Fixes:

* Regression fix in xen privcmd fixing a memory leak.
  * Add Documentation for tmem driver.
  * Simplify and remove code in the tmem driver.
  * Cleanups.
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Merge tag 'stable/for-linus-3.10-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen fixes from Konrad Rzeszutek Wilk:
 - Regression fix in xen privcmd fixing a memory leak.
 - Add Documentation for tmem driver.
 - Simplify and remove code in the tmem driver.
 - Cleanups.

* tag 'stable/for-linus-3.10-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: Fixed assignment error in if statement
  xen/xenbus: Fixed over 80 character limit issue
  xen/xenbus: Fixed indentation error in switch case
  xen/tmem: Don't use self[ballooning|shrinking] if frontswap is off.
  xen/tmem: Remove the usage of '[no|]selfballoon' and use 'tmem.selfballooning' bool instead.
  xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.
  xen/tmem: Remove the boot options and fold them in the tmem.X parameters.
  xen/tmem: s/disable_// and change the logic.
  xen/tmem: Fix compile warning.
  xen/tmem: Split out the different module/boot options.
  xen/tmem: Move all of the boot and module parameters to the top of the file.
  xen/tmem: Cleanup. Remove the parts that say temporary.
  xen/privcmd: fix condition in privcmd_close()

Documentation/kernel-parameters.txt

@@ -3005,6 +3005,27 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Force threading of all interrupt handlers except those
 			marked explicitly IRQF_NO_THREAD.
 
+	tmem		[KNL,XEN]
+			Enable the Transcendent memory driver if built-in.
+
+	tmem.cleancache=0|1 [KNL, XEN]
+			Default is on (1). Disable the usage of the cleancache
+			API to send anonymous pages to the hypervisor.
+
+	tmem.frontswap=0|1 [KNL, XEN]
+			Default is on (1). Disable the usage of the frontswap
+			API to send swap pages to the hypervisor. If disabled
+			the selfballooning and selfshrinking are force disabled.
+
+	tmem.selfballooning=0|1 [KNL, XEN]
+			Default is on (1). Disable the driving of swap pages
+			to the hypervisor.
+
+	tmem.selfshrinking=0|1 [KNL, XEN]
+			Default is on (1). Partial swapoff that immediately
+			transfers pages from Xen hypervisor back to the
+			kernel based on different criteria.
+
 	topology=	[S390]
 			Format: {off | on}
 			Specify if the kernel should make use of the cpu

drivers/xen/Kconfig

@@ -19,11 +19,10 @@ config XEN_SELFBALLOONING
 	  by the current usage of anonymous memory ("committed AS") and
 	  controlled by various sysfs-settable parameters.  Configuring
 	  FRONTSWAP is highly recommended; if it is not configured, self-
-	  ballooning is disabled by default but can be enabled with the
-	  'selfballooning' kernel boot parameter.  If FRONTSWAP is configured,
+	  ballooning is disabled by default. If FRONTSWAP is configured,
 	  frontswap-selfshrinking is enabled by default but can be disabled
-	  with the 'noselfshrink' kernel boot parameter; and self-ballooning
-	  is enabled by default but can be disabled with the 'noselfballooning'
+	  with the 'tmem.selfshrink=0' kernel boot parameter; and self-ballooning
+	  is enabled by default but can be disabled with the 'tmem.selfballooning=0'
 	  kernel boot parameter.  Note that systems without a sufficiently
 	  large swap device should not enable self-ballooning.
 

drivers/xen/balloon.c

@@ -407,7 +407,8 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 		nr_pages = ARRAY_SIZE(frame_list);
 
 	for (i = 0; i < nr_pages; i++) {
-		if ((page = alloc_page(gfp)) == NULL) {
+		page = alloc_page(gfp);
+		if (page == NULL) {
 			nr_pages = i;
 			state = BP_EAGAIN;
 			break;

drivers/xen/privcmd.c

@@ -504,7 +504,7 @@ static void privcmd_close(struct vm_area_struct *vma)
 	struct page **pages = vma->vm_private_data;
 	int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 
-	if (!xen_feature(XENFEAT_auto_translated_physmap || !numpgs || !pages))
+	if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
 		return;
 
 	xen_unmap_domain_mfn_range(vma, numpgs, pages);

drivers/xen/tmem.c

@@ -11,11 +11,7 @@
 #include <linux/init.h>
 #include <linux/pagemap.h>
 #include <linux/cleancache.h>
-
-/* temporary ifdef until include/linux/frontswap.h is upstream */
-#ifdef CONFIG_FRONTSWAP
 #include <linux/frontswap.h>
-#endif
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
@@ -24,6 +20,34 @@
 #include <asm/xen/hypervisor.h>
 #include <xen/tmem.h>
 
+#ifndef CONFIG_XEN_TMEM_MODULE
+bool __read_mostly tmem_enabled = false;
+
+static int __init enable_tmem(char *s)
+{
+	tmem_enabled = true;
+	return 1;
+}
+__setup("tmem", enable_tmem);
+#endif
+
+#ifdef CONFIG_CLEANCACHE
+static bool cleancache __read_mostly = true;
+module_param(cleancache, bool, S_IRUGO);
+static bool selfballooning __read_mostly = true;
+module_param(selfballooning, bool, S_IRUGO);
+#endif /* CONFIG_CLEANCACHE */
+
+#ifdef CONFIG_FRONTSWAP
+static bool frontswap __read_mostly = true;
+module_param(frontswap, bool, S_IRUGO);
+#endif /* CONFIG_FRONTSWAP */
+
+#ifdef CONFIG_XEN_SELFBALLOONING
+static bool selfshrinking __read_mostly = true;
+module_param(selfshrinking, bool, S_IRUGO);
+#endif /* CONFIG_XEN_SELFBALLOONING */
+
 #define TMEM_CONTROL               0
 #define TMEM_NEW_POOL              1
 #define TMEM_DESTROY_POOL          2
@@ -129,16 +153,6 @@ static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
 	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
 }
 
-#ifndef CONFIG_XEN_TMEM_MODULE
-bool __read_mostly tmem_enabled = false;
-
-static int __init enable_tmem(char *s)
-{
-	tmem_enabled = true;
-	return 1;
-}
-__setup("tmem", enable_tmem);
-#endif
 
 #ifdef CONFIG_CLEANCACHE
 static int xen_tmem_destroy_pool(u32 pool_id)
@@ -230,20 +244,6 @@ static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
 	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
 }
 
-static bool disable_cleancache __read_mostly;
-static bool disable_selfballooning __read_mostly;
-#ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_cleancache, bool, S_IRUGO);
-module_param(disable_selfballooning, bool, S_IRUGO);
-#else
-static int __init no_cleancache(char *s)
-{
-	disable_cleancache = true;
-	return 1;
-}
-__setup("nocleancache", no_cleancache);
-#endif
-
 static struct cleancache_ops tmem_cleancache_ops = {
 	.put_page = tmem_cleancache_put_page,
 	.get_page = tmem_cleancache_get_page,
@@ -361,20 +361,6 @@ static void tmem_frontswap_init(unsigned ignored)
 		    xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
 }
 
-static bool disable_frontswap __read_mostly;
-static bool disable_frontswap_selfshrinking __read_mostly;
-#ifdef CONFIG_XEN_TMEM_MODULE
-module_param(disable_frontswap, bool, S_IRUGO);
-module_param(disable_frontswap_selfshrinking, bool, S_IRUGO);
-#else
-static int __init no_frontswap(char *s)
-{
-	disable_frontswap = true;
-	return 1;
-}
-__setup("nofrontswap", no_frontswap);
-#endif
-
 static struct frontswap_ops tmem_frontswap_ops = {
 	.store = tmem_frontswap_store,
 	.load = tmem_frontswap_load,
@@ -382,8 +368,6 @@ static struct frontswap_ops tmem_frontswap_ops = {
 	.invalidate_area = tmem_frontswap_flush_area,
 	.init = tmem_frontswap_init
 };
-#else	/* CONFIG_FRONTSWAP */
-#define disable_frontswap_selfshrinking 1
 #endif
 
 static int xen_tmem_init(void)
@@ -391,7 +375,7 @@ static int xen_tmem_init(void)
 	if (!xen_domain())
 		return 0;
 #ifdef CONFIG_FRONTSWAP
-	if (tmem_enabled && !disable_frontswap) {
+	if (tmem_enabled && frontswap) {
 		char *s = "";
 		struct frontswap_ops *old_ops =
 			frontswap_register_ops(&tmem_frontswap_ops);
@@ -408,7 +392,7 @@ static int xen_tmem_init(void)
 #endif
 #ifdef CONFIG_CLEANCACHE
 	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
-	if (tmem_enabled && !disable_cleancache) {
+	if (tmem_enabled && cleancache) {
 		char *s = "";
 		struct cleancache_ops *old_ops =
 			cleancache_register_ops(&tmem_cleancache_ops);
@@ -419,8 +403,15 @@ static int xen_tmem_init(void)
 	}
 #endif
 #ifdef CONFIG_XEN_SELFBALLOONING
-	xen_selfballoon_init(!disable_selfballooning,
-				!disable_frontswap_selfshrinking);
+	/*
+	 * There is no point of driving pages to the swap system if they
+	 * aren't going anywhere in tmem universe.
+	 */
+	if (!frontswap) {
+		selfshrinking = false;
+		selfballooning = false;
+	}
+	xen_selfballoon_init(selfballooning, selfshrinking);
 #endif
 	return 0;
 }

drivers/xen/xen-selfballoon.c

@@ -53,15 +53,12 @@
  * System configuration note: Selfballooning should not be enabled on
  * systems without a sufficiently large swap device configured; for best
  * results, it is recommended that total swap be increased by the size
- * of the guest memory.  Also, while technically not required to be
- * configured, it is highly recommended that frontswap also be configured
- * and enabled when selfballooning is running.  So, selfballooning
- * is disabled by default if frontswap is not configured and can only
- * be enabled with the "selfballooning" kernel boot option; similarly
- * selfballooning is enabled by default if frontswap is configured and
- * can be disabled with the "noselfballooning" kernel boot option.  Finally,
- * when frontswap is configured, frontswap-selfshrinking can be disabled
- * with the "noselfshrink" kernel boot option.
+ * of the guest memory. Note, that selfballooning should be disabled by default
+ * if frontswap is not configured.  Similarly selfballooning should be enabled
+ * by default if frontswap is configured and can be disabled with the
+ * "tmem.selfballooning=0" kernel boot option.  Finally, when frontswap is
+ * configured, frontswap-selfshrinking can be disabled  with the
+ * "tmem.selfshrink=0" kernel boot option.
  *
  * Selfballooning is disallowed in domain0 and force-disabled.
  *
@@ -120,9 +117,6 @@ static DECLARE_DELAYED_WORK(selfballoon_worker, selfballoon_process);
 /* Enable/disable with sysfs. */
 static bool frontswap_selfshrinking __read_mostly;
 
-/* Enable/disable with kernel boot option. */
-static bool use_frontswap_selfshrink = true;
-
 /*
  * The default values for the following parameters were deemed reasonable
  * by experimentation, may be workload-dependent, and can all be
@@ -176,35 +170,6 @@ static void frontswap_selfshrink(void)
 	frontswap_shrink(tgt_frontswap_pages);
 }
 
-static int __init xen_nofrontswap_selfshrink_setup(char *s)
-{
-	use_frontswap_selfshrink = false;
-	return 1;
-}
-
-__setup("noselfshrink", xen_nofrontswap_selfshrink_setup);
-
-/* Disable with kernel boot option. */
-static bool use_selfballooning = true;
-
-static int __init xen_noselfballooning_setup(char *s)
-{
-	use_selfballooning = false;
-	return 1;
-}
-
-__setup("noselfballooning", xen_noselfballooning_setup);
-#else /* !CONFIG_FRONTSWAP */
-/* Enable with kernel boot option. */
-static bool use_selfballooning;
-
-static int __init xen_selfballooning_setup(char *s)
-{
-	use_selfballooning = true;
-	return 1;
-}
-
-__setup("selfballooning", xen_selfballooning_setup);
 #endif /* CONFIG_FRONTSWAP */
 
 #define MB2PAGES(mb)	((mb) << (20 - PAGE_SHIFT))

drivers/xen/xenbus/xenbus_dev_backend.c

@@ -70,22 +70,21 @@ static long xenbus_alloc(domid_t domid)
 	return err;
 }
 
-static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned long data)
+static long xenbus_backend_ioctl(struct file *file, unsigned int cmd,
+				 unsigned long data)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
 	switch (cmd) {
-		case IOCTL_XENBUS_BACKEND_EVTCHN:
-			if (xen_store_evtchn > 0)
-				return xen_store_evtchn;
-			return -ENODEV;
-
-		case IOCTL_XENBUS_BACKEND_SETUP:
-			return xenbus_alloc(data);
-
-		default:
-			return -ENOTTY;
+	case IOCTL_XENBUS_BACKEND_EVTCHN:
+		if (xen_store_evtchn > 0)
+			return xen_store_evtchn;
+		return -ENODEV;
+	case IOCTL_XENBUS_BACKEND_SETUP:
+		return xenbus_alloc(data);
+	default:
+		return -ENOTTY;
 	}
 }