linux/arch/um/drivers/vector_kern.h
Anton Ivanov 612a8c8e0b um: vector: Replace locks guarding queue depth with atomics
UML vector drivers use ring buffer structures which map
preallocated skbs onto mmsg vectors for use with sendmmsg
and recvmmsg. They are designed around a single consumer,
single producer pattern allowing simultaneous enqueue and
dequeue.

Lock debugging with preemption showed possible races when
locking the queue depth. This patch addresses this by
removing extra locks, adding barriers and making queue
depth inc/dec and access atomic.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2024-09-12 19:56:05 +02:00

140 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2002 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#ifndef __UM_VECTOR_KERN_H
#define __UM_VECTOR_KERN_H
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/list.h>
#include <linux/ctype.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <asm/atomic.h>
#include "vector_user.h"
/* Queue structure specially adapted for multiple enqueue/dequeue
* in a mmsgrecv/mmsgsend context
*/
/* Dequeue method */
#define QUEUE_SENDMSG 0
#define QUEUE_SENDMMSG 1
#define VECTOR_RX 1
#define VECTOR_TX (1 << 1)
#define VECTOR_BPF (1 << 2)
#define VECTOR_QDISC_BYPASS (1 << 3)
#define VECTOR_BPF_FLASH (1 << 4)
#define ETH_MAX_PACKET 1500
#define ETH_HEADER_OTHER 32 /* just in case someone decides to go mad on QnQ */
#define MAX_FILTER_PROG (2 << 16)
struct vector_queue {
struct mmsghdr *mmsg_vector;
void **skbuff_vector;
/* backlink to device which owns us */
struct net_device *dev;
spinlock_t head_lock;
spinlock_t tail_lock;
atomic_t queue_depth;
int head, tail, max_depth, max_iov_frags;
short options;
};
struct vector_estats {
uint64_t rx_queue_max;
uint64_t rx_queue_running_average;
uint64_t tx_queue_max;
uint64_t tx_queue_running_average;
uint64_t rx_encaps_errors;
uint64_t tx_timeout_count;
uint64_t tx_restart_queue;
uint64_t tx_kicks;
uint64_t tx_flow_control_xon;
uint64_t tx_flow_control_xoff;
uint64_t rx_csum_offload_good;
uint64_t rx_csum_offload_errors;
uint64_t sg_ok;
uint64_t sg_linearized;
};
#define VERIFY_HEADER_NOK -1
#define VERIFY_HEADER_OK 0
#define VERIFY_CSUM_OK 1
struct vector_private {
struct list_head list;
struct net_device *dev;
struct napi_struct napi ____cacheline_aligned;
int unit;
/* Timeout timer in TX */
struct timer_list tl;
/* Scheduled "remove device" work */
struct work_struct reset_tx;
struct vector_fds *fds;
struct vector_queue *rx_queue;
struct vector_queue *tx_queue;
int rx_irq;
int tx_irq;
struct arglist *parsed;
void *transport_data; /* transport specific params if needed */
int max_packet;
int req_size; /* different from max packet - used for TSO */
int headroom;
int options;
/* remote address if any - some transports will leave this as null */
int header_size;
int rx_header_size;
int coalesce;
void *header_rxbuffer;
void *header_txbuffer;
int (*form_header)(uint8_t *header,
struct sk_buff *skb, struct vector_private *vp);
int (*verify_header)(uint8_t *header,
struct sk_buff *skb, struct vector_private *vp);
spinlock_t stats_lock;
bool rexmit_scheduled;
bool opened;
bool in_write_poll;
bool in_error;
/* guest allowed to use ethtool flash to load bpf */
bool bpf_via_flash;
/* ethtool stats */
struct vector_estats estats;
struct sock_fprog *bpf;
char user[];
};
extern int build_transport_data(struct vector_private *vp);
#endif