Merge tag 'imx-cleanup-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux into next/cleanup

Merge "ARM: imx: cleanup for 3.18" from Shawn Guo:

The i.MX cleanup for 3.18:
 - Reomve a few i.MX27 and i.MX1 board files
 - Remove imx_scu_standby_enable() since core code handles scu
   standby now
 - Remove unnecessary iomux declaration
 - Remove useless sound card property from vf610-twr dts

* tag 'imx-cleanup-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
  ARM: imx: Remove mach-mxt_td60 board file
  ARM: i.MX: Remove i.MX1 ADS board support
  ARM: dts: vf610-twr: remove useless property for sound card.
  ARM: imx: remove imx_scu_standby_enable()
  ARM: i.MX: Remove Phytec i.MX27 PCM038/PCM970 board files
  ARM: i.MX: Remove mach-cpuimx27sd board file
  ARM: imx: iomux: Do not export symbol without public declaration

Signed-off-by: Olof Johansson <olof@lixom.net>

3 files changed, 30 insertions, 8 deletions

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 0b49a0a5810..2bee072268d 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -64,7 +64,9 @@ bool kexec_in_progress = false;
 char __weak kexec_purgatory[0];
 size_t __weak kexec_purgatory_size = 0;
 
+#ifdef CONFIG_KEXEC_FILE
 static int kexec_calculate_store_digests(struct kimage *image);
+#endif
 
 /* Location of the reserved area for the crash kernel */
 struct resource crashk_res = {
@@ -341,6 +343,7 @@ out_free_image:
 	return ret;
 }
 
+#ifdef CONFIG_KEXEC_FILE
 static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
 {
 	struct fd f = fdget(fd);
@@ -612,6 +615,9 @@ out_free_image:
 	kfree(image);
 	return ret;
 }
+#else /* CONFIG_KEXEC_FILE */
+static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
+#endif /* CONFIG_KEXEC_FILE */
 
 static int kimage_is_destination_range(struct kimage *image,
 					unsigned long start,
@@ -1375,6 +1381,7 @@ COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
 }
 #endif
 
+#ifdef CONFIG_KEXEC_FILE
 SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 		unsigned long, cmdline_len, const char __user *, cmdline_ptr,
 		unsigned long, flags)
@@ -1451,6 +1458,8 @@ out:
 	return ret;
 }
 
+#endif /* CONFIG_KEXEC_FILE */
+
 void crash_kexec(struct pt_regs *regs)
 {
 	/* Take the kexec_mutex here to prevent sys_kexec_load
@@ -2006,6 +2015,7 @@ static int __init crash_save_vmcoreinfo_init(void)
 
 subsys_initcall(crash_save_vmcoreinfo_init);
 
+#ifdef CONFIG_KEXEC_FILE
 static int __kexec_add_segment(struct kimage *image, char *buf,
 			       unsigned long bufsz, unsigned long mem,
 			       unsigned long memsz)
@@ -2682,6 +2692,7 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
 
 	return 0;
 }
+#endif /* CONFIG_KEXEC_FILE */
 
 /*
  * Move into place and start executing a preloaded standalone
diff --git a/kernel/resource.c b/kernel/resource.c
index da14b8d0929..60c5a3856ab 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -351,15 +351,12 @@ static int find_next_iomem_res(struct resource *res, char *name,
 	end = res->end;
 	BUG_ON(start >= end);
 
-	read_lock(&resource_lock);
-
-	if (first_level_children_only) {
-		p = iomem_resource.child;
+	if (first_level_children_only)
 		sibling_only = true;
-	} else
-		p = &iomem_resource;
 
-	while ((p = next_resource(p, sibling_only))) {
+	read_lock(&resource_lock);
+
+	for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) {
 		if (p->flags != res->flags)
 			continue;
 		if (name && strcmp(p->name, name))
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index afb04b9b818..b38fb2b9e23 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -626,8 +626,22 @@ int ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu,
 		work = &cpu_buffer->irq_work;
 	}
 
-	work->waiters_pending = true;
 	poll_wait(filp, &work->waiters, poll_table);
+	work->waiters_pending = true;
+	/*
+	 * There's a tight race between setting the waiters_pending and
+	 * checking if the ring buffer is empty.  Once the waiters_pending bit
+	 * is set, the next event will wake the task up, but we can get stuck
+	 * if there's only a single event in.
+	 *
+	 * FIXME: Ideally, we need a memory barrier on the writer side as well,
+	 * but adding a memory barrier to all events will cause too much of a
+	 * performance hit in the fast path.  We only need a memory barrier when
+	 * the buffer goes from empty to having content.  But as this race is
+	 * extremely small, and it's not a problem if another event comes in, we
+	 * will fix it later.
+	 */
+	smp_mb();
 
 	if ((cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer)) ||
 	    (cpu != RING_BUFFER_ALL_CPUS && !ring_buffer_empty_cpu(buffer, cpu)))