[patch 01/22] pollfs: kernel-side API header

[Davi Arnaut <davi@haxent.com.br>]

Add pollfs_fs.h header which contains the kernel-side declarations
and auxiliary macros for type safety checks. Those macros can be
simplified later.

Signed-off-by: Davi E. M. Arnaut <davi@haxent.com.br>

---
 include/linux/pollfs_fs.h |   57 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

Index: linux-2.6/include/linux/pollfs_fs.h
===================================================================
--- /dev/null
+++ linux-2.6/include/linux/pollfs_fs.h
@@ -0,0 +1,57 @@
+/*
+ * pollfs, a naive filesystem for pollable (waitable) files (objects)
+ *
+ * Copyright (C) 2007 Davi E. M. Arnaut
+ *
+ */
+
+#ifndef _LINUX_POLL_FS_H
+#define _LINUX_POLL_FS_H
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <linux/dcache.h>
+#include <linux/fs.h>
+
+#define PFS_CHECK_CALLBACK_1(f, a) (void*)				\
+	(sizeof((f)((typeof(a *))0)))
+
+#define PFS_CHECK_CALLBACK_2(f, a, b) (void*)				\
+	(sizeof((f)((typeof(a *))0, (typeof(b*))0)))
+
+#define PFS_WRITE(func, type, utype)					\
+	(ssize_t (*)(void *, const void __user *))			\
+	(0 ? PFS_CHECK_CALLBACK_2(func, type, utype) : func)
+
+#define PFS_READ(func, type, utype)					\
+	(ssize_t (*)(void *, void __user *))				\
+	(0 ? PFS_CHECK_CALLBACK_2(func, type, utype) : func)
+
+#define PFS_POLL(func, type)						\
+	(int (*)(void *))(0 ? PFS_CHECK_CALLBACK_1(func, type) : func)
+
+#define PFS_RELEASE(func, type)						\
+	(int (*)(void *))(0 ? PFS_CHECK_CALLBACK_1(func, type) : func)
+
+struct pfs_operations {
+	ssize_t (*read)(void *, void __user *);
+	ssize_t (*write)(void *, const void __user *);
+	int (*mmap)(void *, struct vm_area_struct *);
+	int (*poll)(void *);
+	int (*release)(void *);
+	size_t rsize;
+	size_t wsize;
+};
+
+struct pfs_file {
+	void *data;
+	wait_queue_head_t *wait;
+	const struct pfs_operations *fops;
+};
+
+long pfs_open(struct pfs_file *pfs);
+
+#endif	/* __KERNEL __ */
+
+#endif	/* _LINUX_POLLFS_FS_H */

--
-
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