1 files changed, 81 insertions, 22 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 552a8d13bc32..6d7274619bf9 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -165,14 +165,15 @@ blkdev_get_block(struct inode *inode, sector_t iblock,
 }
 
 static ssize_t
-blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-                        loff_t offset, unsigned long nr_segs)
+blkdev_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+                        loff_t offset)
 {
         struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
 
-        return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset,
-                                    nr_segs, blkdev_get_block, NULL, NULL, 0);
+        return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iter,
+                                    offset, blkdev_get_block,
+                                    NULL, NULL, 0);
 }
 
 int __sync_blockdev(struct block_device *bdev, int wait)
@@ -363,6 +364,69 @@ int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 }
 EXPORT_SYMBOL(blkdev_fsync);
 
+/**
+ * bdev_read_page() - Start reading a page from a block device
+ * @bdev: The device to read the page from
+ * @sector: The offset on the device to read the page to (need not be aligned)
+ * @page: The page to read
+ *
+ * On entry, the page should be locked.  It will be unlocked when the page
+ * has been read.  If the block driver implements rw_page synchronously,
+ * that will be true on exit from this function, but it need not be.
+ *
+ * Errors returned by this function are usually "soft", eg out of memory, or
+ * queue full; callers should try a different route to read this page rather
+ * than propagate an error back up the stack.
+ *
+ * Return: negative errno if an error occurs, 0 if submission was successful.
+ */
+int bdev_read_page(struct block_device *bdev, sector_t sector,
+                        struct page *page)
+{
+        const struct block_device_operations *ops = bdev->bd_disk->fops;
+        if (!ops->rw_page)
+                return -EOPNOTSUPP;
+        return ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);
+}
+EXPORT_SYMBOL_GPL(bdev_read_page);
+
+/**
+ * bdev_write_page() - Start writing a page to a block device
+ * @bdev: The device to write the page to
+ * @sector: The offset on the device to write the page to (need not be aligned)
+ * @page: The page to write
+ * @wbc: The writeback_control for the write
+ *
+ * On entry, the page should be locked and not currently under writeback.
+ * On exit, if the write started successfully, the page will be unlocked and
+ * under writeback.  If the write failed already (eg the driver failed to
+ * queue the page to the device), the page will still be locked.  If the
+ * caller is a ->writepage implementation, it will need to unlock the page.
+ *
+ * Errors returned by this function are usually "soft", eg out of memory, or
+ * queue full; callers should try a different route to write this page rather
+ * than propagate an error back up the stack.
+ *
+ * Return: negative errno if an error occurs, 0 if submission was successful.
+ */
+int bdev_write_page(struct block_device *bdev, sector_t sector,
+                        struct page *page, struct writeback_control *wbc)
+{
+        int result;
+        int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE;
+        const struct block_device_operations *ops = bdev->bd_disk->fops;
+        if (!ops->rw_page)
+                return -EOPNOTSUPP;
+        set_page_writeback(page);
+        result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw);
+        if (result)
+                end_page_writeback(page);
+        else
+                unlock_page(page);
+        return result;
+}
+EXPORT_SYMBOL_GPL(bdev_write_page);
+
 /*
  * pseudo-fs
  */
@@ -1508,43 +1572,38 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
  * Does not take i_mutex for the write and thus is not for general purpose
  * use.
  */
-ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
-                         unsigned long nr_segs, loff_t pos)
+ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
         struct file *file = iocb->ki_filp;
         struct blk_plug plug;
         ssize_t ret;
 
-        BUG_ON(iocb->ki_pos != pos);
-
         blk_start_plug(&plug);
-        ret = __generic_file_aio_write(iocb, iov, nr_segs);
+        ret = __generic_file_write_iter(iocb, from);
         if (ret > 0) {
                 ssize_t err;
-
-                err = generic_write_sync(file, pos, ret);
+                err = generic_write_sync(file, iocb->ki_pos - ret, ret);
                 if (err < 0)
                         ret = err;
         }
         blk_finish_plug(&plug);
         return ret;
 }
-EXPORT_SYMBOL_GPL(blkdev_aio_write);
+EXPORT_SYMBOL_GPL(blkdev_write_iter);
 
-static ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov,
-                         unsigned long nr_segs, loff_t pos)
+static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
         struct file *file = iocb->ki_filp;
         struct inode *bd_inode = file->f_mapping->host;
         loff_t size = i_size_read(bd_inode);
+        loff_t pos = iocb->ki_pos;
 
         if (pos >= size)
                 return 0;
 
         size -= pos;
-        if (size < iocb->ki_nbytes)
-                nr_segs = iov_shorten((struct iovec *)iov, nr_segs, size);
-        return generic_file_aio_read(iocb, iov, nr_segs, pos);
+        iov_iter_truncate(to, size);
+        return generic_file_read_iter(iocb, to);
 }
 
 /*
@@ -1576,10 +1635,10 @@ const struct file_operations def_blk_fops = {
         .open           = blkdev_open,
         .release        = blkdev_close,
         .llseek         = block_llseek,
-        .read           = do_sync_read,
-        .write          = do_sync_write,
-        .aio_read       = blkdev_aio_read,
-        .aio_write      = blkdev_aio_write,
+        .read           = new_sync_read,
+        .write          = new_sync_write,
+        .read_iter      = blkdev_read_iter,
+        .write_iter     = blkdev_write_iter,
         .mmap           = generic_file_mmap,
         .fsync          = blkdev_fsync,
         .unlocked_ioctl = block_ioctl,
@@ -1587,7 +1646,7 @@ const struct file_operations def_blk_fops = {
         .compat_ioctl   = compat_blkdev_ioctl,
 #endif
         .splice_read    = generic_file_splice_read,
-        .splice_write   = generic_file_splice_write,
+        .splice_write   = iter_file_splice_write,
 };
 
 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)