Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 26 insertions, 25 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 9ddb9fc7d923..eba6e4f621ce 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -77,7 +77,7 @@ EXPORT_SYMBOL(__lock_buffer);
 void unlock_buffer(struct buffer_head *bh)
 {
 	clear_bit_unlock(BH_Lock, &bh->b_state);
-	smp_mb__after_clear_bit();
+	smp_mb__after_atomic();
 	wake_up_bit(&bh->b_state, BH_Lock);
 }
 EXPORT_SYMBOL(unlock_buffer);
@@ -227,7 +227,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t block)
 	int all_mapped = 1;
 
 	index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits);
-	page = find_get_page(bd_mapping, index);
+	page = find_get_page_flags(bd_mapping, index, FGP_ACCESSED);
 	if (!page)
 		goto out;
 
@@ -1366,12 +1366,13 @@ __find_get_block(struct block_device *bdev, sector_t block, unsigned size)
 	struct buffer_head *bh = lookup_bh_lru(bdev, block, size);
 
 	if (bh == NULL) {
+		/* __find_get_block_slow will mark the page accessed */
 		bh = __find_get_block_slow(bdev, block);
 		if (bh)
 			bh_lru_install(bh);
-	}
-	if (bh)
+	} else
 		touch_buffer(bh);
+
 	return bh;
 }
 EXPORT_SYMBOL(__find_get_block);
@@ -1483,16 +1484,27 @@ EXPORT_SYMBOL(set_bh_page);
 /*
  * Called when truncating a buffer on a page completely.
  */
+
+/* Bits that are cleared during an invalidate */
+#define BUFFER_FLAGS_DISCARD \
+	(1 << BH_Mapped | 1 << BH_New | 1 << BH_Req | \
+	 1 << BH_Delay | 1 << BH_Unwritten)
+
 static void discard_buffer(struct buffer_head * bh)
 {
+	unsigned long b_state, b_state_old;
+
 	lock_buffer(bh);
 	clear_buffer_dirty(bh);
 	bh->b_bdev = NULL;
-	clear_buffer_mapped(bh);
-	clear_buffer_req(bh);
-	clear_buffer_new(bh);
-	clear_buffer_delay(bh);
-	clear_buffer_unwritten(bh);
+	b_state = bh->b_state;
+	for (;;) {
+		b_state_old = cmpxchg(&bh->b_state, b_state,
+				      (b_state & ~BUFFER_FLAGS_DISCARD));
+		if (b_state_old == b_state)
+			break;
+		b_state = b_state_old;
+	}
 	unlock_buffer(bh);
 }
 
@@ -2879,10 +2891,9 @@ EXPORT_SYMBOL(block_truncate_page);
 
 /*
  * The generic ->writepage function for buffer-backed address_spaces
- * this form passes in the end_io handler used to finish the IO.
  */
-int block_write_full_page_endio(struct page *page, get_block_t *get_block,
-			struct writeback_control *wbc, bh_end_io_t *handler)
+int block_write_full_page(struct page *page, get_block_t *get_block,
+			struct writeback_control *wbc)
 {
 	struct inode * const inode = page->mapping->host;
 	loff_t i_size = i_size_read(inode);
@@ -2892,7 +2903,7 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
 	/* Is the page fully inside i_size? */
 	if (page->index < end_index)
 		return __block_write_full_page(inode, page, get_block, wbc,
-					       handler);
+					       end_buffer_async_write);
 
 	/* Is the page fully outside i_size? (truncate in progress) */
 	offset = i_size & (PAGE_CACHE_SIZE-1);
@@ -2915,18 +2926,8 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
 	 * writes to that region are not written out to the file."
 	 */
 	zero_user_segment(page, offset, PAGE_CACHE_SIZE);
-	return __block_write_full_page(inode, page, get_block, wbc, handler);
-}
-EXPORT_SYMBOL(block_write_full_page_endio);
-
-/*
- * The generic ->writepage function for buffer-backed address_spaces
- */
-int block_write_full_page(struct page *page, get_block_t *get_block,
-			struct writeback_control *wbc)
-{
-	return block_write_full_page_endio(page, get_block, wbc,
-					   end_buffer_async_write);
+	return __block_write_full_page(inode, page, get_block, wbc,
+							end_buffer_async_write);
 }
 EXPORT_SYMBOL(block_write_full_page);