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-rw-r--r--drivers/block/xen-blkfront.c63
-rw-r--r--drivers/net/xen-netfront.c54
-rw-r--r--drivers/scsi/xen-scsifront.c3
-rw-r--r--drivers/usb/host/xen-hcd.c26
-rw-r--r--drivers/xen/gntalloc.c25
-rw-r--r--drivers/xen/grant-table.c71
-rw-r--r--drivers/xen/pvcalls-front.c8
-rw-r--r--drivers/xen/xenbus/xenbus_client.c24
-rw-r--r--include/xen/grant_table.h19
-rw-r--r--net/9p/trans_xen.c14
10 files changed, 173 insertions, 134 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index ca71a0585333..03b5fb341e58 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1288,7 +1288,8 @@ free_shadow:
rinfo->ring_ref[i] = GRANT_INVALID_REF;
}
}
- free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * XEN_PAGE_SIZE));
+ free_pages_exact(rinfo->ring.sring,
+ info->nr_ring_pages * XEN_PAGE_SIZE);
rinfo->ring.sring = NULL;
if (rinfo->irq)
@@ -1372,9 +1373,15 @@ static int blkif_get_final_status(enum blk_req_status s1,
return BLKIF_RSP_OKAY;
}
-static bool blkif_completion(unsigned long *id,
- struct blkfront_ring_info *rinfo,
- struct blkif_response *bret)
+/*
+ * Return values:
+ * 1 response processed.
+ * 0 missing further responses.
+ * -1 error while processing.
+ */
+static int blkif_completion(unsigned long *id,
+ struct blkfront_ring_info *rinfo,
+ struct blkif_response *bret)
{
int i = 0;
struct scatterlist *sg;
@@ -1397,7 +1404,7 @@ static bool blkif_completion(unsigned long *id,
/* Wait the second response if not yet here. */
if (s2->status < REQ_DONE)
- return false;
+ return 0;
bret->status = blkif_get_final_status(s->status,
s2->status);
@@ -1448,42 +1455,43 @@ static bool blkif_completion(unsigned long *id,
}
/* Add the persistent grant into the list of free grants */
for (i = 0; i < num_grant; i++) {
- if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
+ if (!gnttab_try_end_foreign_access(s->grants_used[i]->gref)) {
/*
* If the grant is still mapped by the backend (the
* backend has chosen to make this grant persistent)
* we add it at the head of the list, so it will be
* reused first.
*/
- if (!info->feature_persistent)
- pr_alert_ratelimited("backed has not unmapped grant: %u\n",
- s->grants_used[i]->gref);
+ if (!info->feature_persistent) {
+ pr_alert("backed has not unmapped grant: %u\n",
+ s->grants_used[i]->gref);
+ return -1;
+ }
list_add(&s->grants_used[i]->node, &rinfo->grants);
rinfo->persistent_gnts_c++;
} else {
/*
- * If the grant is not mapped by the backend we end the
- * foreign access and add it to the tail of the list,
- * so it will not be picked again unless we run out of
- * persistent grants.
+ * If the grant is not mapped by the backend we add it
+ * to the tail of the list, so it will not be picked
+ * again unless we run out of persistent grants.
*/
- gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
s->grants_used[i]->gref = GRANT_INVALID_REF;
list_add_tail(&s->grants_used[i]->node, &rinfo->grants);
}
}
if (s->req.operation == BLKIF_OP_INDIRECT) {
for (i = 0; i < INDIRECT_GREFS(num_grant); i++) {
- if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
- if (!info->feature_persistent)
- pr_alert_ratelimited("backed has not unmapped grant: %u\n",
- s->indirect_grants[i]->gref);
+ if (!gnttab_try_end_foreign_access(s->indirect_grants[i]->gref)) {
+ if (!info->feature_persistent) {
+ pr_alert("backed has not unmapped grant: %u\n",
+ s->indirect_grants[i]->gref);
+ return -1;
+ }
list_add(&s->indirect_grants[i]->node, &rinfo->grants);
rinfo->persistent_gnts_c++;
} else {
struct page *indirect_page;
- gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
/*
* Add the used indirect page back to the list of
* available pages for indirect grefs.
@@ -1498,7 +1506,7 @@ static bool blkif_completion(unsigned long *id,
}
}
- return true;
+ return 1;
}
static irqreturn_t blkif_interrupt(int irq, void *dev_id)
@@ -1564,12 +1572,17 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
}
if (bret.operation != BLKIF_OP_DISCARD) {
+ int ret;
+
/*
* We may need to wait for an extra response if the
* I/O request is split in 2
*/
- if (!blkif_completion(&id, rinfo, &bret))
+ ret = blkif_completion(&id, rinfo, &bret);
+ if (!ret)
continue;
+ if (unlikely(ret < 0))
+ goto err;
}
if (add_id_to_freelist(rinfo, id)) {
@@ -1676,8 +1689,7 @@ static int setup_blkring(struct xenbus_device *dev,
for (i = 0; i < info->nr_ring_pages; i++)
rinfo->ring_ref[i] = GRANT_INVALID_REF;
- sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
- get_order(ring_size));
+ sring = alloc_pages_exact(ring_size, GFP_NOIO);
if (!sring) {
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
return -ENOMEM;
@@ -1687,7 +1699,7 @@ static int setup_blkring(struct xenbus_device *dev,
err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref);
if (err < 0) {
- free_pages((unsigned long)sring, get_order(ring_size));
+ free_pages_exact(sring, ring_size);
rinfo->ring.sring = NULL;
goto fail;
}
@@ -2532,11 +2544,10 @@ static void purge_persistent_grants(struct blkfront_info *info)
list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants,
node) {
if (gnt_list_entry->gref == GRANT_INVALID_REF ||
- gnttab_query_foreign_access(gnt_list_entry->gref))
+ !gnttab_try_end_foreign_access(gnt_list_entry->gref))
continue;
list_del(&gnt_list_entry->node);
- gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL);
rinfo->persistent_gnts_c--;
gnt_list_entry->gref = GRANT_INVALID_REF;
list_add_tail(&gnt_list_entry->node, &rinfo->grants);
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 7748f07e2cf1..daa4e6106aac 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -424,14 +424,12 @@ static bool xennet_tx_buf_gc(struct netfront_queue *queue)
queue->tx_link[id] = TX_LINK_NONE;
skb = queue->tx_skbs[id];
queue->tx_skbs[id] = NULL;
- if (unlikely(gnttab_query_foreign_access(
- queue->grant_tx_ref[id]) != 0)) {
+ if (unlikely(!gnttab_end_foreign_access_ref(
+ queue->grant_tx_ref[id], GNTMAP_readonly))) {
dev_alert(dev,
"Grant still in use by backend domain\n");
goto err;
}
- gnttab_end_foreign_access_ref(
- queue->grant_tx_ref[id], GNTMAP_readonly);
gnttab_release_grant_reference(
&queue->gref_tx_head, queue->grant_tx_ref[id]);
queue->grant_tx_ref[id] = GRANT_INVALID_REF;
@@ -990,7 +988,6 @@ static int xennet_get_responses(struct netfront_queue *queue,
struct device *dev = &queue->info->netdev->dev;
struct bpf_prog *xdp_prog;
struct xdp_buff xdp;
- unsigned long ret;
int slots = 1;
int err = 0;
u32 verdict;
@@ -1032,8 +1029,13 @@ static int xennet_get_responses(struct netfront_queue *queue,
goto next;
}
- ret = gnttab_end_foreign_access_ref(ref, 0);
- BUG_ON(!ret);
+ if (!gnttab_end_foreign_access_ref(ref, 0)) {
+ dev_alert(dev,
+ "Grant still in use by backend domain\n");
+ queue->info->broken = true;
+ dev_alert(dev, "Disabled for further use\n");
+ return -EINVAL;
+ }
gnttab_release_grant_reference(&queue->gref_rx_head, ref);
@@ -1254,6 +1256,10 @@ static int xennet_poll(struct napi_struct *napi, int budget)
&need_xdp_flush);
if (unlikely(err)) {
+ if (queue->info->broken) {
+ spin_unlock(&queue->rx_lock);
+ return 0;
+ }
err:
while ((skb = __skb_dequeue(&tmpq)))
__skb_queue_tail(&errq, skb);
@@ -1918,7 +1924,7 @@ static int setup_netfront(struct xenbus_device *dev,
struct netfront_queue *queue, unsigned int feature_split_evtchn)
{
struct xen_netif_tx_sring *txs;
- struct xen_netif_rx_sring *rxs;
+ struct xen_netif_rx_sring *rxs = NULL;
grant_ref_t gref;
int err;
@@ -1938,21 +1944,21 @@ static int setup_netfront(struct xenbus_device *dev,
err = xenbus_grant_ring(dev, txs, 1, &gref);
if (err < 0)
- goto grant_tx_ring_fail;
+ goto fail;
queue->tx_ring_ref = gref;
rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
if (!rxs) {
err = -ENOMEM;
xenbus_dev_fatal(dev, err, "allocating rx ring page");
- goto alloc_rx_ring_fail;
+ goto fail;
}
SHARED_RING_INIT(rxs);
FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
err = xenbus_grant_ring(dev, rxs, 1, &gref);
if (err < 0)
- goto grant_rx_ring_fail;
+ goto fail;
queue->rx_ring_ref = gref;
if (feature_split_evtchn)
@@ -1965,22 +1971,28 @@ static int setup_netfront(struct xenbus_device *dev,
err = setup_netfront_single(queue);
if (err)
- goto alloc_evtchn_fail;
+ goto fail;
return 0;
/* If we fail to setup netfront, it is safe to just revoke access to
* granted pages because backend is not accessing it at this point.
*/
-alloc_evtchn_fail:
- gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
-grant_rx_ring_fail:
- free_page((unsigned long)rxs);
-alloc_rx_ring_fail:
- gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
-grant_tx_ring_fail:
- free_page((unsigned long)txs);
-fail:
+ fail:
+ if (queue->rx_ring_ref != GRANT_INVALID_REF) {
+ gnttab_end_foreign_access(queue->rx_ring_ref, 0,
+ (unsigned long)rxs);
+ queue->rx_ring_ref = GRANT_INVALID_REF;
+ } else {
+ free_page((unsigned long)rxs);
+ }
+ if (queue->tx_ring_ref != GRANT_INVALID_REF) {
+ gnttab_end_foreign_access(queue->tx_ring_ref, 0,
+ (unsigned long)txs);
+ queue->tx_ring_ref = GRANT_INVALID_REF;
+ } else {
+ free_page((unsigned long)txs);
+ }
return err;
}
diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index 12c10a5e3d93..7f421600cb66 100644
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -233,12 +233,11 @@ static void scsifront_gnttab_done(struct vscsifrnt_info *info,
return;
for (i = 0; i < shadow->nr_grants; i++) {
- if (unlikely(gnttab_query_foreign_access(shadow->gref[i]))) {
+ if (unlikely(!gnttab_try_end_foreign_access(shadow->gref[i]))) {
shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME
"grant still in use by backend\n");
BUG();
}
- gnttab_end_foreign_access(shadow->gref[i], 0, 0UL);
}
kfree(shadow->sg);
diff --git a/drivers/usb/host/xen-hcd.c b/drivers/usb/host/xen-hcd.c
index be09fd9bac58..19b8c7ed74cb 100644
--- a/drivers/usb/host/xen-hcd.c
+++ b/drivers/usb/host/xen-hcd.c
@@ -716,8 +716,9 @@ static int xenhcd_map_urb_for_request(struct xenhcd_info *info, struct urb *urb,
return 0;
}
-static void xenhcd_gnttab_done(struct usb_shadow *shadow)
+static void xenhcd_gnttab_done(struct xenhcd_info *info, unsigned int id)
{
+ struct usb_shadow *shadow = info->shadow + id;
int nr_segs = 0;
int i;
@@ -726,8 +727,10 @@ static void xenhcd_gnttab_done(struct usb_shadow *shadow)
if (xenusb_pipeisoc(shadow->req.pipe))
nr_segs += shadow->req.u.isoc.nr_frame_desc_segs;
- for (i = 0; i < nr_segs; i++)
- gnttab_end_foreign_access(shadow->req.seg[i].gref, 0, 0UL);
+ for (i = 0; i < nr_segs; i++) {
+ if (!gnttab_try_end_foreign_access(shadow->req.seg[i].gref))
+ xenhcd_set_error(info, "backend didn't release grant");
+ }
shadow->req.nr_buffer_segs = 0;
shadow->req.u.isoc.nr_frame_desc_segs = 0;
@@ -841,7 +844,9 @@ static void xenhcd_cancel_all_enqueued_urbs(struct xenhcd_info *info)
list_for_each_entry_safe(urbp, tmp, &info->in_progress_list, list) {
req_id = urbp->req_id;
if (!urbp->unlinked) {
- xenhcd_gnttab_done(&info->shadow[req_id]);
+ xenhcd_gnttab_done(info, req_id);
+ if (info->error)
+ return;
if (urbp->urb->status == -EINPROGRESS)
/* not dequeued */
xenhcd_giveback_urb(info, urbp->urb,
@@ -942,8 +947,7 @@ static int xenhcd_urb_request_done(struct xenhcd_info *info)
rp = info->urb_ring.sring->rsp_prod;
if (RING_RESPONSE_PROD_OVERFLOW(&info->urb_ring, rp)) {
xenhcd_set_error(info, "Illegal index on urb-ring");
- spin_unlock_irqrestore(&info->lock, flags);
- return 0;
+ goto err;
}
rmb(); /* ensure we see queued responses up to "rp" */
@@ -952,11 +956,13 @@ static int xenhcd_urb_request_done(struct xenhcd_info *info)
id = res.id;
if (id >= XENUSB_URB_RING_SIZE) {
xenhcd_set_error(info, "Illegal data on urb-ring");
- continue;
+ goto err;
}
if (likely(xenusb_pipesubmit(info->shadow[id].req.pipe))) {
- xenhcd_gnttab_done(&info->shadow[id]);
+ xenhcd_gnttab_done(info, id);
+ if (info->error)
+ goto err;
urb = info->shadow[id].urb;
if (likely(urb)) {
urb->actual_length = res.actual_length;
@@ -978,6 +984,10 @@ static int xenhcd_urb_request_done(struct xenhcd_info *info)
spin_unlock_irqrestore(&info->lock, flags);
return more_to_do;
+
+ err:
+ spin_unlock_irqrestore(&info->lock, flags);
+ return 0;
}
static int xenhcd_conn_notify(struct xenhcd_info *info)
diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c
index 3fa40c723e8e..edb0acd0b832 100644
--- a/drivers/xen/gntalloc.c
+++ b/drivers/xen/gntalloc.c
@@ -169,20 +169,14 @@ undo:
__del_gref(gref);
}
- /* It's possible for the target domain to map the just-allocated grant
- * references by blindly guessing their IDs; if this is done, then
- * __del_gref will leave them in the queue_gref list. They need to be
- * added to the global list so that we can free them when they are no
- * longer referenced.
- */
- if (unlikely(!list_empty(&queue_gref)))
- list_splice_tail(&queue_gref, &gref_list);
mutex_unlock(&gref_mutex);
return rc;
}
static void __del_gref(struct gntalloc_gref *gref)
{
+ unsigned long addr;
+
if (gref->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
uint8_t *tmp = kmap(gref->page);
tmp[gref->notify.pgoff] = 0;
@@ -196,21 +190,16 @@ static void __del_gref(struct gntalloc_gref *gref)
gref->notify.flags = 0;
if (gref->gref_id) {
- if (gnttab_query_foreign_access(gref->gref_id))
- return;
-
- if (!gnttab_end_foreign_access_ref(gref->gref_id, 0))
- return;
-
- gnttab_free_grant_reference(gref->gref_id);
+ if (gref->page) {
+ addr = (unsigned long)page_to_virt(gref->page);
+ gnttab_end_foreign_access(gref->gref_id, 0, addr);
+ } else
+ gnttab_free_grant_reference(gref->gref_id);
}
gref_size--;
list_del(&gref->next_gref);
- if (gref->page)
- __free_page(gref->page);
-
kfree(gref);
}
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 3729bea0c989..5c83d41766c8 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -134,12 +134,9 @@ struct gnttab_ops {
*/
unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
/*
- * Query the status of a grant entry. Ref parameter is reference of
- * queried grant entry, return value is the status of queried entry.
- * Detailed status(writing/reading) can be gotten from the return value
- * by bit operations.
+ * Read the frame number related to a given grant reference.
*/
- int (*query_foreign_access)(grant_ref_t ref);
+ unsigned long (*read_frame)(grant_ref_t ref);
};
struct unmap_refs_callback_data {
@@ -284,22 +281,6 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
}
EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
-static int gnttab_query_foreign_access_v1(grant_ref_t ref)
-{
- return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
-}
-
-static int gnttab_query_foreign_access_v2(grant_ref_t ref)
-{
- return grstatus[ref] & (GTF_reading|GTF_writing);
-}
-
-int gnttab_query_foreign_access(grant_ref_t ref)
-{
- return gnttab_interface->query_foreign_access(ref);
-}
-EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
-
static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
{
u16 flags, nflags;
@@ -353,6 +334,16 @@ int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
}
EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
+static unsigned long gnttab_read_frame_v1(grant_ref_t ref)
+{
+ return gnttab_shared.v1[ref].frame;
+}
+
+static unsigned long gnttab_read_frame_v2(grant_ref_t ref)
+{
+ return gnttab_shared.v2[ref].full_page.frame;
+}
+
struct deferred_entry {
struct list_head list;
grant_ref_t ref;
@@ -382,12 +373,9 @@ static void gnttab_handle_deferred(struct timer_list *unused)
spin_unlock_irqrestore(&gnttab_list_lock, flags);
if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
put_free_entry(entry->ref);
- if (entry->page) {
- pr_debug("freeing g.e. %#x (pfn %#lx)\n",
- entry->ref, page_to_pfn(entry->page));
- put_page(entry->page);
- } else
- pr_info("freeing g.e. %#x\n", entry->ref);
+ pr_debug("freeing g.e. %#x (pfn %#lx)\n",
+ entry->ref, page_to_pfn(entry->page));
+ put_page(entry->page);
kfree(entry);
entry = NULL;
} else {
@@ -412,9 +400,18 @@ static void gnttab_handle_deferred(struct timer_list *unused)
static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
struct page *page)
{
- struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+ struct deferred_entry *entry;
+ gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
const char *what = KERN_WARNING "leaking";
+ entry = kmalloc(sizeof(*entry), gfp);
+ if (!page) {
+ unsigned long gfn = gnttab_interface->read_frame(ref);
+
+ page = pfn_to_page(gfn_to_pfn(gfn));
+ get_page(page);
+ }
+
if (entry) {
unsigned long flags;
@@ -435,11 +432,21 @@ static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
what, ref, page ? page_to_pfn(page) : -1);
}
+int gnttab_try_end_foreign_access(grant_ref_t ref)
+{
+ int ret = _gnttab_end_foreign_access_ref(ref, 0);
+
+ if (ret)
+ put_free_entry(ref);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_try_end_foreign_access);
+
void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
unsigned long page)
{
- if (gnttab_end_foreign_access_ref(ref, readonly)) {
- put_free_entry(ref);
+ if (gnttab_try_end_foreign_access(ref)) {
if (page != 0)
put_page(virt_to_page(page));
} else
@@ -1417,7 +1424,7 @@ static const struct gnttab_ops gnttab_v1_ops = {
.update_entry = gnttab_update_entry_v1,
.end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
.end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
- .query_foreign_access = gnttab_query_foreign_access_v1,
+ .read_frame = gnttab_read_frame_v1,
};
static const struct gnttab_ops gnttab_v2_ops = {
@@ -1429,7 +1436,7 @@ static const struct gnttab_ops gnttab_v2_ops = {
.update_entry = gnttab_update_entry_v2,
.end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
.end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
- .query_foreign_access = gnttab_query_foreign_access_v2,
+ .read_frame = gnttab_read_frame_v2,
};
static bool gnttab_need_v2(void)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 3c9ae156b597..0ca351f30a6d 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -337,8 +337,8 @@ static void free_active_ring(struct sock_mapping *map)
if (!map->active.ring)
return;
- free_pages((unsigned long)map->active.data.in,
- map->active.ring->ring_order);
+ free_pages_exact(map->active.data.in,
+ PAGE_SIZE << map->active.ring->ring_order);
free_page((unsigned long)map->active.ring);
}
@@ -352,8 +352,8 @@ static int alloc_active_ring(struct sock_mapping *map)
goto out;
map->active.ring->ring_order = PVCALLS_RING_ORDER;
- bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
- PVCALLS_RING_ORDER);
+ bytes = alloc_pages_exact(PAGE_SIZE << PVCALLS_RING_ORDER,
+ GFP_KERNEL | __GFP_ZERO);
if (!bytes)
goto out;
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index e8bed1cb76ba..df6890681231 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -379,7 +379,14 @@ int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
unsigned int nr_pages, grant_ref_t *grefs)
{
int err;
- int i, j;
+ unsigned int i;
+ grant_ref_t gref_head;
+
+ err = gnttab_alloc_grant_references(nr_pages, &gref_head);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "granting access to ring page");
+ return err;
+ }
for (i = 0; i < nr_pages; i++) {
unsigned long gfn;
@@ -389,23 +396,14 @@ int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
else
gfn = virt_to_gfn(vaddr);
- err = gnttab_grant_foreign_access(dev->otherend_id, gfn, 0);
- if (err < 0) {
- xenbus_dev_fatal(dev, err,
- "granting access to ring page");
- goto fail;
- }
- grefs[i] = err;
+ grefs[i] = gnttab_claim_grant_reference(&gref_head);
+ gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id,
+ gfn, 0);
vaddr = vaddr + XEN_PAGE_SIZE;
}
return 0;
-
-fail:
- for (j = 0; j < i; j++)
- gnttab_end_foreign_access_ref(grefs[j], 0);
- return err;
}
EXPORT_SYMBOL_GPL(xenbus_grant_ring);
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index cb854df031ce..c9fea9389ebe 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -104,17 +104,32 @@ int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
* access has been ended, free the given page too. Access will be ended
* immediately iff the grant entry is not in use, otherwise it will happen
* some time later. page may be 0, in which case no freeing will occur.
+ * Note that the granted page might still be accessed (read or write) by the
+ * other side after gnttab_end_foreign_access() returns, so even if page was
+ * specified as 0 it is not allowed to just reuse the page for other
+ * purposes immediately. gnttab_end_foreign_access() will take an additional
+ * reference to the granted page in this case, which is dropped only after
+ * the grant is no longer in use.
+ * This requires that multi page allocations for areas subject to
+ * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing
+ * via free_pages_exact()) in order to avoid high order pages.
*/
void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
unsigned long page);
+/*
+ * End access through the given grant reference, iff the grant entry is
+ * no longer in use. In case of success ending foreign access, the
+ * grant reference is deallocated.
+ * Return 1 if the grant entry was freed, 0 if it is still in use.
+ */
+int gnttab_try_end_foreign_access(grant_ref_t ref);
+
int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
-int gnttab_query_foreign_access(grant_ref_t ref);
-
/*
* operations on reserved batches of grant references
*/
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index eb9fb55280ef..01f8067994d6 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -281,9 +281,9 @@ static void xen_9pfs_front_free(struct xen_9pfs_front_priv *priv)
ref = priv->rings[i].intf->ref[j];
gnttab_end_foreign_access(ref, 0, 0);
}
- free_pages((unsigned long)priv->rings[i].data.in,
- priv->rings[i].intf->ring_order -
- (PAGE_SHIFT - XEN_PAGE_SHIFT));
+ free_pages_exact(priv->rings[i].data.in,
+ 1UL << (priv->rings[i].intf->ring_order +
+ XEN_PAGE_SHIFT));
}
gnttab_end_foreign_access(priv->rings[i].ref, 0, 0);
free_page((unsigned long)priv->rings[i].intf);
@@ -322,8 +322,8 @@ static int xen_9pfs_front_alloc_dataring(struct xenbus_device *dev,
if (ret < 0)
goto out;
ring->ref = ret;
- bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
- order - (PAGE_SHIFT - XEN_PAGE_SHIFT));
+ bytes = alloc_pages_exact(1UL << (order + XEN_PAGE_SHIFT),
+ GFP_KERNEL | __GFP_ZERO);
if (!bytes) {
ret = -ENOMEM;
goto out;
@@ -354,9 +354,7 @@ out:
if (bytes) {
for (i--; i >= 0; i--)
gnttab_end_foreign_access(ring->intf->ref[i], 0, 0);
- free_pages((unsigned long)bytes,
- ring->intf->ring_order -
- (PAGE_SHIFT - XEN_PAGE_SHIFT));
+ free_pages_exact(bytes, 1UL << (order + XEN_PAGE_SHIFT));
}
gnttab_end_foreign_access(ring->ref, 0, 0);
free_page((unsigned long)ring->intf);
generated by cgit v1.2.3 (git 2.39.0) at 2025-01-13 17:48:51 +0300