[PATCH] uml: use host AIO support

This patch makes UML use host AIO support when it (and
/usr/include/linux/aio_abi.h) are present.  This is only the support, with no
consumers - a consumer is coming in the next patch.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/include/aio.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2004 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef AIO_H__
+#define AIO_H__
+
+enum aio_type { AIO_READ, AIO_WRITE, AIO_MMAP };
+
+struct aio_thread_reply {
+	void *data;
+	int err;
+};
+
+struct aio_context {
+	int reply_fd;
+	struct aio_context *next;
+};
+
+#define INIT_AIO_CONTEXT { .reply_fd	= -1, \
+			   .next	= NULL }
+
+extern int submit_aio(enum aio_type type, int fd, char *buf, int len,
+		      unsigned long long offset, int reply_fd,
+                      struct aio_context *aio);
+
+#endif

arch/um/include/init.h

@@ -111,7 +111,15 @@ extern struct uml_param __uml_setup_start, __uml_setup_end;
 
 #ifndef __KERNEL__
 
-#define __initcall(fn) static initcall_t __initcall_##fn __init_call = fn
+#define __define_initcall(level,fn) \
+	static initcall_t __initcall_##fn __attribute_used__ \
+	__attribute__((__section__(".initcall" level ".init"))) = fn
+
+/* Userspace initcalls shouldn't depend on anything in the kernel, so we'll
+ * make them run first.
+ */
+#define __initcall(fn) __define_initcall("1", fn)
+
 #define __exitcall(fn) static exitcall_t __exitcall_##fn __exit_call = fn
 
 #define __init_call __attribute__ ((unused,__section__ (".initcall.init")))

arch/um/include/irq_kern.h

@@ -7,12 +7,15 @@
 #define __IRQ_KERN_H__
 
 #include "linux/interrupt.h"
+#include "asm/ptrace.h"
 
 extern int um_request_irq(unsigned int irq, int fd, int type,
 			  irqreturn_t (*handler)(int, void *,
 						 struct pt_regs *),
 			  unsigned long irqflags,  const char * devname,
 			  void *dev_id);
+extern int init_aio_irq(int irq, char *name,
+			irqreturn_t (*handler)(int, void *, struct pt_regs *));
 
 #endif
 

arch/um/kernel/irq.c

@@ -31,7 +31,7 @@
 #include "kern_util.h"
 #include "irq_user.h"
 #include "irq_kern.h"
-
+#include "os.h"
 
 /*
  * Generic, controller-independent functions:
@@ -168,13 +168,32 @@ void __init init_IRQ(void)
 	}
 }
 
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
+int init_aio_irq(int irq, char *name, irqreturn_t (*handler)(int, void *,
+							     struct pt_regs *))
+{
+	int fds[2], err;
+
+	err = os_pipe(fds, 1, 1);
+	if(err){
+		printk("init_aio_irq - os_pipe failed, err = %d\n", -err);
+		goto out;
+	}
+
+	err = um_request_irq(irq, fds[0], IRQ_READ, handler,
+			     SA_INTERRUPT | SA_SAMPLE_RANDOM, name,
+			     (void *) (long) fds[0]);
+	if(err){
+		printk("init_aio_irq - : um_request_irq failed, err = %d\n",
+		       err);
+		goto out_close;
+	}
+
+	err = fds[1];
+	goto out;
+
+ out_close:
+	os_close_file(fds[0]);
+	os_close_file(fds[1]);
+ out:
+	return(err);
+}

arch/um/os-Linux/Makefile

@@ -3,11 +3,15 @@
 # Licensed under the GPL
 #
 
-obj-y = elf_aux.o file.o process.o signal.o time.o tty.o user_syms.o drivers/ \
-	sys-$(SUBARCH)/
+obj-y = aio.o elf_aux.o file.o process.o signal.o time.o tty.o user_syms.o \
+	drivers/ sys-$(SUBARCH)/
 
-USER_OBJS := elf_aux.o file.o process.o signal.o time.o tty.o
+USER_OBJS := aio.o elf_aux.o file.o process.o signal.o time.o tty.o
 
 CFLAGS_user_syms.o += -DSUBARCH_$(SUBARCH)
 
+HAVE_AIO_ABI := $(shell [ -r /usr/include/linux/aio_abi.h ] && \
+	echo -DHAVE_AIO_ABI )
+CFLAGS_aio.o += $(HAVE_AIO_ABI)
+
 include arch/um/scripts/Makefile.rules