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![Wei Liu](/assets/img/avatar_default.png)
Reference count the number of packets in host stack, so that we don't stop the deallocation thread too early. If not, we can end up with xenvif_free permanently waiting for deallocation thread to unmap grefs. Reported-by: Thomas Leonard <talex5@gmail.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
337 lines
11 KiB
C
337 lines
11 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef __XEN_NETBACK__COMMON_H__
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#define __XEN_NETBACK__COMMON_H__
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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#include <linux/io.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include <xen/interface/io/netif.h>
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#include <xen/interface/grant_table.h>
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#include <xen/grant_table.h>
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#include <xen/xenbus.h>
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#include <linux/debugfs.h>
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typedef unsigned int pending_ring_idx_t;
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#define INVALID_PENDING_RING_IDX (~0U)
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struct pending_tx_info {
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struct xen_netif_tx_request req; /* tx request */
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/* Callback data for released SKBs. The callback is always
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* xenvif_zerocopy_callback, desc contains the pending_idx, which is
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* also an index in pending_tx_info array. It is initialized in
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* xenvif_alloc and it never changes.
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* skb_shinfo(skb)->destructor_arg points to the first mapped slot's
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* callback_struct in this array of struct pending_tx_info's, then ctx
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* to the next, or NULL if there is no more slot for this skb.
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* ubuf_to_vif is a helper which finds the struct xenvif from a pointer
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* to this field.
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*/
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struct ubuf_info callback_struct;
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};
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#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
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#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
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struct xenvif_rx_meta {
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int id;
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int size;
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int gso_type;
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int gso_size;
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};
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#define GSO_BIT(type) \
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(1 << XEN_NETIF_GSO_TYPE_ ## type)
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/* Discriminate from any valid pending_idx value. */
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#define INVALID_PENDING_IDX 0xFFFF
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#define MAX_BUFFER_OFFSET PAGE_SIZE
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#define MAX_PENDING_REQS XEN_NETIF_TX_RING_SIZE
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/* It's possible for an skb to have a maximal number of frags
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* but still be less than MAX_BUFFER_OFFSET in size. Thus the
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* worst-case number of copy operations is MAX_SKB_FRAGS per
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* ring slot.
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*/
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#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
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#define NETBACK_INVALID_HANDLE -1
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/* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
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* the maximum slots a valid packet can use. Now this value is defined
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* to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
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* all backend.
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*/
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#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
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/* Queue name is interface name with "-qNNN" appended */
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#define QUEUE_NAME_SIZE (IFNAMSIZ + 5)
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/* IRQ name is queue name with "-tx" or "-rx" appended */
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#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
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struct xenvif;
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struct xenvif_stats {
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/* Stats fields to be updated per-queue.
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* A subset of struct net_device_stats that contains only the
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* fields that are updated in netback.c for each queue.
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*/
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unsigned int rx_bytes;
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unsigned int rx_packets;
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unsigned int tx_bytes;
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unsigned int tx_packets;
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/* Additional stats used by xenvif */
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unsigned long rx_gso_checksum_fixup;
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unsigned long tx_zerocopy_sent;
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unsigned long tx_zerocopy_success;
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unsigned long tx_zerocopy_fail;
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unsigned long tx_frag_overflow;
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};
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struct xenvif_queue { /* Per-queue data for xenvif */
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unsigned int id; /* Queue ID, 0-based */
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char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
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struct xenvif *vif; /* Parent VIF */
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/* Use NAPI for guest TX */
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struct napi_struct napi;
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/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
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unsigned int tx_irq;
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/* Only used when feature-split-event-channels = 1 */
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char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
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struct xen_netif_tx_back_ring tx;
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struct sk_buff_head tx_queue;
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struct page *mmap_pages[MAX_PENDING_REQS];
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pending_ring_idx_t pending_prod;
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pending_ring_idx_t pending_cons;
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u16 pending_ring[MAX_PENDING_REQS];
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struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
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grant_handle_t grant_tx_handle[MAX_PENDING_REQS];
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struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
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struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
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struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
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/* passed to gnttab_[un]map_refs with pages under (un)mapping */
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struct page *pages_to_map[MAX_PENDING_REQS];
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struct page *pages_to_unmap[MAX_PENDING_REQS];
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/* This prevents zerocopy callbacks to race over dealloc_ring */
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spinlock_t callback_lock;
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/* This prevents dealloc thread and NAPI instance to race over response
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* creation and pending_ring in xenvif_idx_release. In xenvif_tx_err
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* it only protect response creation
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*/
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spinlock_t response_lock;
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pending_ring_idx_t dealloc_prod;
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pending_ring_idx_t dealloc_cons;
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u16 dealloc_ring[MAX_PENDING_REQS];
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struct task_struct *dealloc_task;
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wait_queue_head_t dealloc_wq;
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atomic_t inflight_packets;
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/* Use kthread for guest RX */
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struct task_struct *task;
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wait_queue_head_t wq;
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/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
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unsigned int rx_irq;
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/* Only used when feature-split-event-channels = 1 */
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char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
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struct xen_netif_rx_back_ring rx;
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struct sk_buff_head rx_queue;
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RING_IDX rx_last_skb_slots;
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unsigned long status;
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struct timer_list rx_stalled;
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struct gnttab_copy grant_copy_op[MAX_GRANT_COPY_OPS];
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/* We create one meta structure per ring request we consume, so
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* the maximum number is the same as the ring size.
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*/
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struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
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/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
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unsigned long credit_bytes;
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unsigned long credit_usec;
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unsigned long remaining_credit;
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struct timer_list credit_timeout;
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u64 credit_window_start;
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/* Statistics */
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struct xenvif_stats stats;
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};
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enum state_bit_shift {
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/* This bit marks that the vif is connected */
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VIF_STATUS_CONNECTED,
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/* This bit signals the RX thread that queuing was stopped (in
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* start_xmit), and either the timer fired or an RX interrupt came
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*/
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QUEUE_STATUS_RX_PURGE_EVENT,
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/* This bit tells the interrupt handler that this queue was the reason
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* for the carrier off, so it should kick the thread. Only queues which
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* brought it down can turn on the carrier.
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*/
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QUEUE_STATUS_RX_STALLED
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};
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struct xenvif {
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/* Unique identifier for this interface. */
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domid_t domid;
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unsigned int handle;
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u8 fe_dev_addr[6];
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/* Frontend feature information. */
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int gso_mask;
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int gso_prefix_mask;
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u8 can_sg:1;
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u8 ip_csum:1;
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u8 ipv6_csum:1;
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/* Internal feature information. */
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u8 can_queue:1; /* can queue packets for receiver? */
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/* Is this interface disabled? True when backend discovers
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* frontend is rogue.
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*/
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bool disabled;
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unsigned long status;
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/* Queues */
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struct xenvif_queue *queues;
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unsigned int num_queues; /* active queues, resource allocated */
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#ifdef CONFIG_DEBUG_FS
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struct dentry *xenvif_dbg_root;
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#endif
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/* Miscellaneous private stuff. */
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struct net_device *dev;
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};
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static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
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{
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return to_xenbus_device(vif->dev->dev.parent);
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}
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struct xenvif *xenvif_alloc(struct device *parent,
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domid_t domid,
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unsigned int handle);
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int xenvif_init_queue(struct xenvif_queue *queue);
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void xenvif_deinit_queue(struct xenvif_queue *queue);
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int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
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unsigned long rx_ring_ref, unsigned int tx_evtchn,
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unsigned int rx_evtchn);
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void xenvif_disconnect(struct xenvif *vif);
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void xenvif_free(struct xenvif *vif);
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int xenvif_xenbus_init(void);
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void xenvif_xenbus_fini(void);
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int xenvif_schedulable(struct xenvif *vif);
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int xenvif_must_stop_queue(struct xenvif_queue *queue);
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int xenvif_queue_stopped(struct xenvif_queue *queue);
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void xenvif_wake_queue(struct xenvif_queue *queue);
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/* (Un)Map communication rings. */
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void xenvif_unmap_frontend_rings(struct xenvif_queue *queue);
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int xenvif_map_frontend_rings(struct xenvif_queue *queue,
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grant_ref_t tx_ring_ref,
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grant_ref_t rx_ring_ref);
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/* Check for SKBs from frontend and schedule backend processing */
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void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue);
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/* Prevent the device from generating any further traffic. */
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void xenvif_carrier_off(struct xenvif *vif);
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int xenvif_tx_action(struct xenvif_queue *queue, int budget);
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int xenvif_kthread_guest_rx(void *data);
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void xenvif_kick_thread(struct xenvif_queue *queue);
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int xenvif_dealloc_kthread(void *data);
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/* Determine whether the needed number of slots (req) are available,
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* and set req_event if not.
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*/
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bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed);
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void xenvif_carrier_on(struct xenvif *vif);
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/* Callback from stack when TX packet can be released */
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void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
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/* Unmap a pending page and release it back to the guest */
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void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
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static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
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{
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return MAX_PENDING_REQS -
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queue->pending_prod + queue->pending_cons;
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}
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/* Callback from stack when TX packet can be released */
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void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
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irqreturn_t xenvif_interrupt(int irq, void *dev_id);
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extern bool separate_tx_rx_irq;
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extern unsigned int rx_drain_timeout_msecs;
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extern unsigned int rx_drain_timeout_jiffies;
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extern unsigned int xenvif_max_queues;
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#ifdef CONFIG_DEBUG_FS
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extern struct dentry *xen_netback_dbg_root;
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#endif
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void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
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struct sk_buff *skb);
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void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue);
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#endif /* __XEN_NETBACK__COMMON_H__ */
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