Merge tag 'v4.6-rc7' into patchwork

Linux 4.6-rc7

* tag 'v4.6-rc7': (185 commits)
  Linux 4.6-rc7
  parisc: fix a bug when syscall number of tracee is __NR_Linux_syscalls
  x86/tsc: Read all ratio bits from MSR_PLATFORM_INFO
  mailmap: add John Paul Adrian Glaubitz
  byteswap: try to avoid __builtin_constant_p gcc bug
  lib/stackdepot: avoid to return 0 handle
  mm: fix kcompactd hang during memory offlining
  modpost: fix module autoloading for OF devices with generic compatible property
  proc: prevent accessing /proc/<PID>/environ until it's ready
  mm/zswap: provide unique zpool name
  mm: thp: kvm: fix memory corruption in KVM with THP enabled
  MAINTAINERS: fix Rajendra Nayak's address
  mm, cma: prevent nr_isolated_* counters from going negative
  mm: update min_free_kbytes from khugepaged after core initialization
  huge pagecache: mmap_sem is unlocked when truncation splits pmd
  rapidio/mport_cdev: fix uapi type definitions
  mm: memcontrol: let v2 cgroups follow changes in system swappiness
  mm: thp: correct split_huge_pages file permission
  maintainers: update rmk's email address(es)
  writeback: Fix performance regression in wb_over_bg_thresh()
  ...

14 files changed, 161 insertions, 91 deletions

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 14362a84c78e..3a932501d690 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -394,13 +394,13 @@ struct acpi_data_node {
 
 static inline bool is_acpi_node(struct fwnode_handle *fwnode)
 {
-	return fwnode && (fwnode->type == FWNODE_ACPI
+	return !IS_ERR_OR_NULL(fwnode) && (fwnode->type == FWNODE_ACPI
 		|| fwnode->type == FWNODE_ACPI_DATA);
 }
 
 static inline bool is_acpi_device_node(struct fwnode_handle *fwnode)
 {
-	return fwnode && fwnode->type == FWNODE_ACPI;
+	return !IS_ERR_OR_NULL(fwnode) && fwnode->type == FWNODE_ACPI;
 }
 
 static inline struct acpi_device *to_acpi_device_node(struct fwnode_handle *fwnode)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 21ee41b92e8a..f1d5c5acc8dd 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -171,12 +171,13 @@ void bpf_register_prog_type(struct bpf_prog_type_list *tl);
 void bpf_register_map_type(struct bpf_map_type_list *tl);
 
 struct bpf_prog *bpf_prog_get(u32 ufd);
+struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
 void bpf_prog_put(struct bpf_prog *prog);
 void bpf_prog_put_rcu(struct bpf_prog *prog);
 
 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
 struct bpf_map *__bpf_map_get(struct fd f);
-void bpf_map_inc(struct bpf_map *map, bool uref);
+struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref);
 void bpf_map_put_with_uref(struct bpf_map *map);
 void bpf_map_put(struct bpf_map *map);
 int bpf_map_precharge_memlock(u32 pages);
diff --git a/include/linux/hash.h b/include/linux/hash.h
index 1afde47e1528..79c52fa81cac 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -32,12 +32,28 @@
 #error Wordsize not 32 or 64
 #endif
 
+/*
+ * The above primes are actively bad for hashing, since they are
+ * too sparse. The 32-bit one is mostly ok, the 64-bit one causes
+ * real problems. Besides, the "prime" part is pointless for the
+ * multiplicative hash.
+ *
+ * Although a random odd number will do, it turns out that the golden
+ * ratio phi = (sqrt(5)-1)/2, or its negative, has particularly nice
+ * properties.
+ *
+ * These are the negative, (1 - phi) = (phi^2) = (3 - sqrt(5))/2.
+ * (See Knuth vol 3, section 6.4, exercise 9.)
+ */
+#define GOLDEN_RATIO_32 0x61C88647
+#define GOLDEN_RATIO_64 0x61C8864680B583EBull
+
 static __always_inline u64 hash_64(u64 val, unsigned int bits)
 {
 	u64 hash = val;
 
-#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
-	hash = hash * GOLDEN_RATIO_PRIME_64;
+#if BITS_PER_LONG == 64
+	hash = hash * GOLDEN_RATIO_64;
 #else
 	/*  Sigh, gcc can't optimise this alone like it does for 32 bits. */
 	u64 n = hash;
diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h
index d5569734f672..548fd535fd02 100644
--- a/include/linux/if_ether.h
+++ b/include/linux/if_ether.h
@@ -28,6 +28,11 @@ static inline struct ethhdr *eth_hdr(const struct sk_buff *skb)
 	return (struct ethhdr *)skb_mac_header(skb);
 }
 
+static inline struct ethhdr *inner_eth_hdr(const struct sk_buff *skb)
+{
+	return (struct ethhdr *)skb_inner_mac_header(skb);
+}
+
 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
 
 extern ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len);
diff --git a/include/linux/net.h b/include/linux/net.h
index 49175e4ced11..f840d77c6c31 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -246,7 +246,15 @@ do {								\
 	net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
 #define net_info_ratelimited(fmt, ...)				\
 	net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
-#if defined(DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG)
+#define net_dbg_ratelimited(fmt, ...)					\
+do {									\
+	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);			\
+	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT) &&	\
+	    net_ratelimit())						\
+		__dynamic_pr_debug(&descriptor, fmt, ##__VA_ARGS__);	\
+} while (0)
+#elif defined(DEBUG)
 #define net_dbg_ratelimited(fmt, ...)				\
 	net_ratelimited_function(pr_debug, fmt, ##__VA_ARGS__)
 #else
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8395308a2445..b3c46b019ac1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4004,7 +4004,7 @@ netdev_features_t netif_skb_features(struct sk_buff *skb);
 
 static inline bool net_gso_ok(netdev_features_t features, int gso_type)
 {
-	netdev_features_t feature = gso_type << NETIF_F_GSO_SHIFT;
+	netdev_features_t feature = (netdev_features_t)gso_type << NETIF_F_GSO_SHIFT;
 
 	/* check flags correspondence */
 	BUILD_BUG_ON(SKB_GSO_TCPV4   != (NETIF_F_TSO >> NETIF_F_GSO_SHIFT));
diff --git a/include/linux/of.h b/include/linux/of.h
index 7fcb681baadf..31758036787c 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -133,7 +133,7 @@ void of_core_init(void);
 
 static inline bool is_of_node(struct fwnode_handle *fwnode)
 {
-	return fwnode && fwnode->type == FWNODE_OF;
+	return !IS_ERR_OR_NULL(fwnode) && fwnode->type == FWNODE_OF;
 }
 
 static inline struct device_node *to_of_node(struct fwnode_handle *fwnode)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index f4ed4f1b0c77..6b052aa7b5b7 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -517,6 +517,27 @@ static inline int PageTransCompound(struct page *page)
 }
 
 /*
+ * PageTransCompoundMap is the same as PageTransCompound, but it also
+ * guarantees the primary MMU has the entire compound page mapped
+ * through pmd_trans_huge, which in turn guarantees the secondary MMUs
+ * can also map the entire compound page. This allows the secondary
+ * MMUs to call get_user_pages() only once for each compound page and
+ * to immediately map the entire compound page with a single secondary
+ * MMU fault. If there will be a pmd split later, the secondary MMUs
+ * will get an update through the MMU notifier invalidation through
+ * split_huge_pmd().
+ *
+ * Unlike PageTransCompound, this is safe to be called only while
+ * split_huge_pmd() cannot run from under us, like if protected by the
+ * MMU notifier, otherwise it may result in page->_mapcount < 0 false
+ * positives.
+ */
+static inline int PageTransCompoundMap(struct page *page)
+{
+	return PageTransCompound(page) && atomic_read(&page->_mapcount) < 0;
+}
+
+/*
  * PageTransTail returns true for both transparent huge pages
  * and hugetlbfs pages, so it should only be called when it's known
  * that hugetlbfs pages aren't involved.
@@ -559,6 +580,7 @@ static inline int TestClearPageDoubleMap(struct page *page)
 #else
 TESTPAGEFLAG_FALSE(TransHuge)
 TESTPAGEFLAG_FALSE(TransCompound)
+TESTPAGEFLAG_FALSE(TransCompoundMap)
 TESTPAGEFLAG_FALSE(TransTail)
 TESTPAGEFLAG_FALSE(DoubleMap)
 	TESTSETFLAG_FALSE(DoubleMap)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 2b83359c19ca..0a4cd4703f40 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -533,6 +533,10 @@ static inline swp_entry_t get_swap_page(void)
 #ifdef CONFIG_MEMCG
 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 {
+	/* Cgroup2 doesn't have per-cgroup swappiness */
+	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		return vm_swappiness;
+
 	/* root ? */
 	if (mem_cgroup_disabled() || !memcg->css.parent)
 		return vm_swappiness;
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 73ed2e951c02..35437c779da8 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -252,7 +252,9 @@ static inline netdev_features_t vxlan_features_check(struct sk_buff *skb,
 	    (skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
 	     skb->inner_protocol != htons(ETH_P_TEB) ||
 	     (skb_inner_mac_header(skb) - skb_transport_header(skb) !=
-	      sizeof(struct udphdr) + sizeof(struct vxlanhdr))))
+	      sizeof(struct udphdr) + sizeof(struct vxlanhdr)) ||
+	     (skb->ip_summed != CHECKSUM_NONE &&
+	      !can_checksum_protocol(features, inner_eth_hdr(skb)->h_proto))))
 		return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
 
 	return features;
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 6e0f5f01734c..c51afb71bfab 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -718,9 +718,9 @@ __SYSCALL(__NR_mlock2, sys_mlock2)
 #define __NR_copy_file_range 285
 __SYSCALL(__NR_copy_file_range, sys_copy_file_range)
 #define __NR_preadv2 286
-__SYSCALL(__NR_preadv2, sys_preadv2)
+__SC_COMP(__NR_preadv2, sys_preadv2, compat_sys_preadv2)
 #define __NR_pwritev2 287
-__SYSCALL(__NR_pwritev2, sys_pwritev2)
+__SC_COMP(__NR_pwritev2, sys_pwritev2, compat_sys_pwritev2)
 
 #undef __NR_syscalls
 #define __NR_syscalls 288
diff --git a/include/linux/rio_mport_cdev.h b/include/uapi/linux/rio_mport_cdev.h
index b65d19df76d2..5796bf1d06ad 100644
--- a/include/linux/rio_mport_cdev.h
+++ b/include/uapi/linux/rio_mport_cdev.h
@@ -39,16 +39,16 @@
 #ifndef _RIO_MPORT_CDEV_H_
 #define _RIO_MPORT_CDEV_H_
 
-#ifndef __user
-#define __user
-#endif
+#include <linux/ioctl.h>
+#include <linux/types.h>
 
 struct rio_mport_maint_io {
-	uint32_t rioid;		/* destID of remote device */
-	uint32_t hopcount;	/* hopcount to remote device */
-	uint32_t offset;	/* offset in register space */
-	size_t length;		/* length in bytes */
-	void __user *buffer;	/* data buffer */
+	__u16 rioid;		/* destID of remote device */
+	__u8  hopcount;		/* hopcount to remote device */
+	__u8  pad0[5];
+	__u32 offset;		/* offset in register space */
+	__u32 length;		/* length in bytes */
+	__u64 buffer;		/* pointer to data buffer */
 };
 
 /*
@@ -66,22 +66,23 @@ struct rio_mport_maint_io {
 #define RIO_CAP_MAP_INB			(1 << 7)
 
 struct rio_mport_properties {
-	uint16_t hdid;
-	uint8_t id;			/* Physical port ID */
-	uint8_t  index;
-	uint32_t flags;
-	uint32_t sys_size;		/* Default addressing size */
-	uint8_t  port_ok;
-	uint8_t  link_speed;
-	uint8_t  link_width;
-	uint32_t dma_max_sge;
-	uint32_t dma_max_size;
-	uint32_t dma_align;
-	uint32_t transfer_mode;		/* Default transfer mode */
-	uint32_t cap_sys_size;		/* Capable system sizes */
-	uint32_t cap_addr_size;		/* Capable addressing sizes */
-	uint32_t cap_transfer_mode;	/* Capable transfer modes */
-	uint32_t cap_mport;		/* Mport capabilities */
+	__u16 hdid;
+	__u8  id;			/* Physical port ID */
+	__u8  index;
+	__u32 flags;
+	__u32 sys_size;		/* Default addressing size */
+	__u8  port_ok;
+	__u8  link_speed;
+	__u8  link_width;
+	__u8  pad0;
+	__u32 dma_max_sge;
+	__u32 dma_max_size;
+	__u32 dma_align;
+	__u32 transfer_mode;		/* Default transfer mode */
+	__u32 cap_sys_size;		/* Capable system sizes */
+	__u32 cap_addr_size;		/* Capable addressing sizes */
+	__u32 cap_transfer_mode;	/* Capable transfer modes */
+	__u32 cap_mport;		/* Mport capabilities */
 };
 
 /*
@@ -93,54 +94,57 @@ struct rio_mport_properties {
 #define RIO_PORTWRITE	(1 << 1)
 
 struct rio_doorbell {
-	uint32_t rioid;
-	uint16_t payload;
+	__u16 rioid;
+	__u16 payload;
 };
 
 struct rio_doorbell_filter {
-	uint32_t rioid;			/* 0xffffffff to match all ids */
-	uint16_t low;
-	uint16_t high;
+	__u16 rioid;	/* Use RIO_INVALID_DESTID to match all ids */
+	__u16 low;
+	__u16 high;
+	__u16 pad0;
 };
 
 
 struct rio_portwrite {
-	uint32_t payload[16];
+	__u32 payload[16];
 };
 
 struct rio_pw_filter {
-	uint32_t mask;
-	uint32_t low;
-	uint32_t high;
+	__u32 mask;
+	__u32 low;
+	__u32 high;
+	__u32 pad0;
 };
 
 /* RapidIO base address for inbound requests set to value defined below
  * indicates that no specific RIO-to-local address translation is requested
  * and driver should use direct (one-to-one) address mapping.
 */
-#define RIO_MAP_ANY_ADDR	(uint64_t)(~((uint64_t) 0))
+#define RIO_MAP_ANY_ADDR	(__u64)(~((__u64) 0))
 
 struct rio_mmap {
-	uint32_t rioid;
-	uint64_t rio_addr;
-	uint64_t length;
-	uint64_t handle;
-	void *address;
+	__u16 rioid;
+	__u16 pad0[3];
+	__u64 rio_addr;
+	__u64 length;
+	__u64 handle;
+	__u64 address;
 };
 
 struct rio_dma_mem {
-	uint64_t length;		/* length of DMA memory */
-	uint64_t dma_handle;		/* handle associated with this memory */
-	void *buffer;			/* pointer to this memory */
+	__u64 length;		/* length of DMA memory */
+	__u64 dma_handle;	/* handle associated with this memory */
+	__u64 address;
 };
 
-
 struct rio_event {
-	unsigned int header;	/* event type RIO_DOORBELL or RIO_PORTWRITE */
+	__u32 header;	/* event type RIO_DOORBELL or RIO_PORTWRITE */
 	union {
 		struct rio_doorbell doorbell;	/* header for RIO_DOORBELL */
 		struct rio_portwrite portwrite; /* header for RIO_PORTWRITE */
 	} u;
+	__u32 pad0;
 };
 
 enum rio_transfer_sync {
@@ -184,35 +188,37 @@ enum rio_exchange {
 };
 
 struct rio_transfer_io {
-	uint32_t rioid;			/* Target destID */
-	uint64_t rio_addr;		/* Address in target's RIO mem space */
-	enum rio_exchange method;	/* Data exchange method */
-	void __user *loc_addr;
-	uint64_t handle;
-	uint64_t offset;		/* Offset in buffer */
-	uint64_t length;		/* Length in bytes */
-	uint32_t completion_code;	/* Completion code for this transfer */
+	__u64 rio_addr;	/* Address in target's RIO mem space */
+	__u64 loc_addr;
+	__u64 handle;
+	__u64 offset;	/* Offset in buffer */
+	__u64 length;	/* Length in bytes */
+	__u16 rioid;	/* Target destID */
+	__u16 method;	/* Data exchange method, one of rio_exchange enum */
+	__u32 completion_code;	/* Completion code for this transfer */
 };
 
 struct rio_transaction {
-	uint32_t transfer_mode;		/* Data transfer mode */
-	enum rio_transfer_sync sync;	/* Synchronization method */
-	enum rio_transfer_dir dir;	/* Transfer direction */
-	size_t count;			/* Number of transfers */
-	struct rio_transfer_io __user *block;	/* Array of <count> transfers */
+	__u64 block;	/* Pointer to array of <count> transfers */
+	__u32 count;	/* Number of transfers */
+	__u32 transfer_mode;	/* Data transfer mode */
+	__u16 sync;	/* Synch method, one of rio_transfer_sync enum */
+	__u16 dir;	/* Transfer direction, one of rio_transfer_dir enum */
+	__u32 pad0;
 };
 
 struct rio_async_tx_wait {
-	uint32_t token;		/* DMA transaction ID token */
-	uint32_t timeout;	/* Wait timeout in msec, if 0 use default TO */
+	__u32 token;	/* DMA transaction ID token */
+	__u32 timeout;	/* Wait timeout in msec, if 0 use default TO */
 };
 
 #define RIO_MAX_DEVNAME_SZ	20
 
 struct rio_rdev_info {
-	uint32_t destid;
-	uint8_t hopcount;
-	uint32_t comptag;
+	__u16 destid;
+	__u8 hopcount;
+	__u8 pad0;
+	__u32 comptag;
 	char name[RIO_MAX_DEVNAME_SZ + 1];
 };
 
@@ -220,11 +226,11 @@ struct rio_rdev_info {
 #define RIO_MPORT_DRV_MAGIC           'm'
 
 #define RIO_MPORT_MAINT_HDID_SET	\
-	_IOW(RIO_MPORT_DRV_MAGIC, 1, uint16_t)
+	_IOW(RIO_MPORT_DRV_MAGIC, 1, __u16)
 #define RIO_MPORT_MAINT_COMPTAG_SET	\
-	_IOW(RIO_MPORT_DRV_MAGIC, 2, uint32_t)
+	_IOW(RIO_MPORT_DRV_MAGIC, 2, __u32)
 #define RIO_MPORT_MAINT_PORT_IDX_GET	\
-	_IOR(RIO_MPORT_DRV_MAGIC, 3, uint32_t)
+	_IOR(RIO_MPORT_DRV_MAGIC, 3, __u32)
 #define RIO_MPORT_GET_PROPERTIES \
 	_IOR(RIO_MPORT_DRV_MAGIC, 4, struct rio_mport_properties)
 #define RIO_MPORT_MAINT_READ_LOCAL \
@@ -244,9 +250,9 @@ struct rio_rdev_info {
 #define RIO_DISABLE_PORTWRITE_RANGE	\
 	_IOW(RIO_MPORT_DRV_MAGIC, 12, struct rio_pw_filter)
 #define RIO_SET_EVENT_MASK		\
-	_IOW(RIO_MPORT_DRV_MAGIC, 13, unsigned int)
+	_IOW(RIO_MPORT_DRV_MAGIC, 13, __u32)
 #define RIO_GET_EVENT_MASK		\
-	_IOR(RIO_MPORT_DRV_MAGIC, 14, unsigned int)
+	_IOR(RIO_MPORT_DRV_MAGIC, 14, __u32)
 #define RIO_MAP_OUTBOUND \
 	_IOWR(RIO_MPORT_DRV_MAGIC, 15, struct rio_mmap)
 #define RIO_UNMAP_OUTBOUND \
@@ -254,11 +260,11 @@ struct rio_rdev_info {
 #define RIO_MAP_INBOUND \
 	_IOWR(RIO_MPORT_DRV_MAGIC, 17, struct rio_mmap)
 #define RIO_UNMAP_INBOUND \
-	_IOW(RIO_MPORT_DRV_MAGIC, 18, uint64_t)
+	_IOW(RIO_MPORT_DRV_MAGIC, 18, __u64)
 #define RIO_ALLOC_DMA \
 	_IOWR(RIO_MPORT_DRV_MAGIC, 19, struct rio_dma_mem)
 #define RIO_FREE_DMA \
-	_IOW(RIO_MPORT_DRV_MAGIC, 20, uint64_t)
+	_IOW(RIO_MPORT_DRV_MAGIC, 20, __u64)
 #define RIO_TRANSFER \
 	_IOWR(RIO_MPORT_DRV_MAGIC, 21, struct rio_transaction)
 #define RIO_WAIT_FOR_ASYNC \
diff --git a/include/uapi/linux/swab.h b/include/uapi/linux/swab.h
index 3f10e5317b46..8f3a8f606fd9 100644
--- a/include/uapi/linux/swab.h
+++ b/include/uapi/linux/swab.h
@@ -45,9 +45,7 @@
 
 static inline __attribute_const__ __u16 __fswab16(__u16 val)
 {
-#ifdef __HAVE_BUILTIN_BSWAP16__
-	return __builtin_bswap16(val);
-#elif defined (__arch_swab16)
+#if defined (__arch_swab16)
 	return __arch_swab16(val);
 #else
 	return ___constant_swab16(val);
@@ -56,9 +54,7 @@ static inline __attribute_const__ __u16 __fswab16(__u16 val)
 
 static inline __attribute_const__ __u32 __fswab32(__u32 val)
 {
-#ifdef __HAVE_BUILTIN_BSWAP32__
-	return __builtin_bswap32(val);
-#elif defined(__arch_swab32)
+#if defined(__arch_swab32)
 	return __arch_swab32(val);
 #else
 	return ___constant_swab32(val);
@@ -67,9 +63,7 @@ static inline __attribute_const__ __u32 __fswab32(__u32 val)
 
 static inline __attribute_const__ __u64 __fswab64(__u64 val)
 {
-#ifdef __HAVE_BUILTIN_BSWAP64__
-	return __builtin_bswap64(val);
-#elif defined (__arch_swab64)
+#if defined (__arch_swab64)
 	return __arch_swab64(val);
 #elif defined(__SWAB_64_THRU_32__)
 	__u32 h = val >> 32;
@@ -102,28 +96,40 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val)
  * __swab16 - return a byteswapped 16-bit value
  * @x: value to byteswap
  */
+#ifdef __HAVE_BUILTIN_BSWAP16__
+#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
+#else
 #define __swab16(x)				\
 	(__builtin_constant_p((__u16)(x)) ?	\
 	___constant_swab16(x) :			\
 	__fswab16(x))
+#endif
 
 /**
  * __swab32 - return a byteswapped 32-bit value
  * @x: value to byteswap
  */
+#ifdef __HAVE_BUILTIN_BSWAP32__
+#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
+#else
 #define __swab32(x)				\
 	(__builtin_constant_p((__u32)(x)) ?	\
 	___constant_swab32(x) :			\
 	__fswab32(x))
+#endif
 
 /**
  * __swab64 - return a byteswapped 64-bit value
  * @x: value to byteswap
  */
+#ifdef __HAVE_BUILTIN_BSWAP64__
+#define __swab64(x) (__u64)__builtin_bswap64((__u64)(x))
+#else
 #define __swab64(x)				\
 	(__builtin_constant_p((__u64)(x)) ?	\
 	___constant_swab64(x) :			\
 	__fswab64(x))
+#endif
 
 /**
  * __swahw32 - return a word-swapped 32-bit value
diff --git a/include/xen/page.h b/include/xen/page.h
index 96294ac93755..9dc46cb8a0fd 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -15,9 +15,9 @@
  */
 
 #define xen_pfn_to_page(xen_pfn)	\
-	((pfn_to_page(((unsigned long)(xen_pfn) << XEN_PAGE_SHIFT) >> PAGE_SHIFT)))
+	(pfn_to_page((unsigned long)(xen_pfn) >> (PAGE_SHIFT - XEN_PAGE_SHIFT)))
 #define page_to_xen_pfn(page)		\
-	(((page_to_pfn(page)) << PAGE_SHIFT) >> XEN_PAGE_SHIFT)
+	((page_to_pfn(page)) << (PAGE_SHIFT - XEN_PAGE_SHIFT))
 
 #define XEN_PFN_PER_PAGE	(PAGE_SIZE / XEN_PAGE_SIZE)