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