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xen-netback: Factor queue-specific data into queue struct
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In preparation for multi-queue support in xen-netback, move the
queue-specific data from struct xenvif into struct xenvif_queue, and
update the rest of the code to use this.

Also adds loops over queues where appropriate, even though only one is
configured at this point, and uses alloc_netdev_mq() and the
corresponding multi-queue netif wake/start/stop functions in preparation
for multiple active queues.

Finally, implements a trivial queue selection function suitable for
ndo_select_queue, which simply returns 0 for a single queue and uses
skb_get_hash() to compute the queue index otherwise.

Signed-off-by: Andrew J. Bennieston <andrew.bennieston@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Wei Liu authored and David S. Miller committed Jun 4, 2014
1 parent a55d976 commit e9ce7cb
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Showing 4 changed files with 819 additions and 590 deletions.
102 changes: 69 additions & 33 deletions drivers/net/xen-netback/common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -99,22 +99,43 @@ struct xenvif_rx_meta {
*/
#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN

struct xenvif {
/* Unique identifier for this interface. */
domid_t domid;
unsigned int handle;
/* Queue name is interface name with "-qNNN" appended */
#define QUEUE_NAME_SIZE (IFNAMSIZ + 5)

/* Is this interface disabled? True when backend discovers
* frontend is rogue.
/* IRQ name is queue name with "-tx" or "-rx" appended */
#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)

struct xenvif;

struct xenvif_stats {
/* Stats fields to be updated per-queue.
* A subset of struct net_device_stats that contains only the
* fields that are updated in netback.c for each queue.
*/
bool disabled;
unsigned int rx_bytes;
unsigned int rx_packets;
unsigned int tx_bytes;
unsigned int tx_packets;

/* Additional stats used by xenvif */
unsigned long rx_gso_checksum_fixup;
unsigned long tx_zerocopy_sent;
unsigned long tx_zerocopy_success;
unsigned long tx_zerocopy_fail;
unsigned long tx_frag_overflow;
};

struct xenvif_queue { /* Per-queue data for xenvif */
unsigned int id; /* Queue ID, 0-based */
char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
struct xenvif *vif; /* Parent VIF */

/* 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 */
char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
struct xen_netif_tx_back_ring tx;
struct sk_buff_head tx_queue;
struct page *mmap_pages[MAX_PENDING_REQS];
Expand Down Expand Up @@ -150,7 +171,7 @@ struct xenvif {
/* 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 */
char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
struct xen_netif_rx_back_ring rx;
struct sk_buff_head rx_queue;
RING_IDX rx_last_skb_slots;
Expand All @@ -165,6 +186,22 @@ struct xenvif {
*/
struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];

/* 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 */
struct xenvif_stats stats;
};

struct xenvif {
/* Unique identifier for this interface. */
domid_t domid;
unsigned int handle;

u8 fe_dev_addr[6];

/* Frontend feature information. */
Expand All @@ -178,19 +215,13 @@ struct xenvif {
/* 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;
/* Is this interface disabled? True when backend discovers
* frontend is rogue.
*/
bool disabled;

/* Statistics */
unsigned long rx_gso_checksum_fixup;
unsigned long tx_zerocopy_sent;
unsigned long tx_zerocopy_success;
unsigned long tx_zerocopy_fail;
unsigned long tx_frag_overflow;
/* Queues */
struct xenvif_queue *queues;

/* Miscellaneous private stuff. */
struct net_device *dev;
Expand All @@ -205,7 +236,9 @@ struct xenvif *xenvif_alloc(struct device *parent,
domid_t domid,
unsigned int handle);

int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
int xenvif_init_queue(struct xenvif_queue *queue);

int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
unsigned long rx_ring_ref, unsigned int tx_evtchn,
unsigned int rx_evtchn);
void xenvif_disconnect(struct xenvif *vif);
Expand All @@ -216,44 +249,47 @@ void xenvif_xenbus_fini(void);

int xenvif_schedulable(struct xenvif *vif);

int xenvif_must_stop_queue(struct xenvif *vif);
int xenvif_must_stop_queue(struct xenvif_queue *queue);

int xenvif_queue_stopped(struct xenvif_queue *queue);
void xenvif_wake_queue(struct xenvif_queue *queue);

/* (Un)Map communication rings. */
void xenvif_unmap_frontend_rings(struct xenvif *vif);
int xenvif_map_frontend_rings(struct xenvif *vif,
void xenvif_unmap_frontend_rings(struct xenvif_queue *queue);
int xenvif_map_frontend_rings(struct xenvif_queue *queue,
grant_ref_t tx_ring_ref,
grant_ref_t rx_ring_ref);

/* Check for SKBs from frontend and schedule backend processing */
void xenvif_napi_schedule_or_enable_events(struct xenvif *vif);
void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue);

/* 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_tx_action(struct xenvif_queue *queue, int budget);

int xenvif_kthread_guest_rx(void *data);
void xenvif_kick_thread(struct xenvif *vif);
void xenvif_kick_thread(struct xenvif_queue *queue);

int xenvif_dealloc_kthread(void *data);

/* 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);
bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed);

void xenvif_stop_queue(struct xenvif *vif);
void xenvif_carrier_on(struct xenvif *vif);

/* Callback from stack when TX packet can be released */
void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);

/* Unmap a pending page and release it back to the guest */
void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx);
void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);

static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
{
return MAX_PENDING_REQS -
vif->pending_prod + vif->pending_cons;
queue->pending_prod + queue->pending_cons;
}

/* Callback from stack when TX packet can be released */
Expand Down
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