Update Linux to v5.10.109

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz

Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 49b381e..5c83d41 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -64,7 +64,6 @@
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
-#include <asm/pgtable.h>
 #include <asm/sync_bitops.h>
 
 /* External tools reserve first few grant table entries. */
@@ -135,12 +134,9 @@
 	 */
 	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 {
@@ -285,22 +281,6 @@
 }
 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;
@@ -354,6 +334,16 @@
 }
 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;
@@ -383,12 +373,9 @@
 		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 {
@@ -413,9 +400,18 @@
 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;
 
@@ -436,11 +432,21 @@
 	       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
@@ -664,7 +670,6 @@
 	unsigned int nr_glist_frames, new_nr_glist_frames;
 	unsigned int grefs_per_frame;
 
-	BUG_ON(gnttab_interface == NULL);
 	grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
 
 	new_nr_grant_frames = nr_grant_frames + more_frames;
@@ -803,7 +808,7 @@
 {
 	int ret;
 
-	ret = alloc_xenballooned_pages(nr_pages, pages);
+	ret = xen_alloc_unpopulated_pages(nr_pages, pages);
 	if (ret < 0)
 		return ret;
 
@@ -815,6 +820,129 @@
 }
 EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
 
+#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
+static inline void cache_init(struct gnttab_page_cache *cache)
+{
+	cache->pages = NULL;
+}
+
+static inline bool cache_empty(struct gnttab_page_cache *cache)
+{
+	return !cache->pages;
+}
+
+static inline struct page *cache_deq(struct gnttab_page_cache *cache)
+{
+	struct page *page;
+
+	page = cache->pages;
+	cache->pages = page->zone_device_data;
+
+	return page;
+}
+
+static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
+{
+	page->zone_device_data = cache->pages;
+	cache->pages = page;
+}
+#else
+static inline void cache_init(struct gnttab_page_cache *cache)
+{
+	INIT_LIST_HEAD(&cache->pages);
+}
+
+static inline bool cache_empty(struct gnttab_page_cache *cache)
+{
+	return list_empty(&cache->pages);
+}
+
+static inline struct page *cache_deq(struct gnttab_page_cache *cache)
+{
+	struct page *page;
+
+	page = list_first_entry(&cache->pages, struct page, lru);
+	list_del(&page->lru);
+
+	return page;
+}
+
+static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
+{
+	list_add(&page->lru, &cache->pages);
+}
+#endif
+
+void gnttab_page_cache_init(struct gnttab_page_cache *cache)
+{
+	spin_lock_init(&cache->lock);
+	cache_init(cache);
+	cache->num_pages = 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
+
+int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cache->lock, flags);
+
+	if (cache_empty(cache)) {
+		spin_unlock_irqrestore(&cache->lock, flags);
+		return gnttab_alloc_pages(1, page);
+	}
+
+	page[0] = cache_deq(cache);
+	cache->num_pages--;
+
+	spin_unlock_irqrestore(&cache->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_page_cache_get);
+
+void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
+			   unsigned int num)
+{
+	unsigned long flags;
+	unsigned int i;
+
+	spin_lock_irqsave(&cache->lock, flags);
+
+	for (i = 0; i < num; i++)
+		cache_enq(cache, page[i]);
+	cache->num_pages += num;
+
+	spin_unlock_irqrestore(&cache->lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_page_cache_put);
+
+void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
+{
+	struct page *page[10];
+	unsigned int i = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cache->lock, flags);
+
+	while (cache->num_pages > num) {
+		page[i] = cache_deq(cache);
+		cache->num_pages--;
+		if (++i == ARRAY_SIZE(page)) {
+			spin_unlock_irqrestore(&cache->lock, flags);
+			gnttab_free_pages(i, page);
+			i = 0;
+			spin_lock_irqsave(&cache->lock, flags);
+		}
+	}
+
+	spin_unlock_irqrestore(&cache->lock, flags);
+
+	if (i != 0)
+		gnttab_free_pages(i, page);
+}
+EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink);
+
 void gnttab_pages_clear_private(int nr_pages, struct page **pages)
 {
 	int i;
@@ -838,7 +966,7 @@
 void gnttab_free_pages(int nr_pages, struct page **pages)
 {
 	gnttab_pages_clear_private(nr_pages, pages);
-	free_xenballooned_pages(nr_pages, pages);
+	xen_free_unpopulated_pages(nr_pages, pages);
 }
 EXPORT_SYMBOL_GPL(gnttab_free_pages);
 
@@ -1160,7 +1288,6 @@
 
 static unsigned int nr_status_frames(unsigned int nr_grant_frames)
 {
-	BUG_ON(gnttab_interface == NULL);
 	return gnttab_frames(nr_grant_frames, SPP);
 }
 
@@ -1297,7 +1424,7 @@
 	.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 = {
@@ -1309,7 +1436,7 @@
 	.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)
@@ -1388,7 +1515,6 @@
 	int rc;
 	unsigned int cur, extra;
 
-	BUG_ON(gnttab_interface == NULL);
 	cur = nr_grant_frames;
 	extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
 		 gnttab_interface->grefs_per_grant_frame);
@@ -1423,7 +1549,6 @@
 	/* Determine the maximum number of frames required for the
 	 * grant reference free list on the current hypervisor.
 	 */
-	BUG_ON(gnttab_interface == NULL);
 	max_nr_glist_frames = (max_nr_grant_frames *
 			       gnttab_interface->grefs_per_grant_frame / RPP);