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xen-netback: Introduce TX grant mapping

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This patch introduces grant mapping on netback TX path. It replaces grant copy
operations, ditching grant copy coalescing along the way. Another solution for
copy coalescing is introduced in "xen-netback: Handle guests with too many
frags", older guests and Windows can broke before that patch applies.
There is a callback (xenvif_zerocopy_callback) from core stack to release the
slots back to the guests when kfree_skb or skb_orphan_frags called. It feeds a
separate dealloc thread, as scheduling NAPI instance from there is inefficient,
therefore we can't do dealloc from the instance.

Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Zoltan Kiss 2014-03-06 21:48:26 +00:00 committed by David S. Miller
parent 3e2234b314
commit f53c3fe8da
3 changed files with 370 additions and 164 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/net/xen-netback/common.h
View File

@ -79,6 +79,17 @@ struct pending_tx_info {
* if it is head of one or more tx
* reqs
*/
/* Callback data for released SKBs. The callback is always
* xenvif_zerocopy_callback, desc contains the pending_idx, which is
* also an index in pending_tx_info array. It is initialized in
* xenvif_alloc and it never changes.
* skb_shinfo(skb)->destructor_arg points to the first mapped slot's
* callback_struct in this array of struct pending_tx_info's, then ctx
* to the next, or NULL if there is no more slot for this skb.
* ubuf_to_vif is a helper which finds the struct xenvif from a pointer
* to this field.
*/
struct ubuf_info callback_struct;
};
#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
@ -135,13 +146,31 @@ struct xenvif {
pending_ring_idx_t pending_cons;
u16 pending_ring[MAX_PENDING_REQS];
struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
grant_handle_t grant_tx_handle[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];
struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
/* passed to gnttab_[un]map_refs with pages under (un)mapping */
struct page *pages_to_map[MAX_PENDING_REQS];
struct page *pages_to_unmap[MAX_PENDING_REQS];
/* This prevents zerocopy callbacks to race over dealloc_ring */
spinlock_t callback_lock;
/* This prevents dealloc thread and NAPI instance to race over response
* creation and pending_ring in xenvif_idx_release. In xenvif_tx_err
* it only protect response creation
*/
spinlock_t response_lock;
pending_ring_idx_t dealloc_prod;
pending_ring_idx_t dealloc_cons;
u16 dealloc_ring[MAX_PENDING_REQS];
struct task_struct *dealloc_task;
wait_queue_head_t dealloc_wq;
/* Use kthread for guest RX */
struct task_struct *task;
@ -228,6 +257,8 @@ int xenvif_tx_action(struct xenvif *vif, int budget);
int xenvif_kthread_guest_rx(void *data);
void xenvif_kick_thread(struct xenvif *vif);
int xenvif_dealloc_kthread(void *data);
/* Determine whether the needed number of slots (req) are available,
* and set req_event if not.
*/
@ -235,6 +266,12 @@ bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
void xenvif_stop_queue(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);
static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
{
return MAX_PENDING_REQS -

65
drivers/net/xen-netback/interface.c
View File

@ -38,6 +38,7 @@
#include <xen/events.h>
#include <asm/xen/hypercall.h>
#include <xen/balloon.h>
#define XENVIF_QUEUE_LENGTH 32
#define XENVIF_NAPI_WEIGHT 64
@ -87,7 +88,8 @@ static int xenvif_poll(struct napi_struct *napi, int budget)
local_irq_save(flags);
RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
if (!more_to_do)
if (!(more_to_do &&
xenvif_tx_pending_slots_available(vif)))
__napi_complete(napi);
local_irq_restore(flags);
@ -121,7 +123,9 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
BUG_ON(skb->dev != dev);
/* Drop the packet if vif is not ready */
if (vif->task == NULL || !xenvif_schedulable(vif))
if (vif->task == NULL ||
vif->dealloc_task == NULL ||
!xenvif_schedulable(vif))
goto drop;
/* At best we'll need one slot for the header and one for each
@ -343,8 +347,26 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
vif->pending_prod = MAX_PENDING_REQS;
for (i = 0; i < MAX_PENDING_REQS; i++)
vif->pending_ring[i] = i;
for (i = 0; i < MAX_PENDING_REQS; i++)
vif->mmap_pages[i] = NULL;
spin_lock_init(&vif->callback_lock);
spin_lock_init(&vif->response_lock);
/* If ballooning is disabled, this will consume real memory, so you
* better enable it. The long term solution would be to use just a
* bunch of valid page descriptors, without dependency on ballooning
*/
err = alloc_xenballooned_pages(MAX_PENDING_REQS,
vif->mmap_pages,
false);
if (err) {
netdev_err(dev, "Could not reserve mmap_pages\n");
return ERR_PTR(-ENOMEM);
}
for (i = 0; i < MAX_PENDING_REQS; i++) {
vif->pending_tx_info[i].callback_struct = (struct ubuf_info)
{ .callback = xenvif_zerocopy_callback,
.ctx = NULL,
.desc = i };
vif->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
}
/*
* Initialise a dummy MAC address. We choose the numerically
@ -382,12 +404,14 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
BUG_ON(vif->tx_irq);
BUG_ON(vif->task);
BUG_ON(vif->dealloc_task);
err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
if (err < 0)
goto err;
init_waitqueue_head(&vif->wq);
init_waitqueue_head(&vif->dealloc_wq);
if (tx_evtchn == rx_evtchn) {
/* feature-split-event-channels == 0 */
@ -431,6 +455,16 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
vif->task = task;
task = kthread_create(xenvif_dealloc_kthread,
(void *)vif, "%s-dealloc", vif->dev->name);
if (IS_ERR(task)) {
pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
err = PTR_ERR(task);
goto err_rx_unbind;
}
vif->dealloc_task = task;
rtnl_lock();
if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
dev_set_mtu(vif->dev, ETH_DATA_LEN);
@ -441,6 +475,7 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
rtnl_unlock();
wake_up_process(vif->task);
wake_up_process(vif->dealloc_task);
return 0;
@ -478,6 +513,11 @@ void xenvif_disconnect(struct xenvif *vif)
vif->task = NULL;
}
if (vif->dealloc_task) {
kthread_stop(vif->dealloc_task);
vif->dealloc_task = NULL;
}
if (vif->tx_irq) {
if (vif->tx_irq == vif->rx_irq)
unbind_from_irqhandler(vif->tx_irq, vif);
@ -493,6 +533,23 @@ void xenvif_disconnect(struct xenvif *vif)
void xenvif_free(struct xenvif *vif)
{
int i, unmap_timeout = 0;
for (i = 0; i < MAX_PENDING_REQS; ++i) {
if (vif->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) {
unmap_timeout++;
schedule_timeout(msecs_to_jiffies(1000));
if (unmap_timeout > 9 &&
net_ratelimit())
netdev_err(vif->dev,
"Page still granted! Index: %x\n",
i);
i = -1;
}
}
free_xenballooned_pages(MAX_PENDING_REQS, vif->mmap_pages);
netif_napi_del(&vif->napi);
unregister_netdev(vif->dev);

432
drivers/net/xen-netback/netback.c
View File

@ -101,10 +101,18 @@ static inline unsigned long idx_to_kaddr(struct xenvif *vif,
return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
}
/* Find the containing VIF's structure from a pointer in pending_tx_info array
*/
static inline struct xenvif* ubuf_to_vif(struct ubuf_info *ubuf)
{
return NULL;
u16 pending_idx = ubuf->desc;
struct pending_tx_info *temp =
container_of(ubuf, struct pending_tx_info, callback_struct);
return container_of(temp - pending_idx,
struct xenvif,
pending_tx_info[0]);
}
/* This is a miniumum size for the linear area to avoid lots of
* calls to __pskb_pull_tail() as we set up checksum offsets. The
* value 128 was chosen as it covers all IPv4 and most likely
@ -665,9 +673,12 @@ static void xenvif_tx_err(struct xenvif *vif,
struct xen_netif_tx_request *txp, RING_IDX end)
{
RING_IDX cons = vif->tx.req_cons;
unsigned long flags;
do {
spin_lock_irqsave(&vif->response_lock, flags);
make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
spin_unlock_irqrestore(&vif->response_lock, flags);
if (cons == end)
break;
txp = RING_GET_REQUEST(&vif->tx, cons++);
@ -799,10 +810,24 @@ struct xenvif_tx_cb {
#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
static struct gnttab_copy *xenvif_get_requests(struct xenvif *vif,
struct sk_buff *skb,
struct xen_netif_tx_request *txp,
struct gnttab_copy *gop)
static inline void xenvif_tx_create_gop(struct xenvif *vif,
u16 pending_idx,
struct xen_netif_tx_request *txp,
struct gnttab_map_grant_ref *gop)
{
vif->pages_to_map[gop-vif->tx_map_ops] = vif->mmap_pages[pending_idx];
gnttab_set_map_op(gop, idx_to_kaddr(vif, pending_idx),
GNTMAP_host_map | GNTMAP_readonly,
txp->gref, vif->domid);
memcpy(&vif->pending_tx_info[pending_idx].req, txp,
sizeof(*txp));
}
static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
struct sk_buff *skb,
struct xen_netif_tx_request *txp,
struct gnttab_map_grant_ref *gop)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
skb_frag_t *frags = shinfo->frags;
@ -823,83 +848,12 @@ static struct gnttab_copy *xenvif_get_requests(struct xenvif *vif,
/* Skip first skb fragment if it is on same page as header fragment. */
start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
/* Coalesce tx requests, at this point the packet passed in
* should be <= 64K. Any packets larger than 64K have been
* handled in xenvif_count_requests().
*/
for (shinfo->nr_frags = slot = start; slot < nr_slots;
shinfo->nr_frags++) {
struct pending_tx_info *pending_tx_info =
vif->pending_tx_info;
page = alloc_page(GFP_ATOMIC|__GFP_COLD);
if (!page)
goto err;
dst_offset = 0;
first = NULL;
while (dst_offset < PAGE_SIZE && slot < nr_slots) {
gop->flags = GNTCOPY_source_gref;
gop->source.u.ref = txp->gref;
gop->source.domid = vif->domid;
gop->source.offset = txp->offset;
gop->dest.domid = DOMID_SELF;
gop->dest.offset = dst_offset;
gop->dest.u.gmfn = virt_to_mfn(page_address(page));
if (dst_offset + txp->size > PAGE_SIZE) {
/* This page can only merge a portion
* of tx request. Do not increment any
* pointer / counter here. The txp
* will be dealt with in future
* rounds, eventually hitting the
* `else` branch.
*/
gop->len = PAGE_SIZE - dst_offset;
txp->offset += gop->len;
txp->size -= gop->len;
dst_offset += gop->len; /* quit loop */
} else {
/* This tx request can be merged in the page */
gop->len = txp->size;
dst_offset += gop->len;
for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
shinfo->nr_frags++, txp++, gop++) {
index = pending_index(vif->pending_cons++);
pending_idx = vif->pending_ring[index];
memcpy(&pending_tx_info[pending_idx].req, txp,
sizeof(*txp));
/* Poison these fields, corresponding
* fields for head tx req will be set
* to correct values after the loop.
*/
vif->mmap_pages[pending_idx] = (void *)(~0UL);
pending_tx_info[pending_idx].head =
INVALID_PENDING_RING_IDX;
if (!first) {
first = &pending_tx_info[pending_idx];
start_idx = index;
head_idx = pending_idx;
}
txp++;
slot++;
}
gop++;
}
first->req.offset = 0;
first->req.size = dst_offset;
first->head = start_idx;
vif->mmap_pages[head_idx] = page;
frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
xenvif_tx_create_gop(vif, pending_idx, txp, gop);
frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
}
BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
@ -919,11 +873,38 @@ err:
return NULL;
}
static inline void xenvif_grant_handle_set(struct xenvif *vif,
u16 pending_idx,
grant_handle_t handle)
{
if (unlikely(vif->grant_tx_handle[pending_idx] !=
NETBACK_INVALID_HANDLE)) {
netdev_err(vif->dev,
"Trying to overwrite active handle! pending_idx: %x\n",
pending_idx);
BUG();
}
vif->grant_tx_handle[pending_idx] = handle;
}
static inline void xenvif_grant_handle_reset(struct xenvif *vif,
u16 pending_idx)
{
if (unlikely(vif->grant_tx_handle[pending_idx] ==
NETBACK_INVALID_HANDLE)) {
netdev_err(vif->dev,
"Trying to unmap invalid handle! pending_idx: %x\n",
pending_idx);
BUG();
}
vif->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
}
static int xenvif_tx_check_gop(struct xenvif *vif,
struct sk_buff *skb,
struct gnttab_copy **gopp)
struct gnttab_map_grant_ref **gopp)
{
struct gnttab_copy *gop = *gopp;
struct gnttab_map_grant_ref *gop = *gopp;
u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
struct skb_shared_info *shinfo = skb_shinfo(skb);
struct pending_tx_info *tx_info;
@ -935,6 +916,8 @@ static int xenvif_tx_check_gop(struct xenvif *vif,
err = gop->status;
if (unlikely(err))
xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
else
xenvif_grant_handle_set(vif, pending_idx , gop->handle);
/* Skip first skb fragment if it is on same page as header fragment. */
start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
@ -948,18 +931,13 @@ static int xenvif_tx_check_gop(struct xenvif *vif,
head = tx_info->head;
/* Check error status: if okay then remember grant handle. */
do {
newerr = (++gop)->status;
if (newerr)
break;
peek = vif->pending_ring[pending_index(++head)];
} while (!pending_tx_is_head(vif, peek));
if (likely(!newerr)) {
xenvif_grant_handle_set(vif, pending_idx , gop->handle);
/* Had a previous error? Invalidate this fragment. */
if (unlikely(err))
xenvif_idx_release(vif, pending_idx,
XEN_NETIF_RSP_OKAY);
xenvif_idx_unmap(vif, pending_idx);
continue;
}
@ -972,11 +950,10 @@ static int xenvif_tx_check_gop(struct xenvif *vif,
/* First error: invalidate header and preceding fragments. */
pending_idx = XENVIF_TX_CB(skb)->pending_idx;
xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
xenvif_idx_unmap(vif, pending_idx);
for (j = start; j < i; j++) {
pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
xenvif_idx_release(vif, pending_idx,
XEN_NETIF_RSP_OKAY);
xenvif_idx_unmap(vif, pending_idx);
}
/* Remember the error: invalidate all subsequent fragments. */
@ -992,6 +969,10 @@ static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
struct skb_shared_info *shinfo = skb_shinfo(skb);
int nr_frags = shinfo->nr_frags;
int i;
u16 prev_pending_idx = INVALID_PENDING_IDX;
if (skb_shinfo(skb)->destructor_arg)
prev_pending_idx = XENVIF_TX_CB(skb)->pending_idx;
for (i = 0; i < nr_frags; i++) {
skb_frag_t *frag = shinfo->frags + i;
@ -1001,6 +982,17 @@ static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
pending_idx = frag_get_pending_idx(frag);
/* If this is not the first frag, chain it to the previous*/
if (unlikely(prev_pending_idx == INVALID_PENDING_IDX))
skb_shinfo(skb)->destructor_arg =
&vif->pending_tx_info[pending_idx].callback_struct;
else if (likely(pending_idx != prev_pending_idx))
vif->pending_tx_info[prev_pending_idx].callback_struct.ctx =
&(vif->pending_tx_info[pending_idx].callback_struct);
vif->pending_tx_info[pending_idx].callback_struct.ctx = NULL;
prev_pending_idx = pending_idx;
txp = &vif->pending_tx_info[pending_idx].req;
page = virt_to_page(idx_to_kaddr(vif, pending_idx));
__skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
@ -1008,10 +1000,15 @@ static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
skb->data_len += txp->size;
skb->truesize += txp->size;
/* Take an extra reference to offset xenvif_idx_release */
/* Take an extra reference to offset network stack's put_page */
get_page(vif->mmap_pages[pending_idx]);
xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
}
/* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc
* overlaps with "index", and "mapping" is not set. I think mapping
* should be set. If delivered to local stack, it would drop this
* skb in sk_filter unless the socket has the right to use it.
*/
skb->pfmemalloc = false;
}
static int xenvif_get_extras(struct xenvif *vif,
@ -1131,7 +1128,7 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
{
struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
struct gnttab_map_grant_ref *gop = vif->tx_map_ops, *request_gop;
struct sk_buff *skb;
int ret;
@ -1238,30 +1235,10 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
}
}
/* XXX could copy straight to head */
page = xenvif_alloc_page(vif, pending_idx);
if (!page) {
kfree_skb(skb);
xenvif_tx_err(vif, &txreq, idx);
break;
}
gop->source.u.ref = txreq.gref;
gop->source.domid = vif->domid;
gop->source.offset = txreq.offset;
gop->dest.u.gmfn = virt_to_mfn(page_address(page));
gop->dest.domid = DOMID_SELF;
gop->dest.offset = txreq.offset;
gop->len = txreq.size;
gop->flags = GNTCOPY_source_gref;
xenvif_tx_create_gop(vif, pending_idx, &txreq, gop);
gop++;
memcpy(&vif->pending_tx_info[pending_idx].req,
&txreq, sizeof(txreq));
vif->pending_tx_info[pending_idx].head = index;
XENVIF_TX_CB(skb)->pending_idx = pending_idx;
__skb_put(skb, data_len);
@ -1290,17 +1267,17 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
vif->tx.req_cons = idx;
if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops))
if ((gop-vif->tx_map_ops) >= ARRAY_SIZE(vif->tx_map_ops))
break;
}
return gop - vif->tx_copy_ops;
return gop - vif->tx_map_ops;
}
static int xenvif_tx_submit(struct xenvif *vif)
{
struct gnttab_copy *gop = vif->tx_copy_ops;
struct gnttab_map_grant_ref *gop = vif->tx_map_ops;
struct sk_buff *skb;
int work_done = 0;
@ -1324,14 +1301,17 @@ static int xenvif_tx_submit(struct xenvif *vif)
memcpy(skb->data,
(void *)(idx_to_kaddr(vif, pending_idx)|txp->offset),
data_len);
vif->pending_tx_info[pending_idx].callback_struct.ctx = NULL;
if (data_len < txp->size) {
/* Append the packet payload as a fragment. */
txp->offset += data_len;
txp->size -= data_len;
skb_shinfo(skb)->destructor_arg =
&vif->pending_tx_info[pending_idx].callback_struct;
} else {
/* Schedule a response immediately. */
xenvif_idx_release(vif, pending_idx,
XEN_NETIF_RSP_OKAY);
skb_shinfo(skb)->destructor_arg = NULL;
xenvif_idx_unmap(vif, pending_idx);
}
if (txp->flags & XEN_NETTXF_csum_blank)
@ -1353,6 +1333,9 @@ static int xenvif_tx_submit(struct xenvif *vif)
if (checksum_setup(vif, skb)) {
netdev_dbg(vif->dev,
"Can't setup checksum in net_tx_action\n");
/* We have to set this flag to trigger the callback */
if (skb_shinfo(skb)->destructor_arg)
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
kfree_skb(skb);
continue;
}
@ -1378,6 +1361,14 @@ static int xenvif_tx_submit(struct xenvif *vif)
work_done++;
/* Set this flag right before netif_receive_skb, otherwise
* someone might think this packet already left netback, and
* do a skb_copy_ubufs while we are still in control of the
* skb. E.g. the __pskb_pull_tail earlier can do such thing.
*/
if (skb_shinfo(skb)->destructor_arg)
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
netif_receive_skb(skb);
}
@ -1386,14 +1377,111 @@ static int xenvif_tx_submit(struct xenvif *vif)
void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
{
return;
unsigned long flags;
pending_ring_idx_t index;
struct xenvif *vif = ubuf_to_vif(ubuf);
/* This is the only place where we grab this lock, to protect callbacks
* from each other.
*/
spin_lock_irqsave(&vif->callback_lock, flags);
do {
u16 pending_idx = ubuf->desc;
ubuf = (struct ubuf_info *) ubuf->ctx;
BUG_ON(vif->dealloc_prod - vif->dealloc_cons >=
MAX_PENDING_REQS);
index = pending_index(vif->dealloc_prod);
vif->dealloc_ring[index] = pending_idx;
/* Sync with xenvif_tx_dealloc_action:
* insert idx then incr producer.
*/
smp_wmb();
vif->dealloc_prod++;
} while (ubuf);
wake_up(&vif->dealloc_wq);
spin_unlock_irqrestore(&vif->callback_lock, flags);
if (RING_HAS_UNCONSUMED_REQUESTS(&vif->tx) &&
xenvif_tx_pending_slots_available(vif)) {
local_bh_disable();
napi_schedule(&vif->napi);
local_bh_enable();
}
}
static inline void xenvif_tx_dealloc_action(struct xenvif *vif)
{
struct gnttab_unmap_grant_ref *gop;
pending_ring_idx_t dc, dp;
u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
unsigned int i = 0;
dc = vif->dealloc_cons;
gop = vif->tx_unmap_ops;
/* Free up any grants we have finished using */
do {
dp = vif->dealloc_prod;
/* Ensure we see all indices enqueued by all
* xenvif_zerocopy_callback().
*/
smp_rmb();
while (dc != dp) {
BUG_ON(gop - vif->tx_unmap_ops > MAX_PENDING_REQS);
pending_idx =
vif->dealloc_ring[pending_index(dc++)];
pending_idx_release[gop-vif->tx_unmap_ops] =
pending_idx;
vif->pages_to_unmap[gop-vif->tx_unmap_ops] =
vif->mmap_pages[pending_idx];
gnttab_set_unmap_op(gop,
idx_to_kaddr(vif, pending_idx),
GNTMAP_host_map,
vif->grant_tx_handle[pending_idx]);
/* Btw. already unmapped? */
xenvif_grant_handle_reset(vif, pending_idx);
++gop;
}
} while (dp != vif->dealloc_prod);
vif->dealloc_cons = dc;
if (gop - vif->tx_unmap_ops > 0) {
int ret;
ret = gnttab_unmap_refs(vif->tx_unmap_ops,
NULL,
vif->pages_to_unmap,
gop - vif->tx_unmap_ops);
if (ret) {
netdev_err(vif->dev, "Unmap fail: nr_ops %x ret %d\n",
gop - vif->tx_unmap_ops, ret);
for (i = 0; i < gop - vif->tx_unmap_ops; ++i) {
if (gop[i].status != GNTST_okay)
netdev_err(vif->dev,
" host_addr: %llx handle: %x status: %d\n",
gop[i].host_addr,
gop[i].handle,
gop[i].status);
}
BUG();
}
}
for (i = 0; i < gop - vif->tx_unmap_ops; ++i)
xenvif_idx_release(vif, pending_idx_release[i],
XEN_NETIF_RSP_OKAY);
}
/* Called after netfront has transmitted */
int xenvif_tx_action(struct xenvif *vif, int budget)
{
unsigned nr_gops;
int work_done;
int work_done, ret;
if (unlikely(!tx_work_todo(vif)))
return 0;
@ -1403,7 +1491,11 @@ int xenvif_tx_action(struct xenvif *vif, int budget)
if (nr_gops == 0)
return 0;
gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
ret = gnttab_map_refs(vif->tx_map_ops,
NULL,
vif->pages_to_map,
nr_gops);
BUG_ON(ret);
work_done = xenvif_tx_submit(vif);
@ -1414,45 +1506,19 @@ static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
u8 status)
{
struct pending_tx_info *pending_tx_info;
pending_ring_idx_t head;
pending_ring_idx_t index;
u16 peek; /* peek into next tx request */
unsigned long flags;
BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL));
/* Already complete? */
if (vif->mmap_pages[pending_idx] == NULL)
return;
pending_tx_info = &vif->pending_tx_info[pending_idx];
head = pending_tx_info->head;
BUG_ON(!pending_tx_is_head(vif, head));
BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx);
do {
pending_ring_idx_t index;
pending_ring_idx_t idx = pending_index(head);
u16 info_idx = vif->pending_ring[idx];
pending_tx_info = &vif->pending_tx_info[info_idx];
pending_tx_info = &vif->pending_tx_info[pending_idx];
spin_lock_irqsave(&vif->response_lock, flags);
make_tx_response(vif, &pending_tx_info->req, status);
/* Setting any number other than
* INVALID_PENDING_RING_IDX indicates this slot is
* starting a new packet / ending a previous packet.
*/
pending_tx_info->head = 0;
index = pending_index(vif->pending_prod++);
vif->pending_ring[index] = vif->pending_ring[info_idx];
peek = vif->pending_ring[pending_index(++head)];
} while (!pending_tx_is_head(vif, peek));
put_page(vif->mmap_pages[pending_idx]);
vif->mmap_pages[pending_idx] = NULL;
index = pending_index(vif->pending_prod);
vif->pending_ring[index] = pending_idx;
/* TX shouldn't use the index before we give it back here */
mb();
vif->pending_prod++;
spin_unlock_irqrestore(&vif->response_lock, flags);
}
@ -1500,6 +1566,25 @@ static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
return resp;
}
void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx)
{
int ret;
struct gnttab_unmap_grant_ref tx_unmap_op;
gnttab_set_unmap_op(&tx_unmap_op,
idx_to_kaddr(vif, pending_idx),
GNTMAP_host_map,
vif->grant_tx_handle[pending_idx]);
/* Btw. already unmapped? */
xenvif_grant_handle_reset(vif, pending_idx);
ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
&vif->mmap_pages[pending_idx], 1);
BUG_ON(ret);
xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
}
static inline int rx_work_todo(struct xenvif *vif)
{
return !skb_queue_empty(&vif->rx_queue) &&
@ -1516,6 +1601,11 @@ static inline int tx_work_todo(struct xenvif *vif)
return 0;
}
static inline bool tx_dealloc_work_todo(struct xenvif *vif)
{
return vif->dealloc_cons != vif->dealloc_prod;
}
void xenvif_unmap_frontend_rings(struct xenvif *vif)
{
if (vif->tx.sring)
@ -1602,6 +1692,28 @@ int xenvif_kthread_guest_rx(void *data)
return 0;
}
int xenvif_dealloc_kthread(void *data)
{
struct xenvif *vif = data;
while (!kthread_should_stop()) {
wait_event_interruptible(vif->dealloc_wq,
tx_dealloc_work_todo(vif) ||
kthread_should_stop());
if (kthread_should_stop())
break;
xenvif_tx_dealloc_action(vif);
cond_resched();
}
/* Unmap anything remaining*/
if (tx_dealloc_work_todo(vif))
xenvif_tx_dealloc_action(vif);
return 0;
}
static int __init netback_init(void)
{
int rc = 0;