Merge branch 'linus' into core/rcu

Conflicts:
	fs/fs-writeback.c

Merge reason: Resolve the conflict

Note, i picked the version from Linus's tree, which effectively reverts
the fs-writeback.c bits of:

  b97181f: fs: remove all rcu head initializations, except on_stack initializations

As the upstream changes to this file changed this code heavily and the
first attempt to resolve the conflict resulted in a non-booting kernel.
It's safer to re-try this portion of the commit cleanly.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 21 insertions, 18 deletions

diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c
index bfc2abafac44..67a84d8f118d 100644
--- a/arch/powerpc/kernel/rtas_flash.c
+++ b/arch/powerpc/kernel/rtas_flash.c
@@ -94,12 +94,8 @@ struct flash_block_list {
 	struct flash_block_list *next;
 	struct flash_block blocks[FLASH_BLOCKS_PER_NODE];
 };
-struct flash_block_list_header { /* just the header of flash_block_list */
-	unsigned long num_blocks;
-	struct flash_block_list *next;
-};
 
-static struct flash_block_list_header rtas_firmware_flash_list = {0, NULL};
+static struct flash_block_list *rtas_firmware_flash_list;
 
 /* Use slab cache to guarantee 4k alignment */
 static struct kmem_cache *flash_block_cache = NULL;
@@ -108,13 +104,14 @@ static struct kmem_cache *flash_block_cache = NULL;
 
 /* Local copy of the flash block list.
  * We only allow one open of the flash proc file and create this
- * list as we go.  This list will be put in the
- * rtas_firmware_flash_list var once it is fully read.
+ * list as we go.  The rtas_firmware_flash_list varable will be
+ * set once the data is fully read.
  *
  * For convenience as we build the list we use virtual addrs,
  * we do not fill in the version number, and the length field
  * is treated as the number of entries currently in the block
- * (i.e. not a byte count).  This is all fixed on release.
+ * (i.e. not a byte count).  This is all fixed when calling 
+ * the flash routine.
  */
 
 /* Status int must be first member of struct */
@@ -201,16 +198,16 @@ static int rtas_flash_release(struct inode *inode, struct file *file)
 	if (uf->flist) {    
 		/* File was opened in write mode for a new flash attempt */
 		/* Clear saved list */
-		if (rtas_firmware_flash_list.next) {
-			free_flash_list(rtas_firmware_flash_list.next);
-			rtas_firmware_flash_list.next = NULL;
+		if (rtas_firmware_flash_list) {
+			free_flash_list(rtas_firmware_flash_list);
+			rtas_firmware_flash_list = NULL;
 		}
 
 		if (uf->status != FLASH_AUTH)  
 			uf->status = flash_list_valid(uf->flist);
 
 		if (uf->status == FLASH_IMG_READY) 
-			rtas_firmware_flash_list.next = uf->flist;
+			rtas_firmware_flash_list = uf->flist;
 		else
 			free_flash_list(uf->flist);
 
@@ -593,7 +590,7 @@ static void rtas_flash_firmware(int reboot_type)
 	unsigned long rtas_block_list;
 	int i, status, update_token;
 
-	if (rtas_firmware_flash_list.next == NULL)
+	if (rtas_firmware_flash_list == NULL)
 		return;		/* nothing to do */
 
 	if (reboot_type != SYS_RESTART) {
@@ -610,20 +607,25 @@ static void rtas_flash_firmware(int reboot_type)
 		return;
 	}
 
-	/* NOTE: the "first" block list is a global var with no data
-	 * blocks in the kernel data segment.  We do this because
-	 * we want to ensure this block_list addr is under 4GB.
+	/*
+	 * NOTE: the "first" block must be under 4GB, so we create
+	 * an entry with no data blocks in the reserved buffer in
+	 * the kernel data segment.
 	 */
-	rtas_firmware_flash_list.num_blocks = 0;
-	flist = (struct flash_block_list *)&rtas_firmware_flash_list;
+	spin_lock(&rtas_data_buf_lock);
+	flist = (struct flash_block_list *)&rtas_data_buf[0];
+	flist->num_blocks = 0;
+	flist->next = rtas_firmware_flash_list;
 	rtas_block_list = virt_to_abs(flist);
 	if (rtas_block_list >= 4UL*1024*1024*1024) {
 		printk(KERN_ALERT "FLASH: kernel bug...flash list header addr above 4GB\n");
+		spin_unlock(&rtas_data_buf_lock);
 		return;
 	}
 
 	printk(KERN_ALERT "FLASH: preparing saved firmware image for flash\n");
 	/* Update the block_list in place. */
+	rtas_firmware_flash_list = NULL; /* too hard to backout on error */
 	image_size = 0;
 	for (f = flist; f; f = next) {
 		/* Translate data addrs to absolute */
@@ -664,6 +666,7 @@ static void rtas_flash_firmware(int reboot_type)
 		printk(KERN_ALERT "FLASH: unknown flash return code %d\n", status);
 		break;
 	}
+	spin_unlock(&rtas_data_buf_lock);
 }
 
 static void remove_flash_pde(struct proc_dir_entry *dp)