286 lines
6.6 KiB
C
286 lines
6.6 KiB
C
/*
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* Copyright (c) 2006-2023, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2023-07-20 zmq810150896 first version
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*/
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#include <rtthread.h>
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#include <fcntl.h>
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#include <rtdevice.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <dfs_file.h>
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#include <dfs.h>
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#include "poll.h"
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#include "eventfd.h"
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#define EFD_SEMAPHORE (1 << 0)
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#define EFD_CLOEXEC O_CLOEXEC
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#define EFD_NONBLOCK O_NONBLOCK
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#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
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#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
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#define ULLONG_MAX (~0ULL)
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#define EVENTFD_MUTEX_NAME "eventfd"
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struct eventfd_ctx
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{
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rt_wqueue_t reader_queue;
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rt_wqueue_t writer_queue;
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rt_uint64_t count;
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unsigned int flags;
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struct rt_mutex lock;
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};
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#ifndef RT_USING_DFS_V2
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static int eventfd_close(struct dfs_file *file);
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static int eventfd_poll(struct dfs_file *file, struct rt_pollreq *req);
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static ssize_t eventfd_read(struct dfs_file *file, void *buf, size_t count);
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static ssize_t eventfd_write(struct dfs_file *file, const void *buf, size_t count);
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#else
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static int eventfd_close(struct dfs_file *file);
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static int eventfd_poll(struct dfs_file *file, struct rt_pollreq *req);
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static ssize_t eventfd_read(struct dfs_file *file, void *buf, size_t count, off_t *pos);
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static ssize_t eventfd_write(struct dfs_file *file, const void *buf, size_t count, off_t *pos);
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#endif
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static const struct dfs_file_ops eventfd_fops =
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{
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.close = eventfd_close,
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.poll = eventfd_poll,
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.read = eventfd_read,
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.write = eventfd_write,
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};
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static int eventfd_close(struct dfs_file *file)
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{
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struct eventfd_ctx *ctx = file->vnode->data;
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if (file->vnode->ref_count == 1)
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{
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rt_mutex_detach(&ctx->lock);
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rt_free(ctx);
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}
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return 0;
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}
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static int eventfd_poll(struct dfs_file *file, struct rt_pollreq *req)
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{
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struct eventfd_ctx *ctx = (struct eventfd_ctx *)file->vnode->data;
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int events = 0;
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rt_uint64_t count;
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count = ctx->count;
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rt_poll_add(&ctx->reader_queue, req);
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if (count > 0)
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events |= POLLIN;
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if (count == ULLONG_MAX)
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events |= POLLERR;
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if ((ULLONG_MAX - 1) > count)
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events |= POLLOUT;
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return events;
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}
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#ifndef RT_USING_DFS_V2
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static ssize_t eventfd_read(struct dfs_file *file, void *buf, size_t count)
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#else
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static ssize_t eventfd_read(struct dfs_file *file, void *buf, size_t count, off_t *pos)
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#endif
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{
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struct eventfd_ctx *ctx = (struct eventfd_ctx *)file->vnode->data;
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rt_uint64_t counter_num = 0;
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rt_uint64_t *buffer;
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if (count < sizeof(counter_num))
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return -EINVAL;
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buffer = (rt_uint64_t *)buf;
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rt_mutex_take(&ctx->lock, RT_WAITING_FOREVER);
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if (ctx->count <= 0)
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{
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if (file->flags & O_NONBLOCK)
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{
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rt_wqueue_wakeup(&ctx->writer_queue, (void*)POLLOUT);
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rt_mutex_release(&ctx->lock);
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return -EAGAIN;
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}
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else
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{
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/* In this case, when the data is read in blocked mode, when ctx->count is 0, the mutex needs to be released and wait for writing */
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rt_mutex_release(&ctx->lock);
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rt_wqueue_wakeup(&ctx->writer_queue, (void*)POLLOUT);
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rt_wqueue_wait(&ctx->reader_queue, 0, RT_WAITING_FOREVER);
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rt_mutex_take(&ctx->lock, RT_WAITING_FOREVER);
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}
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}
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if (ctx->flags & EFD_SEMAPHORE)
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{
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counter_num = 1;
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}
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else
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{
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counter_num = ctx->count;
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}
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ctx->count -= counter_num;
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(*buffer) = counter_num;
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rt_mutex_release(&ctx->lock);
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return sizeof(counter_num);
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}
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#ifndef RT_USING_DFS_V2
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static ssize_t eventfd_write(struct dfs_file *file, const void *buf, size_t count)
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#else
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static ssize_t eventfd_write(struct dfs_file *file, const void *buf, size_t count, off_t *pos)
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#endif
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{
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struct eventfd_ctx *ctx = (struct eventfd_ctx *)file->vnode->data;
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rt_ssize_t ret = 0;
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rt_uint64_t counter_num;
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if (count < sizeof(counter_num))
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return -EINVAL;
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counter_num = *(rt_uint64_t *)buf;
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if (counter_num == ULLONG_MAX)
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return -EINVAL;
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ret = -EAGAIN;
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rt_mutex_take(&ctx->lock, RT_WAITING_FOREVER);
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if ((ULLONG_MAX - ctx->count) > counter_num)
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{
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ret = sizeof(counter_num);
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}
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else if (!(file->flags & O_NONBLOCK))
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{
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for (;;)
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{
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if ((ULLONG_MAX - ctx->count) >= counter_num)
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{
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ret = sizeof(counter_num);
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break;
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}
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/* Release the mutex to avoid a deadlock */
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rt_mutex_release(&ctx->lock);
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rt_wqueue_wait(&ctx->writer_queue, 0, RT_WAITING_FOREVER);
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rt_mutex_take(&ctx->lock, RT_WAITING_FOREVER);
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}
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}
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if (ret > 0)
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{
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ctx->count += counter_num;
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rt_wqueue_wakeup(&ctx->reader_queue, (void *)POLLIN);
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}
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rt_mutex_release(&ctx->lock);
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return ret;
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}
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static int rt_eventfd_create(struct dfs_file *df, unsigned int count, int flags)
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{
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struct eventfd_ctx *ctx = RT_NULL;
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rt_err_t ret = 0;
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ctx = (struct eventfd_ctx *)rt_malloc(sizeof(struct eventfd_ctx));
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if (ctx == RT_NULL)
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{
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ret = -ENOMEM;
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}
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else
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{
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ctx->count = count;
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ctx->flags = flags;
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flags &= EFD_SHARED_FCNTL_FLAGS;
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flags |= O_RDWR;
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rt_mutex_init(&ctx->lock, EVENTFD_MUTEX_NAME, RT_IPC_FLAG_FIFO);
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rt_wqueue_init(&ctx->reader_queue);
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rt_wqueue_init(&ctx->writer_queue);
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df->vnode = (struct dfs_vnode *)rt_malloc(sizeof(struct dfs_vnode));
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if (df->vnode)
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{
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dfs_vnode_init(df->vnode, FT_NONLOCK, &eventfd_fops);
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df->vnode->data = ctx;
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df->flags = flags;
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}
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else
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{
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rt_mutex_detach(&ctx->lock);
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rt_free(ctx);
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ret = -ENOMEM;
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}
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#ifdef RT_USING_DFS_V2
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df->fops = &eventfd_fops;
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#endif
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}
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return ret;
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}
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static int do_eventfd(unsigned int count, int flags)
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{
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struct dfs_file *file;
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int fd;
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int status;
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rt_ssize_t ret = 0;
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if (flags & ~EFD_FLAGS_SET)
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{
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rt_set_errno(EINVAL);
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return -1;
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}
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fd = fd_new();
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if (fd >= 0)
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{
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ret = fd;
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file = fd_get(fd);
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status = rt_eventfd_create(file, count, flags);
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if (status < 0)
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{
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fd_release(fd);
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rt_set_errno(-status);
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ret = -1;
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}
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}
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else
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{
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rt_set_errno(-fd);
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ret = -1;
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}
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return ret;
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}
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int eventfd(unsigned int count, int flags)
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{
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return do_eventfd(count, flags);
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}
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