Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "iov_iter cleanups and fixes.

  There are followups, but this is what had sat in -next this cycle. IMO
  the macro forest in there became much thinner and easier to follow..."

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
  csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller
  clean up copy_mc_pipe_to_iter()
  pipe_zero(): we don't need no stinkin' kmap_atomic()...
  iov_iter: clean csum_and_copy_...() primitives up a bit
  copy_page_from_iter(): don't need kmap_atomic() for kvec/bvec cases
  copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases
  iterate_xarray(): only of the first iteration we might get offset != 0
  pull handling of ->iov_offset into iterate_{iovec,bvec,xarray}
  iov_iter: make iterator callbacks use base and len instead of iovec
  iov_iter: make the amount already copied available to iterator callbacks
  iov_iter: get rid of separate bvec and xarray callbacks
  iov_iter: teach iterate_{bvec,xarray}() about possible short copies
  iterate_bvec(): expand bvec.h macro forest, massage a bit
  iov_iter: unify iterate_iovec and iterate_kvec
  iov_iter: massage iterate_iovec and iterate_kvec to logics similar to iterate_bvec
  iterate_and_advance(): get rid of magic in case when n is 0
  csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter()
  iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant
  [xarray] iov_iter_npages(): just use DIV_ROUND_UP()
  iov_iter_npages(): don't bother with iterate_all_kinds()
  ...

2 files changed, 42 insertions, 38 deletions

diff --git a/include/linux/uio.h b/include/linux/uio.h
index d3ec87706d75..82c3c3e819e0 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -19,21 +19,17 @@ struct kvec {
 
 enum iter_type {
 	/* iter types */
-	ITER_IOVEC = 4,
-	ITER_KVEC = 8,
-	ITER_BVEC = 16,
-	ITER_PIPE = 32,
-	ITER_DISCARD = 64,
-	ITER_XARRAY = 128,
+	ITER_IOVEC,
+	ITER_KVEC,
+	ITER_BVEC,
+	ITER_PIPE,
+	ITER_XARRAY,
+	ITER_DISCARD,
 };
 
 struct iov_iter {
-	/*
-	 * Bit 0 is the read/write bit, set if we're writing.
-	 * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and
-	 * the caller isn't expecting to drop a page reference when done.
-	 */
-	unsigned int type;
+	u8 iter_type;
+	bool data_source;
 	size_t iov_offset;
 	size_t count;
 	union {
@@ -55,7 +51,7 @@ struct iov_iter {
 
 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
 {
-	return i->type & ~(READ | WRITE);
+	return i->iter_type;
 }
 
 static inline bool iter_is_iovec(const struct iov_iter *i)
@@ -90,7 +86,7 @@ static inline bool iov_iter_is_xarray(const struct iov_iter *i)
 
 static inline unsigned char iov_iter_rw(const struct iov_iter *i)
 {
-	return i->type & (READ | WRITE);
+	return i->data_source ? WRITE : READ;
 }
 
 /*
@@ -119,11 +115,11 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
 	};
 }
 
-size_t iov_iter_copy_from_user_atomic(struct page *page,
-		struct iov_iter *i, unsigned long offset, size_t bytes);
+size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,
+				  size_t bytes, struct iov_iter *i);
 void iov_iter_advance(struct iov_iter *i, size_t bytes);
 void iov_iter_revert(struct iov_iter *i, size_t bytes);
-int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
+int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes);
 size_t iov_iter_single_seg_count(const struct iov_iter *i);
 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 			 struct iov_iter *i);
@@ -132,9 +128,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
 
 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
-bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
-bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
 
 static __always_inline __must_check
 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
@@ -157,10 +151,11 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 static __always_inline __must_check
 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
 {
-	if (unlikely(!check_copy_size(addr, bytes, false)))
-		return false;
-	else
-		return _copy_from_iter_full(addr, bytes, i);
+	size_t copied = copy_from_iter(addr, bytes, i);
+	if (likely(copied == bytes))
+		return true;
+	iov_iter_revert(i, copied);
+	return false;
 }
 
 static __always_inline __must_check
@@ -175,10 +170,11 @@ size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
 static __always_inline __must_check
 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
-	if (unlikely(!check_copy_size(addr, bytes, false)))
-		return false;
-	else
-		return _copy_from_iter_full_nocache(addr, bytes, i);
+	size_t copied = copy_from_iter_nocache(addr, bytes, i);
+	if (likely(copied == bytes))
+		return true;
+	iov_iter_revert(i, copied);
+	return false;
 }
 
 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
@@ -278,7 +274,17 @@ struct csum_state {
 
 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
-bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+
+static __always_inline __must_check
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
+				  __wsum *csum, struct iov_iter *i)
+{
+	size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
+	if (likely(copied == bytes))
+		return true;
+	iov_iter_revert(i, copied);
+	return false;
+}
 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
 		struct iov_iter *i);
 
@@ -294,8 +300,4 @@ ssize_t __import_iovec(int type, const struct iovec __user *uvec,
 int import_single_range(int type, void __user *buf, size_t len,
 		 struct iovec *iov, struct iov_iter *i);
 
-int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
-			    int (*f)(struct kvec *vec, void *context),
-			    void *context);
-
 #endif
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 0d05b9e8690b..5b96d5bd6e54 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -80,16 +80,18 @@ static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
 	return csum16_add(csum, ~addend);
 }
 
-static inline __wsum
-csum_block_add(__wsum csum, __wsum csum2, int offset)
+static inline __wsum csum_shift(__wsum sum, int offset)
 {
-	u32 sum = (__force u32)csum2;
-
 	/* rotate sum to align it with a 16b boundary */
 	if (offset & 1)
-		sum = ror32(sum, 8);
+		return (__force __wsum)ror32((__force u32)sum, 8);
+	return sum;
+}
 
-	return csum_add(csum, (__force __wsum)sum);
+static inline __wsum
+csum_block_add(__wsum csum, __wsum csum2, int offset)
+{
+	return csum_add(csum, csum_shift(csum2, offset));
 }
 
 static inline __wsum