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

Pull iov_iter cleanups from Al Viro.

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fold checks into iterate_and_advance()
  rw_verify_area(): saner calling conventions
  aio: remove a pointless assignment

fs/aio.c

@@ -1447,8 +1447,6 @@ static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode,
 			return ret;
 		}
 
-		len = ret;
-
 		if (rw == WRITE)
 			file_start_write(file);
 

fs/read_write.c

@@ -398,11 +398,6 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
 }
 EXPORT_SYMBOL(vfs_iter_write);
 
-/*
- * rw_verify_area doesn't like huge counts. We limit
- * them to something that fits in "int" so that others
- * won't have to do range checks all the time.
- */
 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
 {
 	struct inode *inode;
@@ -429,11 +424,8 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
 		if (retval < 0)
 			return retval;
 	}
-	retval = security_file_permission(file,
+	return security_file_permission(file,
 				read_write == READ ? MAY_READ : MAY_WRITE);
-	if (retval)
-		return retval;
-	return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
 }
 
 static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
@@ -477,8 +469,9 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
 		return -EFAULT;
 
 	ret = rw_verify_area(READ, file, pos, count);
-	if (ret >= 0) {
-		count = ret;
+	if (!ret) {
+		if (count > MAX_RW_COUNT)
+			count =  MAX_RW_COUNT;
 		ret = __vfs_read(file, buf, count, pos);
 		if (ret > 0) {
 			fsnotify_access(file);
@@ -560,8 +553,9 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
 		return -EFAULT;
 
 	ret = rw_verify_area(WRITE, file, pos, count);
-	if (ret >= 0) {
-		count = ret;
+	if (!ret) {
+		if (count > MAX_RW_COUNT)
+			count =  MAX_RW_COUNT;
 		file_start_write(file);
 		ret = __vfs_write(file, buf, count, pos);
 		if (ret > 0) {
@@ -1315,7 +1309,8 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 	retval = rw_verify_area(READ, in.file, &pos, count);
 	if (retval < 0)
 		goto fput_in;
-	count = retval;
+	if (count > MAX_RW_COUNT)
+		count =  MAX_RW_COUNT;
 
 	/*
 	 * Get output file, and verify that it is ok..
@@ -1333,7 +1328,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 	retval = rw_verify_area(WRITE, out.file, &out_pos, count);
 	if (retval < 0)
 		goto fput_out;
-	count = retval;
 
 	if (!max)
 		max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
@@ -1477,11 +1471,12 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
 	if (flags != 0)
 		return -EINVAL;
 
-	/* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT  */
 	ret = rw_verify_area(READ, file_in, &pos_in, len);
-	if (ret >= 0)
+	if (unlikely(ret))
+		return ret;
+
 	ret = rw_verify_area(WRITE, file_out, &pos_out, len);
-	if (ret < 0)
+	if (unlikely(ret))
 		return ret;
 
 	if (!(file_in->f_mode & FMODE_READ) ||

lib/iov_iter.c

@@ -99,6 +99,9 @@
 }
 
 #define iterate_and_advance(i, n, v, I, B, K) {			\
+	if (unlikely(i->count < n))				\
+		n = i->count;					\
+	if (n) {						\
 		size_t skip = i->iov_offset;			\
 		if (unlikely(i->type & ITER_BVEC)) {		\
 			const struct bio_vec *bvec;		\
@@ -133,6 +136,7 @@
 		}						\
 		i->count -= n;					\
 		i->iov_offset = skip;				\
+	}							\
 }
 
 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
@@ -386,12 +390,6 @@ static void memzero_page(struct page *page, size_t offset, size_t len)
 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
 	const char *from = addr;
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
 	iterate_and_advance(i, bytes, v,
 		__copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
 			       v.iov_len),
@@ -407,12 +405,6 @@ EXPORT_SYMBOL(copy_to_iter);
 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
 	iterate_and_advance(i, bytes, v,
 		__copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
 				 v.iov_len),
@@ -428,12 +420,6 @@ EXPORT_SYMBOL(copy_from_iter);
 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
 	iterate_and_advance(i, bytes, v,
 		__copy_from_user_nocache((to += v.iov_len) - v.iov_len,
 					 v.iov_base, v.iov_len),
@@ -474,12 +460,6 @@ EXPORT_SYMBOL(copy_page_from_iter);
 
 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
 {
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
 	iterate_and_advance(i, bytes, v,
 		__clear_user(v.iov_base, v.iov_len),
 		memzero_page(v.bv_page, v.bv_offset, v.bv_len),
@@ -685,12 +665,6 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
 	char *to = addr;
 	__wsum sum, next;
 	size_t off = 0;
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
 	sum = *csum;
 	iterate_and_advance(i, bytes, v, ({
 		int err = 0;
@@ -729,12 +703,6 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
 	const char *from = addr;
 	__wsum sum, next;
 	size_t off = 0;
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
 	sum = *csum;
 	iterate_and_advance(i, bytes, v, ({
 		int err = 0;