forked from Minki/linux
11b57f9025
The recent patch to improve guest receive side flow control (ca2f09f2) had a
slight flaw in the wait condition for the vif thread in that any remaining
skbs in the guest receive side netback internal queue would prevent the
thread from sleeping. An unresponsive frontend can lead to a permanently
non-empty internal queue and thus the thread will spin. In this case the
thread should really sleep until the frontend becomes responsive again.
This patch adds an extra flag to the vif which is set if the shared ring
is full and cleared when skbs are drained into the shared ring. Thus,
if the thread runs, finds the shared ring full and can make no progress the
flag remains set. If the flag remains set then the thread will sleep,
regardless of a non-empty queue, until the next event from the frontend.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
236 lines
7.3 KiB
C
236 lines
7.3 KiB
C
/*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License version 2
|
|
* as published by the Free Software Foundation; or, when distributed
|
|
* separately from the Linux kernel or incorporated into other
|
|
* software packages, subject to the following license:
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this source file (the "Software"), to deal in the Software without
|
|
* restriction, including without limitation the rights to use, copy, modify,
|
|
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
|
|
* and to permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
|
* IN THE SOFTWARE.
|
|
*/
|
|
|
|
#ifndef __XEN_NETBACK__COMMON_H__
|
|
#define __XEN_NETBACK__COMMON_H__
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/in.h>
|
|
#include <linux/io.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/etherdevice.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/sched.h>
|
|
|
|
#include <xen/interface/io/netif.h>
|
|
#include <xen/interface/grant_table.h>
|
|
#include <xen/grant_table.h>
|
|
#include <xen/xenbus.h>
|
|
|
|
typedef unsigned int pending_ring_idx_t;
|
|
#define INVALID_PENDING_RING_IDX (~0U)
|
|
|
|
/* For the head field in pending_tx_info: it is used to indicate
|
|
* whether this tx info is the head of one or more coalesced requests.
|
|
*
|
|
* When head != INVALID_PENDING_RING_IDX, it means the start of a new
|
|
* tx requests queue and the end of previous queue.
|
|
*
|
|
* An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
|
|
*
|
|
* ...|0 I I I|5 I|9 I I I|...
|
|
* -->|<-INUSE----------------
|
|
*
|
|
* After consuming the first slot(s) we have:
|
|
*
|
|
* ...|V V V V|5 I|9 I I I|...
|
|
* -----FREE->|<-INUSE--------
|
|
*
|
|
* where V stands for "valid pending ring index". Any number other
|
|
* than INVALID_PENDING_RING_IDX is OK. These entries are considered
|
|
* free and can contain any number other than
|
|
* INVALID_PENDING_RING_IDX. In practice we use 0.
|
|
*
|
|
* The in use non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the
|
|
* above example) number is the index into pending_tx_info and
|
|
* mmap_pages arrays.
|
|
*/
|
|
struct pending_tx_info {
|
|
struct xen_netif_tx_request req; /* coalesced tx request */
|
|
pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
|
|
* if it is head of one or more tx
|
|
* reqs
|
|
*/
|
|
};
|
|
|
|
#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
|
|
#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
|
|
|
|
struct xenvif_rx_meta {
|
|
int id;
|
|
int size;
|
|
int gso_type;
|
|
int gso_size;
|
|
};
|
|
|
|
#define GSO_BIT(type) \
|
|
(1 << XEN_NETIF_GSO_TYPE_ ## type)
|
|
|
|
/* Discriminate from any valid pending_idx value. */
|
|
#define INVALID_PENDING_IDX 0xFFFF
|
|
|
|
#define MAX_BUFFER_OFFSET PAGE_SIZE
|
|
|
|
#define MAX_PENDING_REQS 256
|
|
|
|
/* It's possible for an skb to have a maximal number of frags
|
|
* but still be less than MAX_BUFFER_OFFSET in size. Thus the
|
|
* worst-case number of copy operations is MAX_SKB_FRAGS per
|
|
* ring slot.
|
|
*/
|
|
#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
|
|
|
|
struct xenvif {
|
|
/* Unique identifier for this interface. */
|
|
domid_t domid;
|
|
unsigned int handle;
|
|
|
|
/* Use NAPI for guest TX */
|
|
struct napi_struct napi;
|
|
/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
|
|
unsigned int tx_irq;
|
|
/* Only used when feature-split-event-channels = 1 */
|
|
char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
|
|
struct xen_netif_tx_back_ring tx;
|
|
struct sk_buff_head tx_queue;
|
|
struct page *mmap_pages[MAX_PENDING_REQS];
|
|
pending_ring_idx_t pending_prod;
|
|
pending_ring_idx_t pending_cons;
|
|
u16 pending_ring[MAX_PENDING_REQS];
|
|
struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
|
|
|
|
/* Coalescing tx requests before copying makes number of grant
|
|
* copy ops greater or equal to number of slots required. In
|
|
* worst case a tx request consumes 2 gnttab_copy.
|
|
*/
|
|
struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
|
|
|
|
|
|
/* Use kthread for guest RX */
|
|
struct task_struct *task;
|
|
wait_queue_head_t wq;
|
|
/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
|
|
unsigned int rx_irq;
|
|
/* Only used when feature-split-event-channels = 1 */
|
|
char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
|
|
struct xen_netif_rx_back_ring rx;
|
|
struct sk_buff_head rx_queue;
|
|
bool rx_queue_stopped;
|
|
/* Set when the RX interrupt is triggered by the frontend.
|
|
* The worker thread may need to wake the queue.
|
|
*/
|
|
bool rx_event;
|
|
|
|
/* This array is allocated seperately as it is large */
|
|
struct gnttab_copy *grant_copy_op;
|
|
|
|
/* We create one meta structure per ring request we consume, so
|
|
* the maximum number is the same as the ring size.
|
|
*/
|
|
struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
|
|
|
|
u8 fe_dev_addr[6];
|
|
|
|
/* Frontend feature information. */
|
|
int gso_mask;
|
|
int gso_prefix_mask;
|
|
|
|
u8 can_sg:1;
|
|
u8 ip_csum:1;
|
|
u8 ipv6_csum:1;
|
|
|
|
/* Internal feature information. */
|
|
u8 can_queue:1; /* can queue packets for receiver? */
|
|
|
|
/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
|
|
unsigned long credit_bytes;
|
|
unsigned long credit_usec;
|
|
unsigned long remaining_credit;
|
|
struct timer_list credit_timeout;
|
|
u64 credit_window_start;
|
|
|
|
/* Statistics */
|
|
unsigned long rx_gso_checksum_fixup;
|
|
|
|
/* Miscellaneous private stuff. */
|
|
struct net_device *dev;
|
|
};
|
|
|
|
static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
|
|
{
|
|
return to_xenbus_device(vif->dev->dev.parent);
|
|
}
|
|
|
|
struct xenvif *xenvif_alloc(struct device *parent,
|
|
domid_t domid,
|
|
unsigned int handle);
|
|
|
|
int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
|
|
unsigned long rx_ring_ref, unsigned int tx_evtchn,
|
|
unsigned int rx_evtchn);
|
|
void xenvif_disconnect(struct xenvif *vif);
|
|
void xenvif_free(struct xenvif *vif);
|
|
|
|
int xenvif_xenbus_init(void);
|
|
void xenvif_xenbus_fini(void);
|
|
|
|
int xenvif_schedulable(struct xenvif *vif);
|
|
|
|
int xenvif_must_stop_queue(struct xenvif *vif);
|
|
|
|
/* (Un)Map communication rings. */
|
|
void xenvif_unmap_frontend_rings(struct xenvif *vif);
|
|
int xenvif_map_frontend_rings(struct xenvif *vif,
|
|
grant_ref_t tx_ring_ref,
|
|
grant_ref_t rx_ring_ref);
|
|
|
|
/* Check for SKBs from frontend and schedule backend processing */
|
|
void xenvif_check_rx_xenvif(struct xenvif *vif);
|
|
|
|
/* Prevent the device from generating any further traffic. */
|
|
void xenvif_carrier_off(struct xenvif *vif);
|
|
|
|
int xenvif_tx_action(struct xenvif *vif, int budget);
|
|
|
|
int xenvif_kthread(void *data);
|
|
void xenvif_kick_thread(struct xenvif *vif);
|
|
|
|
/* Determine whether the needed number of slots (req) are available,
|
|
* and set req_event if not.
|
|
*/
|
|
bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
|
|
|
|
void xenvif_stop_queue(struct xenvif *vif);
|
|
|
|
extern bool separate_tx_rx_irq;
|
|
|
|
#endif /* __XEN_NETBACK__COMMON_H__ */
|