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authorChristoph Hellwig <hch@lst.de>2015-01-25 23:11:59 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-01-29 08:13:13 +0300
commitdbe4e192a234cd6133d86fffb965d0f032c12ccc (patch)
treee5b5bbc9b22a289ec33fbc808f7e81d926caec06 /fs/read_write.c
parent05afcb77eb4713f46e7ebaa3cb54bc465c5d516e (diff)
downloadlinux-dbe4e192a234cd6133d86fffb965d0f032c12ccc.tar.xz
fs: add vfs_iter_{read,write} helpers
Simple helpers that pass an arbitrary iov_iter to filesystems. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index c0805c93b6fa..ab4f26a7d5cb 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