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1// SPDX-License-Identifier: GPL-2.0-only2// SPDX-FileCopyrightText: Copyright Red Hat3 4#include <linux/bitfield.h>5#include <linux/cleanup.h>6#include <linux/mutex.h>7#include <linux/pci.h>8#include <linux/slab.h>9#include <linux/spinlock.h>10#include <linux/xarray.h>11#include "ice_adapter.h"12 13static DEFINE_XARRAY(ice_adapters);14static DEFINE_MUTEX(ice_adapters_mutex);15 16/* PCI bus number is 8 bits. Slot is 5 bits. Domain can have the rest. */17#define INDEX_FIELD_DOMAIN GENMASK(BITS_PER_LONG - 1, 13)18#define INDEX_FIELD_BUS GENMASK(12, 5)19#define INDEX_FIELD_SLOT GENMASK(4, 0)20 21static unsigned long ice_adapter_index(const struct pci_dev *pdev)22{23 unsigned int domain = pci_domain_nr(pdev->bus);24 25 WARN_ON(domain > FIELD_MAX(INDEX_FIELD_DOMAIN));26 27 return FIELD_PREP(INDEX_FIELD_DOMAIN, domain) |28 FIELD_PREP(INDEX_FIELD_BUS, pdev->bus->number) |29 FIELD_PREP(INDEX_FIELD_SLOT, PCI_SLOT(pdev->devfn));30}31 32static struct ice_adapter *ice_adapter_new(void)33{34 struct ice_adapter *adapter;35 36 adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);37 if (!adapter)38 return NULL;39 40 spin_lock_init(&adapter->ptp_gltsyn_time_lock);41 refcount_set(&adapter->refcount, 1);42 43 return adapter;44}45 46static void ice_adapter_free(struct ice_adapter *adapter)47{48 kfree(adapter);49}50 51/**52 * ice_adapter_get - Get a shared ice_adapter structure.53 * @pdev: Pointer to the pci_dev whose driver is getting the ice_adapter.54 *55 * Gets a pointer to a shared ice_adapter structure. Physical functions (PFs)56 * of the same multi-function PCI device share one ice_adapter structure.57 * The ice_adapter is reference-counted. The PF driver must use ice_adapter_put58 * to release its reference.59 *60 * Context: Process, may sleep.61 * Return: Pointer to ice_adapter on success.62 * ERR_PTR() on error. -ENOMEM is the only possible error.63 */64struct ice_adapter *ice_adapter_get(const struct pci_dev *pdev)65{66 unsigned long index = ice_adapter_index(pdev);67 struct ice_adapter *adapter;68 int err;69 70 scoped_guard(mutex, &ice_adapters_mutex) {71 err = xa_insert(&ice_adapters, index, NULL, GFP_KERNEL);72 if (err == -EBUSY) {73 adapter = xa_load(&ice_adapters, index);74 refcount_inc(&adapter->refcount);75 return adapter;76 }77 if (err)78 return ERR_PTR(err);79 80 adapter = ice_adapter_new();81 if (!adapter)82 return ERR_PTR(-ENOMEM);83 xa_store(&ice_adapters, index, adapter, GFP_KERNEL);84 }85 return adapter;86}87 88/**89 * ice_adapter_put - Release a reference to the shared ice_adapter structure.90 * @pdev: Pointer to the pci_dev whose driver is releasing the ice_adapter.91 *92 * Releases the reference to ice_adapter previously obtained with93 * ice_adapter_get.94 *95 * Context: Process, may sleep.96 */97void ice_adapter_put(const struct pci_dev *pdev)98{99 unsigned long index = ice_adapter_index(pdev);100 struct ice_adapter *adapter;101 102 scoped_guard(mutex, &ice_adapters_mutex) {103 adapter = xa_load(&ice_adapters, index);104 if (WARN_ON(!adapter))105 return;106 if (!refcount_dec_and_test(&adapter->refcount))107 return;108 109 WARN_ON(xa_erase(&ice_adapters, index) != adapter);110 }111 ice_adapter_free(adapter);112}113