Merge branch 'akpm' (final batch from Andrew)

Merge third patch-bumb from Andrew Morton:
 "This wraps me up for -rc1.
   - Lots of misc stuff and things which were deferred/missed from
     patchbombings 1 & 2.
   - ocfs2 things
   - lib/scatterlist
   - hfsplus
   - fatfs
   - documentation
   - signals
   - procfs
   - lockdep
   - coredump
   - seqfile core
   - kexec
   - Tejun's large IDR tree reworkings
   - ipmi
   - partitions
   - nbd
   - random() things
   - kfifo
   - tools/testing/selftests updates
   - Sasha's large and pointless hlist cleanup"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (163 commits)
  hlist: drop the node parameter from iterators
  kcmp: make it depend on CHECKPOINT_RESTORE
  selftests: add a simple doc
  tools/testing/selftests/Makefile: rearrange targets
  selftests/efivarfs: add create-read test
  selftests/efivarfs: add empty file creation test
  selftests: add tests for efivarfs
  kfifo: fix kfifo_alloc() and kfifo_init()
  kfifo: move kfifo.c from kernel/ to lib/
  arch Kconfig: centralise CONFIG_ARCH_NO_VIRT_TO_BUS
  w1: add support for DS2413 Dual Channel Addressable Switch
  memstick: move the dereference below the NULL test
  drivers/pps/clients/pps-gpio.c: use devm_kzalloc
  Documentation/DMA-API-HOWTO.txt: fix typo
  include/linux/eventfd.h: fix incorrect filename is a comment
  mtd: mtd_stresstest: use prandom_bytes()
  mtd: mtd_subpagetest: convert to use prandom library
  mtd: mtd_speedtest: use prandom_bytes
  mtd: mtd_pagetest: convert to use prandom library
  mtd: mtd_oobtest: convert to use prandom library
  ...

1 files changed, 38 insertions, 3 deletions

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 4bd6c06eb28..2d8bdaef961 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -231,6 +231,41 @@ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
  */
 #define SG_MAX_SINGLE_ALLOC		(PAGE_SIZE / sizeof(struct scatterlist))
 
+/*
+ * sg page iterator
+ *
+ * Iterates over sg entries page-by-page.  On each successful iteration,
+ * @piter->page points to the current page, @piter->sg to the sg holding this
+ * page and @piter->sg_pgoffset to the page's page offset within the sg. The
+ * iteration will stop either when a maximum number of sg entries was reached
+ * or a terminating sg (sg_last(sg) == true) was reached.
+ */
+struct sg_page_iter {
+	struct page		*page;		/* current page */
+	struct scatterlist	*sg;		/* sg holding the page */
+	unsigned int		sg_pgoffset;	/* page offset within the sg */
+
+	/* these are internal states, keep away */
+	unsigned int		__nents;	/* remaining sg entries */
+	int			__pg_advance;	/* nr pages to advance at the
+						 * next step */
+};
+
+bool __sg_page_iter_next(struct sg_page_iter *piter);
+void __sg_page_iter_start(struct sg_page_iter *piter,
+			  struct scatterlist *sglist, unsigned int nents,
+			  unsigned long pgoffset);
+
+/**
+ * for_each_sg_page - iterate over the pages of the given sg list
+ * @sglist:	sglist to iterate over
+ * @piter:	page iterator to hold current page, sg, sg_pgoffset
+ * @nents:	maximum number of sg entries to iterate over
+ * @pgoffset:	starting page offset
+ */
+#define for_each_sg_page(sglist, piter, nents, pgoffset)		   \
+	for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \
+	     __sg_page_iter_next(piter);)
 
 /*
  * Mapping sg iterator
@@ -258,11 +293,11 @@ struct sg_mapping_iter {
 	void			*addr;		/* pointer to the mapped area */
 	size_t			length;		/* length of the mapped area */
 	size_t			consumed;	/* number of consumed bytes */
+	struct sg_page_iter	piter;		/* page iterator */
 
 	/* these are internal states, keep away */
-	struct scatterlist	*__sg;		/* current entry */
-	unsigned int		__nents;	/* nr of remaining entries */
-	unsigned int		__offset;	/* offset within sg */
+	unsigned int		__offset;	/* offset within page */
+	unsigned int		__remaining;	/* remaining bytes on page */
 	unsigned int		__flags;
 };