. The sysfs knob can be tuned by the system administrator.
 */
int idxd_enqcmds(struct idxd_wq *wq, void __iomem *portal, const void *desc)
{ … }

int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
{ … }
EXPORT_SYMBOL_NS_GPL(…);