6 files changed, 73 insertions, 29 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 4060691e78f7..8e1b68786d66 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -333,6 +333,52 @@ out_putf:
 }
 #endif
 
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+        struct kiocb kiocb;
+        ssize_t ret;
+
+        if (!file->f_op->read_iter)
+                return -EINVAL;
+
+        init_sync_kiocb(&kiocb, file);
+        kiocb.ki_pos = *ppos;
+        kiocb.ki_nbytes = iov_iter_count(iter);
+
+        iter->type |= READ;
+        ret = file->f_op->read_iter(&kiocb, iter);
+        if (ret == -EIOCBQUEUED)
+                ret = wait_on_sync_kiocb(&kiocb);
+
+        if (ret > 0)
+                *ppos = kiocb.ki_pos;
+        return ret;
+}
+EXPORT_SYMBOL(vfs_iter_read);
+
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+        struct kiocb kiocb;
+        ssize_t ret;
+
+        if (!file->f_op->write_iter)
+                return -EINVAL;
+
+        init_sync_kiocb(&kiocb, file);
+        kiocb.ki_pos = *ppos;
+        kiocb.ki_nbytes = iov_iter_count(iter);
+
+        iter->type |= WRITE;
+        ret = file->f_op->write_iter(&kiocb, iter);
+        if (ret == -EIOCBQUEUED)
+                ret = wait_on_sync_kiocb(&kiocb);
+
+        if (ret > 0)
+                *ppos = kiocb.ki_pos;
+        return ret;
+}
+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
diff --git a/fs/splice.c b/fs/splice.c
index 75c6058eabf2..7968da96bebb 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -961,7 +961,6 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
         splice_from_pipe_begin(&sd);
         while (sd.total_len) {
                 struct iov_iter from;
-                struct kiocb kiocb;
                 size_t left;
                 int n, idx;
 
@@ -1005,29 +1004,15 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
                         left -= this_len;
                 }
 
-                /* ... iov_iter */
-                from.type = ITER_BVEC | WRITE;
-                from.bvec = array;
-                from.nr_segs = n;
-                from.count = sd.total_len - left;
-                from.iov_offset = 0;
-
-                /* ... and iocb */
-                init_sync_kiocb(&kiocb, out);
-                kiocb.ki_pos = sd.pos;
-                kiocb.ki_nbytes = sd.total_len - left;
-
-                /* now, send it */
-                ret = out->f_op->write_iter(&kiocb, &from);
-                if (-EIOCBQUEUED == ret)
-                        ret = wait_on_sync_kiocb(&kiocb);
-
+                iov_iter_bvec(&from, ITER_BVEC | WRITE, array, n,
+                              sd.total_len - left);
+                ret = vfs_iter_write(out, &from, &sd.pos);
                 if (ret <= 0)
                         break;
 
                 sd.num_spliced += ret;
                 sd.total_len -= ret;
-                *ppos = sd.pos = kiocb.ki_pos;
+                *ppos = sd.pos;
 
                 /* dismiss the fully eaten buffers, adjust the partial one */
                 while (ret) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a9250b2a11ba..0b5b146d0490 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2548,6 +2548,9 @@ extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t l
 extern ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
 extern ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
 
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos);
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos);
+
 /* fs/block_dev.c */
 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 3e0cb4ea3905..07a022641996 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -88,7 +88,9 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *);
 unsigned long iov_iter_alignment(const struct iov_iter *i);
 void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
                         unsigned long nr_segs, size_t count);
-void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *iov,
+void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
+                        unsigned long nr_segs, size_t count);
+void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
                         unsigned long nr_segs, size_t count);
 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
                         size_t maxsize, unsigned maxpages, size_t *start);
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index a1599ca4ab0e..827732047da1 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -501,18 +501,31 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i)
 EXPORT_SYMBOL(iov_iter_single_seg_count);
 
 void iov_iter_kvec(struct iov_iter *i, int direction,
-                        const struct kvec *iov, unsigned long nr_segs,
+                        const struct kvec *kvec, unsigned long nr_segs,
                         size_t count)
 {
         BUG_ON(!(direction & ITER_KVEC));
         i->type = direction;
-        i->kvec = (struct kvec *)iov;
+        i->kvec = kvec;
         i->nr_segs = nr_segs;
         i->iov_offset = 0;
         i->count = count;
 }
 EXPORT_SYMBOL(iov_iter_kvec);
 
+void iov_iter_bvec(struct iov_iter *i, int direction,
+                        const struct bio_vec *bvec, unsigned long nr_segs,
+                        size_t count)
+{
+        BUG_ON(!(direction & ITER_BVEC));
+        i->type = direction;
+        i->bvec = bvec;
+        i->nr_segs = nr_segs;
+        i->iov_offset = 0;
+        i->count = count;
+}
+EXPORT_SYMBOL(iov_iter_bvec);
+
 unsigned long iov_iter_alignment(const struct iov_iter *i)
 {
         unsigned long res = 0;
diff --git a/mm/page_io.c b/mm/page_io.c
index 955db8b0d497..e6045804c8d8 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -269,14 +269,9 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
                         .bv_len  = PAGE_SIZE,
                         .bv_offset = 0
                 };
-                struct iov_iter from = {
-                        .type = ITER_BVEC | WRITE,
-                        .count = PAGE_SIZE,
-                        .iov_offset = 0,
-                        .nr_segs = 1,
-                };
-                from.bvec = &bv;        /* older gcc versions are broken */
+                struct iov_iter from;
 
+                iov_iter_bvec(&from, ITER_BVEC | WRITE, &bv, 1, PAGE_SIZE);
                 init_sync_kiocb(&kiocb, swap_file);
                 kiocb.ki_pos = page_file_offset(page);
                 kiocb.ki_nbytes = PAGE_SIZE;