+++ /dev/null
-/*
- * 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);
-}
projects / kernel.git / commitdiff