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path: root/drivers/xen/grant-table.c
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Diffstat (limited to 'drivers/xen/grant-table.c')
-rw-r--r--drivers/xen/grant-table.c71
1 files changed, 39 insertions, 32 deletions
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)