xen: features and fixes for 4.10 rc0

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Merge tag 'for-linus-4.10-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:
 "Xen features and fixes for 4.10

  These are some fixes, a move of some arm related headers to share them
  between arm and arm64 and a series introducing a helper to make code
  more readable.

  The most notable change is David stepping down as maintainer of the
  Xen hypervisor interface. This results in me sending you the pull
  requests for Xen related code from now on"

* tag 'for-linus-4.10-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (29 commits)
  xen/balloon: Only mark a page as managed when it is released
  xenbus: fix deadlock on writes to /proc/xen/xenbus
  xen/scsifront: don't request a slot on the ring until request is ready
  xen/x86: Increase xen_e820_map to E820_X_MAX possible entries
  x86: Make E820_X_MAX unconditionally larger than E820MAX
  xen/pci: Bubble up error and fix description.
  xen: xenbus: set error code on failure
  xen: set error code on failures
  arm/xen: Use alloc_percpu rather than __alloc_percpu
  arm/arm64: xen: Move shared architecture headers to include/xen/arm
  xen/events: use xen_vcpu_id mapping for EVTCHNOP_status
  xen/gntdev: Use VM_MIXEDMAP instead of VM_IO to avoid NUMA balancing
  xen-scsifront: Add a missing call to kfree
  MAINTAINERS: update XEN HYPERVISOR INTERFACE
  xenfs: Use proc_create_mount_point() to create /proc/xen
  xen-platform: use builtin_pci_driver
  xen-netback: fix error handling output
  xen: make use of xenbus_read_unsigned() in xenbus
  xen: make use of xenbus_read_unsigned() in xen-pciback
  xen: make use of xenbus_read_unsigned() in xen-fbfront
  ...

drivers/xen/balloon.c

@@ -180,7 +180,6 @@ static void __balloon_append(struct page *page)
 static void balloon_append(struct page *page)
 {
 	__balloon_append(page);
-	adjust_managed_page_count(page, -1);
 }
 
 /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
@@ -201,8 +200,6 @@ static struct page *balloon_retrieve(bool require_lowmem)
 	else
 		balloon_stats.balloon_low--;
 
-	adjust_managed_page_count(page, 1);
-
 	return page;
 }
 
@@ -478,7 +475,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
 #endif
 
 		/* Relinquish the page back to the allocator. */
-		__free_reserved_page(page);
+		free_reserved_page(page);
 	}
 
 	balloon_stats.current_pages += rc;
@@ -509,6 +506,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 			state = BP_EAGAIN;
 			break;
 		}
+		adjust_managed_page_count(page, -1);
 		scrub_page(page);
 		list_add(&page->lru, &pages);
 	}

drivers/xen/events/events_base.c

@@ -947,7 +947,7 @@ static int find_virq(unsigned int virq, unsigned int cpu)
 			continue;
 		if (status.status != EVTCHNSTAT_virq)
 			continue;
-		if (status.u.virq == virq && status.vcpu == cpu) {
+		if (status.u.virq == virq && status.vcpu == xen_vcpu_nr(cpu)) {
 			rc = port;
 			break;
 		}

drivers/xen/gntalloc.c

@@ -127,18 +127,21 @@ static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
 	struct gntalloc_gref *gref, *next;
 
 	readonly = !(op->flags & GNTALLOC_FLAG_WRITABLE);
-	rc = -ENOMEM;
 	for (i = 0; i < op->count; i++) {
 		gref = kzalloc(sizeof(*gref), GFP_KERNEL);
-		if (!gref)
+		if (!gref) {
+			rc = -ENOMEM;
 			goto undo;
+		}
 		list_add_tail(&gref->next_gref, &queue_gref);
 		list_add_tail(&gref->next_file, &queue_file);
 		gref->users = 1;
 		gref->file_index = op->index + i * PAGE_SIZE;
 		gref->page = alloc_page(GFP_KERNEL|__GFP_ZERO);
-		if (!gref->page)
+		if (!gref->page) {
+			rc = -ENOMEM;
 			goto undo;
+		}
 
 		/* Grant foreign access to the page. */
 		rc = gnttab_grant_foreign_access(op->domid,

drivers/xen/gntdev.c

@@ -1007,7 +1007,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 
 	vma->vm_ops = &gntdev_vmops;
 
-	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
 
 	if (use_ptemod)
 		vma->vm_flags |= VM_DONTCOPY;

drivers/xen/platform-pci.c

@@ -125,8 +125,4 @@ static struct pci_driver platform_driver = {
 	.id_table =       platform_pci_tbl,
 };
 
-static int __init platform_pci_init(void)
-{
-	return pci_register_driver(&platform_driver);
-}
-device_initcall(platform_pci_init);
+builtin_pci_driver(platform_driver);

drivers/xen/xen-pciback/xenbus.c

@@ -362,7 +362,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 	int err = 0;
 	int num_devs;
 	int domain, bus, slot, func;
-	int substate;
+	unsigned int substate;
 	int i, len;
 	char state_str[64];
 	char dev_str[64];
@@ -395,10 +395,8 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 					 "configuration");
 			goto out;
 		}
-		err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
-				   "%d", &substate);
-		if (err != 1)
-			substate = XenbusStateUnknown;
+		substate = xenbus_read_unsigned(pdev->xdev->nodename, state_str,
+						XenbusStateUnknown);
 
 		switch (substate) {
 		case XenbusStateInitialising:

drivers/xen/xenbus/xenbus_dev_frontend.c

@@ -538,6 +538,8 @@ static int xenbus_file_open(struct inode *inode, struct file *filp)
 
 	nonseekable_open(inode, filp);
 
+	filp->f_mode &= ~FMODE_ATOMIC_POS; /* cdev-style semantics */
+
 	u = kzalloc(sizeof(*u), GFP_KERNEL);
 	if (u == NULL)
 		return -ENOMEM;

drivers/xen/xenbus/xenbus_probe.c

@@ -702,7 +702,7 @@ device_initcall(xenbus_probe_initcall);
  */
 static int __init xenstored_local_init(void)
 {
-	int err = 0;
+	int err = -ENOMEM;
 	unsigned long page = 0;
 	struct evtchn_alloc_unbound alloc_unbound;
 
@@ -826,7 +826,7 @@ static int __init xenbus_init(void)
 	 * Create xenfs mountpoint in /proc for compatibility with
 	 * utilities that expect to find "xenbus" under "/proc/xen".
 	 */
-	proc_mkdir("xen", NULL);
+	proc_create_mount_point("xen");
 #endif
 
 out_error:

drivers/xen/xenbus/xenbus_probe_backend.c

@@ -224,13 +224,7 @@ static int read_frontend_details(struct xenbus_device *xendev)
 
 int xenbus_dev_is_online(struct xenbus_device *dev)
 {
-	int rc, val;
-
-	rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
-	if (rc != 1)
-		val = 0; /* no online node present */
-
-	return val;
+	return !!xenbus_read_unsigned(dev->nodename, "online", 0);
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
 

drivers/xen/xenbus/xenbus_xs.c

@@ -559,6 +559,21 @@ int xenbus_scanf(struct xenbus_transaction t,
 }
 EXPORT_SYMBOL_GPL(xenbus_scanf);
 
+/* Read an (optional) unsigned value. */
+unsigned int xenbus_read_unsigned(const char *dir, const char *node,
+				  unsigned int default_val)
+{
+	unsigned int val;
+	int ret;
+
+	ret = xenbus_scanf(XBT_NIL, dir, node, "%u", &val);
+	if (ret <= 0)
+		val = default_val;
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_unsigned);
+
 /* Single printf and write: returns -errno or 0. */
 int xenbus_printf(struct xenbus_transaction t,
 		  const char *dir, const char *node, const char *fmt, ...)
@@ -672,7 +687,7 @@ static bool xen_strict_xenbus_quirk(void)
 }
 static void xs_reset_watches(void)
 {
-	int err, supported = 0;
+	int err;
 
 	if (!xen_hvm_domain() || xen_initial_domain())
 		return;
@@ -680,9 +695,8 @@ static void xs_reset_watches(void)
 	if (xen_strict_xenbus_quirk())
 		return;
 
-	err = xenbus_scanf(XBT_NIL, "control",
-			"platform-feature-xs_reset_watches", "%d", &supported);
-	if (err != 1 || !supported)
+	if (!xenbus_read_unsigned("control",
+				  "platform-feature-xs_reset_watches", 0))
 		return;
 
 	err = xs_error(xs_single(XBT_NIL, XS_RESET_WATCHES, "", NULL));