diff options
Diffstat (limited to 'arch/um/os-Linux/aio.c')
-rw-r--r-- | arch/um/os-Linux/aio.c | 390 |
1 files changed, 0 insertions, 390 deletions
diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c deleted file mode 100644 index 014eb35fd13b..000000000000 --- a/arch/um/os-Linux/aio.c +++ /dev/null @@ -1,390 +0,0 @@ -/* - * 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); -} |