um: remove unused AIO code

/*

 * 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

# Don't instrument UML-specific code

KCOV_INSTRUMENT                := n

obj-y = aio.o execvp.o file.o helper.o irq.o main.o mem.o process.o \

obj-y = execvp.o file.o helper.o irq.o main.o mem.o process.o \

	registers.o sigio.o signal.o start_up.o time.o tty.o \

	umid.o user_syms.o util.o drivers/ skas/

obj-$(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) += elf_aux.o

USER_OBJS := $(user-objs-y) aio.o elf_aux.o execvp.o file.o helper.o irq.o \

USER_OBJS := $(user-objs-y) elf_aux.o execvp.o file.o helper.o irq.o \

	main.o mem.o process.o registers.o sigio.o signal.o start_up.o time.o \

	tty.o umid.o util.o

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

/*

 * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)

 * Licensed under the GPL

 */

#include <unistd.h>

#include <sched.h>

#include <signal.h>

#include <errno.h>

#include <sys/time.h>

#include <asm/unistd.h>

#include <aio.h>

#include <init.h>

#include <kern_util.h>

#include <os.h>

struct aio_thread_req {

	enum aio_type type;

	int io_fd;

	unsigned long long offset;

	char *buf;

	int len;

	struct aio_context *aio;

};

#if defined(HAVE_AIO_ABI)

#include <linux/aio_abi.h>

/*

 * If we have the headers, we are going to build with AIO enabled.

 * If we don't have aio in libc, we define the necessary stubs here.

 */

#if !defined(HAVE_AIO_LIBC)

static long io_setup(int n, aio_context_t *ctxp)

{

	return syscall(__NR_io_setup, n, ctxp);

}

static long io_submit(aio_context_t ctx, long nr, struct iocb **iocbpp)

{

	return syscall(__NR_io_submit, ctx, nr, iocbpp);

}

static long io_getevents(aio_context_t ctx_id, long min_nr, long nr,

			 struct io_event *events, struct timespec *timeout)

{

	return syscall(__NR_io_getevents, ctx_id, min_nr, nr, events, timeout);

}

#endif

/*

 * The AIO_MMAP cases force the mmapped page into memory here

 * rather than in whatever place first touches the data.  I used

 * to do this by touching the page, but that's delicate because

 * gcc is prone to optimizing that away.  So, what's done here

 * is we read from the descriptor from which the page was

 * mapped.  The caller is required to pass an offset which is

 * inside the page that was mapped.  Thus, when the read

 * returns, we know that the page is in the page cache, and

 * that it now backs the mmapped area.

 */

static int do_aio(aio_context_t ctx, enum aio_type type, int fd, char *buf,

		  int len, unsigned long long offset, struct aio_context *aio)

{

	struct iocb *iocbp = & ((struct iocb) {

				    .aio_data       = (unsigned long) aio,

				    .aio_fildes     = fd,

				    .aio_buf        = (unsigned long) buf,

				    .aio_nbytes     = len,

				    .aio_offset     = offset

			     });

	char c;

	switch (type) {

	case AIO_READ:

		iocbp->aio_lio_opcode = IOCB_CMD_PREAD;

		break;

	case AIO_WRITE:

		iocbp->aio_lio_opcode = IOCB_CMD_PWRITE;

		break;

	case AIO_MMAP:

		iocbp->aio_lio_opcode = IOCB_CMD_PREAD;

		iocbp->aio_buf = (unsigned long) &c;

		iocbp->aio_nbytes = sizeof(c);

		break;

	default:

		printk(UM_KERN_ERR "Bogus op in do_aio - %d\n", type);

		return -EINVAL;

	}

	return (io_submit(ctx, 1, &iocbp) > 0) ? 0 : -errno;

}

/* Initialized in an initcall and unchanged thereafter */

static aio_context_t ctx = 0;

static int aio_thread(void *arg)

{

	struct aio_thread_reply reply;

	struct io_event event;

	int err, n, reply_fd;

	os_fix_helper_signals();

	while (1) {

		n = io_getevents(ctx, 1, 1, &event, NULL);

		if (n < 0) {

			if (errno == EINTR)

				continue;

			printk(UM_KERN_ERR "aio_thread - io_getevents failed, "

			       "errno = %d\n", errno);

		}

		else {

			reply = ((struct aio_thread_reply)

				{ .data = (void *) (long) event.data,

						.err	= event.res });

			reply_fd = ((struct aio_context *) reply.data)->reply_fd;

			err = write(reply_fd, &reply, sizeof(reply));

			if (err != sizeof(reply))

				printk(UM_KERN_ERR "aio_thread - write failed, "

				       "fd = %d, err = %d\n", reply_fd, errno);

		}

	}

	return 0;

}

#endif

static int do_not_aio(struct aio_thread_req *req)

{

	char c;

	unsigned long long actual;

	int n;

	actual = lseek64(req->io_fd, req->offset, SEEK_SET);

	if (actual != req->offset)

		return -errno;

	switch (req->type) {

	case AIO_READ:

		n = read(req->io_fd, req->buf, req->len);

		break;

	case AIO_WRITE:

		n = write(req->io_fd, req->buf, req->len);

		break;

	case AIO_MMAP:

		n = read(req->io_fd, &c, sizeof(c));

		break;

	default:

		printk(UM_KERN_ERR "do_not_aio - bad request type : %d\n",

		       req->type);

		return -EINVAL;

	}

	if (n < 0)

		return -errno;

	return 0;

}

/* These are initialized in initcalls and not changed */

static int aio_req_fd_r = -1;

static int aio_req_fd_w = -1;

static int aio_pid = -1;

static unsigned long aio_stack;

static int not_aio_thread(void *arg)

{

	struct aio_thread_req req;

	struct aio_thread_reply reply;

	int err;

	os_fix_helper_signals();

	while (1) {

		err = read(aio_req_fd_r, &req, sizeof(req));

		if (err != sizeof(req)) {

			if (err < 0)

				printk(UM_KERN_ERR "not_aio_thread - "

				       "read failed, fd = %d, err = %d\n",

				       aio_req_fd_r,

				       errno);

			else {

				printk(UM_KERN_ERR "not_aio_thread - short "

				       "read, fd = %d, length = %d\n",

				       aio_req_fd_r, err);

			}

			continue;

		}

		err = do_not_aio(&req);

		reply = ((struct aio_thread_reply) { .data 	= req.aio,

						     .err	= err });

		err = write(req.aio->reply_fd, &reply, sizeof(reply));

		if (err != sizeof(reply))

			printk(UM_KERN_ERR "not_aio_thread - write failed, "

			       "fd = %d, err = %d\n", req.aio->reply_fd, errno);

	}

	return 0;

}

static int init_aio_24(void)

{

	int fds[2], err;

	err = os_pipe(fds, 1, 1);

	if (err)

		goto out;

	aio_req_fd_w = fds[0];

	aio_req_fd_r = fds[1];

	err = os_set_fd_block(aio_req_fd_w, 0);

	if (err)

		goto out_close_pipe;

	err = run_helper_thread(not_aio_thread, NULL,

				CLONE_FILES | CLONE_VM, &aio_stack);

	if (err < 0)

		goto out_close_pipe;

	aio_pid = err;

	goto out;

out_close_pipe:

	close(fds[0]);

	close(fds[1]);

	aio_req_fd_w = -1;

	aio_req_fd_r = -1;

out:

#ifndef HAVE_AIO_ABI

	printk(UM_KERN_INFO "/usr/include/linux/aio_abi.h not present during "

	       "build\n");

#endif

	printk(UM_KERN_INFO "2.6 host AIO support not used - falling back to "

	       "I/O thread\n");

	return 0;

}

#ifdef HAVE_AIO_ABI

#define DEFAULT_24_AIO 0

static int init_aio_26(void)

{

	int err;

	if (io_setup(256, &ctx)) {

		err = -errno;

		printk(UM_KERN_ERR "aio_thread failed to initialize context, "

		       "err = %d\n", errno);

		return err;

	}

	err = run_helper_thread(aio_thread, NULL,

				CLONE_FILES | CLONE_VM, &aio_stack);

	if (err < 0)

		return err;

	aio_pid = err;

	printk(UM_KERN_INFO "Using 2.6 host AIO\n");

	return 0;

}

static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len,

			 unsigned long long offset, struct aio_context *aio)

{

	struct aio_thread_reply reply;

	int err;

	err = do_aio(ctx, type, io_fd, buf, len, offset, aio);

	if (err) {

		reply = ((struct aio_thread_reply) { .data = aio,

					 .err  = err });

		err = write(aio->reply_fd, &reply, sizeof(reply));

		if (err != sizeof(reply)) {

			err = -errno;

			printk(UM_KERN_ERR "submit_aio_26 - write failed, "

			       "fd = %d, err = %d\n", aio->reply_fd, -err);

		}

		else err = 0;

	}

	return err;

}

#else

#define DEFAULT_24_AIO 1

static int init_aio_26(void)

{

	return -ENOSYS;

}

static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len,

			 unsigned long long offset, struct aio_context *aio)

{

	return -ENOSYS;

}

#endif

/* Initialized in an initcall and unchanged thereafter */

static int aio_24 = DEFAULT_24_AIO;

static int __init set_aio_24(char *name, int *add)

{

	aio_24 = 1;

	return 0;

}

__uml_setup("aio=2.4", set_aio_24,

"aio=2.4\n"

"    This is used to force UML to use 2.4-style AIO even when 2.6 AIO is\n"

"    available.  2.4 AIO is a single thread that handles one request at a\n"

"    time, synchronously.  2.6 AIO is a thread which uses the 2.6 AIO \n"

"    interface to handle an arbitrary number of pending requests.  2.6 AIO \n"

"    is not available in tt mode, on 2.4 hosts, or when UML is built with\n"

"    /usr/include/linux/aio_abi.h not available.  Many distributions don't\n"

"    include aio_abi.h, so you will need to copy it from a kernel tree to\n"

"    your /usr/include/linux in order to build an AIO-capable UML\n\n"

);

static int init_aio(void)

{

	int err;

	if (!aio_24) {

		err = init_aio_26();

		if (err && (errno == ENOSYS)) {

			printk(UM_KERN_INFO "2.6 AIO not supported on the "

			       "host - reverting to 2.4 AIO\n");

			aio_24 = 1;

		}

		else return err;

	}

	if (aio_24)

		return init_aio_24();

	return 0;

}

/*

 * The reason for the __initcall/__uml_exitcall asymmetry is that init_aio

 * needs to be called when the kernel is running because it calls run_helper,

 * which needs get_free_page.  exit_aio is a __uml_exitcall because the generic

 * kernel does not run __exitcalls on shutdown, and can't because many of them

 * break when called outside of module unloading.

 */

__initcall(init_aio);

static void exit_aio(void)

{

	if (aio_pid != -1) {

		os_kill_process(aio_pid, 1);

		free_stack(aio_stack, 0);

	}

}

__uml_exitcall(exit_aio);

static int submit_aio_24(enum aio_type type, int io_fd, char *buf, int len,

			 unsigned long long offset, struct aio_context *aio)

{

	struct aio_thread_req req = { .type 		= type,

				      .io_fd		= io_fd,

				      .offset		= offset,

				      .buf		= buf,

				      .len		= len,

				      .aio		= aio,

	};

	int err;

	err = write(aio_req_fd_w, &req, sizeof(req));

	if (err == sizeof(req))

		err = 0;

	else err = -errno;

	return err;

}

int submit_aio(enum aio_type type, int io_fd, char *buf, int len,

	       unsigned long long offset, int reply_fd,

	       struct aio_context *aio)

{

	aio->reply_fd = reply_fd;

	if (aio_24)

		return submit_aio_24(type, io_fd, buf, len, offset, aio);

	else

		return submit_aio_26(type, io_fd, buf, len, offset, aio);

}