Merge tag 'for-linus-5.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes and cleanups from Juergen Gross:

 - a fix in the Xen balloon driver avoiding hitting a BUG_ON() in some
   cases, plus a follow-on cleanup series for that driver

 - a patch for introducing non-blocking EFI callbacks in Xen's EFI
   driver, plu a cleanup patch for Xen EFI handling merging the x86 and
   ARM arch specific initialization into the Xen EFI driver

 - a fix of the Xen xenbus driver avoiding a self-deadlock when cleaning
   up after a user process has died

 - a fix for Xen on ARM after removal of ZONE_DMA

 - a cleanup patch for avoiding build warnings for Xen on ARM

* tag 'for-linus-5.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/xenbus: fix self-deadlock after killing user process
  xen/efi: have a common runtime setup function
  arm: xen: mm: use __GPF_DMA32 for arm64
  xen/balloon: Clear PG_offline in balloon_retrieve()
  xen/balloon: Mark pages PG_offline in balloon_append()
  xen/balloon: Drop __balloon_append()
  xen/balloon: Set pages PageOffline() in balloon_add_region()
  ARM: xen: unexport HYPERVISOR_platform_op function
  xen/efi: Set nonblocking callbacks

3 files changed, 72 insertions, 56 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 4e11de6cde81..5bae515c8e25 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -156,8 +156,10 @@ static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
 	(GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC)
 
 /* balloon_append: add the given page to the balloon. */
-static void __balloon_append(struct page *page)
+static void balloon_append(struct page *page)
 {
+	__SetPageOffline(page);
+
 	/* Lowmem is re-populated first, so highmem pages go at list tail. */
 	if (PageHighMem(page)) {
 		list_add_tail(&page->lru, &ballooned_pages);
@@ -169,11 +171,6 @@ static void __balloon_append(struct page *page)
 	wake_up(&balloon_wq);
 }
 
-static void balloon_append(struct page *page)
-{
-	__balloon_append(page);
-}
-
 /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
 static struct page *balloon_retrieve(bool require_lowmem)
 {
@@ -192,6 +189,7 @@ static struct page *balloon_retrieve(bool require_lowmem)
 	else
 		balloon_stats.balloon_low--;
 
+	__ClearPageOffline(page);
 	return page;
 }
 
@@ -377,8 +375,7 @@ static void xen_online_page(struct page *page, unsigned int order)
 	for (i = 0; i < size; i++) {
 		p = pfn_to_page(start_pfn + i);
 		__online_page_set_limits(p);
-		__SetPageOffline(p);
-		__balloon_append(p);
+		balloon_append(p);
 	}
 	mutex_unlock(&balloon_mutex);
 }
@@ -444,7 +441,6 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
 		xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]);
 
 		/* Relinquish the page back to the allocator. */
-		__ClearPageOffline(page);
 		free_reserved_page(page);
 	}
 
@@ -471,7 +467,6 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 			state = BP_EAGAIN;
 			break;
 		}
-		__SetPageOffline(page);
 		adjust_managed_page_count(page, -1);
 		xenmem_reservation_scrub_page(page);
 		list_add(&page->lru, &pages);
@@ -611,7 +606,6 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
 	while (pgno < nr_pages) {
 		page = balloon_retrieve(true);
 		if (page) {
-			__ClearPageOffline(page);
 			pages[pgno++] = page;
 #ifdef CONFIG_XEN_HAVE_PVMMU
 			/*
@@ -653,10 +647,8 @@ void free_xenballooned_pages(int nr_pages, struct page **pages)
 	mutex_lock(&balloon_mutex);
 
 	for (i = 0; i < nr_pages; i++) {
-		if (pages[i]) {
-			__SetPageOffline(pages[i]);
+		if (pages[i])
 			balloon_append(pages[i]);
-		}
 	}
 
 	balloon_stats.target_unpopulated -= nr_pages;
@@ -674,7 +666,6 @@ static void __init balloon_add_region(unsigned long start_pfn,
 				      unsigned long pages)
 {
 	unsigned long pfn, extra_pfn_end;
-	struct page *page;
 
 	/*
 	 * If the amount of usable memory has been limited (e.g., with
@@ -684,11 +675,10 @@ static void __init balloon_add_region(unsigned long start_pfn,
 	extra_pfn_end = min(max_pfn, start_pfn + pages);
 
 	for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) {
-		page = pfn_to_page(pfn);
 		/* totalram_pages and totalhigh_pages do not
 		   include the boot-time balloon extension, so
 		   don't subtract from it. */
-		__balloon_append(page);
+		balloon_append(pfn_to_page(pfn));
 	}
 
 	balloon_stats.total_pages += extra_pfn_end - start_pfn;
diff --git a/drivers/xen/efi.c b/drivers/xen/efi.c
index 89d60f8e3c18..d1ff2186ebb4 100644
--- a/drivers/xen/efi.c
+++ b/drivers/xen/efi.c
@@ -40,7 +40,7 @@
 
 #define efi_data(op)	(op.u.efi_runtime_call)
 
-efi_status_t xen_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
+static efi_status_t xen_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
 {
 	struct xen_platform_op op = INIT_EFI_OP(get_time);
 
@@ -61,9 +61,8 @@ efi_status_t xen_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_get_time);
 
-efi_status_t xen_efi_set_time(efi_time_t *tm)
+static efi_status_t xen_efi_set_time(efi_time_t *tm)
 {
 	struct xen_platform_op op = INIT_EFI_OP(set_time);
 
@@ -75,10 +74,10 @@ efi_status_t xen_efi_set_time(efi_time_t *tm)
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_set_time);
 
-efi_status_t xen_efi_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
-				     efi_time_t *tm)
+static efi_status_t xen_efi_get_wakeup_time(efi_bool_t *enabled,
+					    efi_bool_t *pending,
+					    efi_time_t *tm)
 {
 	struct xen_platform_op op = INIT_EFI_OP(get_wakeup_time);
 
@@ -98,9 +97,8 @@ efi_status_t xen_efi_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_get_wakeup_time);
 
-efi_status_t xen_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
+static efi_status_t xen_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 {
 	struct xen_platform_op op = INIT_EFI_OP(set_wakeup_time);
 
@@ -117,11 +115,10 @@ efi_status_t xen_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_set_wakeup_time);
 
-efi_status_t xen_efi_get_variable(efi_char16_t *name, efi_guid_t *vendor,
-				  u32 *attr, unsigned long *data_size,
-				  void *data)
+static efi_status_t xen_efi_get_variable(efi_char16_t *name, efi_guid_t *vendor,
+					 u32 *attr, unsigned long *data_size,
+					 void *data)
 {
 	struct xen_platform_op op = INIT_EFI_OP(get_variable);
 
@@ -141,11 +138,10 @@ efi_status_t xen_efi_get_variable(efi_char16_t *name, efi_guid_t *vendor,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_get_variable);
 
-efi_status_t xen_efi_get_next_variable(unsigned long *name_size,
-				       efi_char16_t *name,
-				       efi_guid_t *vendor)
+static efi_status_t xen_efi_get_next_variable(unsigned long *name_size,
+					      efi_char16_t *name,
+					      efi_guid_t *vendor)
 {
 	struct xen_platform_op op = INIT_EFI_OP(get_next_variable_name);
 
@@ -165,11 +161,10 @@ efi_status_t xen_efi_get_next_variable(unsigned long *name_size,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_get_next_variable);
 
-efi_status_t xen_efi_set_variable(efi_char16_t *name, efi_guid_t *vendor,
-				 u32 attr, unsigned long data_size,
-				 void *data)
+static efi_status_t xen_efi_set_variable(efi_char16_t *name, efi_guid_t *vendor,
+					 u32 attr, unsigned long data_size,
+					 void *data)
 {
 	struct xen_platform_op op = INIT_EFI_OP(set_variable);
 
@@ -186,11 +181,10 @@ efi_status_t xen_efi_set_variable(efi_char16_t *name, efi_guid_t *vendor,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_set_variable);
 
-efi_status_t xen_efi_query_variable_info(u32 attr, u64 *storage_space,
-					 u64 *remaining_space,
-					 u64 *max_variable_size)
+static efi_status_t xen_efi_query_variable_info(u32 attr, u64 *storage_space,
+						u64 *remaining_space,
+						u64 *max_variable_size)
 {
 	struct xen_platform_op op = INIT_EFI_OP(query_variable_info);
 
@@ -208,9 +202,8 @@ efi_status_t xen_efi_query_variable_info(u32 attr, u64 *storage_space,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_query_variable_info);
 
-efi_status_t xen_efi_get_next_high_mono_count(u32 *count)
+static efi_status_t xen_efi_get_next_high_mono_count(u32 *count)
 {
 	struct xen_platform_op op = INIT_EFI_OP(get_next_high_monotonic_count);
 
@@ -221,10 +214,9 @@ efi_status_t xen_efi_get_next_high_mono_count(u32 *count)
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_get_next_high_mono_count);
 
-efi_status_t xen_efi_update_capsule(efi_capsule_header_t **capsules,
-				    unsigned long count, unsigned long sg_list)
+static efi_status_t xen_efi_update_capsule(efi_capsule_header_t **capsules,
+				unsigned long count, unsigned long sg_list)
 {
 	struct xen_platform_op op = INIT_EFI_OP(update_capsule);
 
@@ -241,11 +233,9 @@ efi_status_t xen_efi_update_capsule(efi_capsule_header_t **capsules,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_update_capsule);
 
-efi_status_t xen_efi_query_capsule_caps(efi_capsule_header_t **capsules,
-					unsigned long count, u64 *max_size,
-					int *reset_type)
+static efi_status_t xen_efi_query_capsule_caps(efi_capsule_header_t **capsules,
+			unsigned long count, u64 *max_size, int *reset_type)
 {
 	struct xen_platform_op op = INIT_EFI_OP(query_capsule_capabilities);
 
@@ -264,10 +254,9 @@ efi_status_t xen_efi_query_capsule_caps(efi_capsule_header_t **capsules,
 
 	return efi_data(op).status;
 }
-EXPORT_SYMBOL_GPL(xen_efi_query_capsule_caps);
 
-void xen_efi_reset_system(int reset_type, efi_status_t status,
-			  unsigned long data_size, efi_char16_t *data)
+static void xen_efi_reset_system(int reset_type, efi_status_t status,
+				 unsigned long data_size, efi_char16_t *data)
 {
 	switch (reset_type) {
 	case EFI_RESET_COLD:
@@ -281,4 +270,25 @@ void xen_efi_reset_system(int reset_type, efi_status_t status,
 		BUG();
 	}
 }
-EXPORT_SYMBOL_GPL(xen_efi_reset_system);
+
+/*
+ * Set XEN EFI runtime services function pointers. Other fields of struct efi,
+ * e.g. efi.systab, will be set like normal EFI.
+ */
+void __init xen_efi_runtime_setup(void)
+{
+	efi.get_time			= xen_efi_get_time;
+	efi.set_time			= xen_efi_set_time;
+	efi.get_wakeup_time		= xen_efi_get_wakeup_time;
+	efi.set_wakeup_time		= xen_efi_set_wakeup_time;
+	efi.get_variable		= xen_efi_get_variable;
+	efi.get_next_variable		= xen_efi_get_next_variable;
+	efi.set_variable		= xen_efi_set_variable;
+	efi.set_variable_nonblocking	= xen_efi_set_variable;
+	efi.query_variable_info		= xen_efi_query_variable_info;
+	efi.query_variable_info_nonblocking = xen_efi_query_variable_info;
+	efi.update_capsule		= xen_efi_update_capsule;
+	efi.query_capsule_caps		= xen_efi_query_capsule_caps;
+	efi.get_next_high_mono_count	= xen_efi_get_next_high_mono_count;
+	efi.reset_system		= xen_efi_reset_system;
+}
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 08adc590f631..597af455a522 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -55,6 +55,7 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/miscdevice.h>
+#include <linux/workqueue.h>
 
 #include <xen/xenbus.h>
 #include <xen/xen.h>
@@ -116,6 +117,8 @@ struct xenbus_file_priv {
 	wait_queue_head_t read_waitq;
 
 	struct kref kref;
+
+	struct work_struct wq;
 };
 
 /* Read out any raw xenbus messages queued up. */
@@ -300,14 +303,14 @@ static void watch_fired(struct xenbus_watch *watch,
 	mutex_unlock(&adap->dev_data->reply_mutex);
 }
 
-static void xenbus_file_free(struct kref *kref)
+static void xenbus_worker(struct work_struct *wq)
 {
 	struct xenbus_file_priv *u;
 	struct xenbus_transaction_holder *trans, *tmp;
 	struct watch_adapter *watch, *tmp_watch;
 	struct read_buffer *rb, *tmp_rb;
 
-	u = container_of(kref, struct xenbus_file_priv, kref);
+	u = container_of(wq, struct xenbus_file_priv, wq);
 
 	/*
 	 * No need for locking here because there are no other users,
@@ -333,6 +336,18 @@ static void xenbus_file_free(struct kref *kref)
 	kfree(u);
 }
 
+static void xenbus_file_free(struct kref *kref)
+{
+	struct xenbus_file_priv *u;
+
+	/*
+	 * We might be called in xenbus_thread().
+	 * Use workqueue to avoid deadlock.
+	 */
+	u = container_of(kref, struct xenbus_file_priv, kref);
+	schedule_work(&u->wq);
+}
+
 static struct xenbus_transaction_holder *xenbus_get_transaction(
 	struct xenbus_file_priv *u, uint32_t tx_id)
 {
@@ -650,6 +665,7 @@ static int xenbus_file_open(struct inode *inode, struct file *filp)
 	INIT_LIST_HEAD(&u->watches);
 	INIT_LIST_HEAD(&u->read_buffers);
 	init_waitqueue_head(&u->read_waitq);
+	INIT_WORK(&u->wq, xenbus_worker);
 
 	mutex_init(&u->reply_mutex);
 	mutex_init(&u->msgbuffer_mutex);