#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include "liburing.h"
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static int io_uring_mmap(int fd, struct io_uring_params *p,
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struct io_uring_sq *sq, struct io_uring_cq *cq)
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{
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size_t size;
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void *ptr;
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int ret;
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sq->ring_sz = p->sq_off.array + p->sq_entries * sizeof(unsigned);
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ptr = mmap(0, sq->ring_sz, PROT_READ | PROT_WRITE,
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MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQ_RING);
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if (ptr == MAP_FAILED)
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return -errno;
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sq->khead = ptr + p->sq_off.head;
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sq->ktail = ptr + p->sq_off.tail;
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sq->kring_mask = ptr + p->sq_off.ring_mask;
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sq->kring_entries = ptr + p->sq_off.ring_entries;
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sq->kflags = ptr + p->sq_off.flags;
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sq->kdropped = ptr + p->sq_off.dropped;
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sq->array = ptr + p->sq_off.array;
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size = p->sq_entries * sizeof(struct io_uring_sqe);
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sq->sqes = mmap(0, size, PROT_READ | PROT_WRITE,
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MAP_SHARED | MAP_POPULATE, fd,
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IORING_OFF_SQES);
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if (sq->sqes == MAP_FAILED) {
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ret = -errno;
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err:
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munmap(sq->khead, sq->ring_sz);
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return ret;
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}
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cq->ring_sz = p->cq_off.cqes + p->cq_entries * sizeof(struct io_uring_cqe);
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ptr = mmap(0, cq->ring_sz, PROT_READ | PROT_WRITE,
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MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_CQ_RING);
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if (ptr == MAP_FAILED) {
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ret = -errno;
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munmap(sq->sqes, p->sq_entries * sizeof(struct io_uring_sqe));
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goto err;
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}
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cq->khead = ptr + p->cq_off.head;
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cq->ktail = ptr + p->cq_off.tail;
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cq->kring_mask = ptr + p->cq_off.ring_mask;
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cq->kring_entries = ptr + p->cq_off.ring_entries;
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cq->koverflow = ptr + p->cq_off.overflow;
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cq->cqes = ptr + p->cq_off.cqes;
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return 0;
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}
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/*
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* For users that want to specify sq_thread_cpu or sq_thread_idle, this
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* interface is a convenient helper for mmap()ing the rings.
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* Returns -1 on error, or zero on success. On success, 'ring'
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* contains the necessary information to read/write to the rings.
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*/
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int io_uring_queue_mmap(int fd, struct io_uring_params *p, struct io_uring *ring)
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{
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int ret;
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memset(ring, 0, sizeof(*ring));
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ret = io_uring_mmap(fd, p, &ring->sq, &ring->cq);
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if (!ret)
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ring->ring_fd = fd;
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return ret;
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}
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/*
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* Returns -1 on error, or zero on success. On success, 'ring'
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* contains the necessary information to read/write to the rings.
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*/
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int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
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{
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struct io_uring_params p;
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int fd, ret;
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memset(&p, 0, sizeof(p));
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p.flags = flags;
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fd = io_uring_setup(entries, &p);
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if (fd < 0)
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return fd;
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ret = io_uring_queue_mmap(fd, &p, ring);
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if (ret)
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close(fd);
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return ret;
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}
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void io_uring_queue_exit(struct io_uring *ring)
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{
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struct io_uring_sq *sq = &ring->sq;
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struct io_uring_cq *cq = &ring->cq;
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munmap(sq->sqes, *sq->kring_entries * sizeof(struct io_uring_sqe));
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munmap(sq->khead, sq->ring_sz);
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munmap(cq->khead, cq->ring_sz);
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close(ring->ring_fd);
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}
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