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// SPDX-License-Identifier: GPL-2.0
#include <unistd.h>
#include <stdbool.h>
#include <errno.h>
#include <linux/kernel.h>
#include <internal/lib.h>
unsigned int page_size;
static ssize_t ion(bool is_read, int fd, void *buf, size_t n)
{
void *buf_start = buf;
size_t left = n;
while (left) {
/* buf must be treated as const if !is_read. */
ssize_t ret = is_read ? read(fd, buf, left) :
write(fd, buf, left);
if (ret < 0 && errno == EINTR)
continue;
if (ret <= 0)
return ret;
left -= ret;
buf += ret;
}
BUG_ON((size_t)(buf - buf_start) != n);
return n;
}
/*
* Read exactly 'n' bytes or return an error.
*/
ssize_t readn(int fd, void *buf, size_t n)
{
return ion(true, fd, buf, n);
}
ssize_t preadn(int fd, void *buf, size_t n, off_t offs)
{
size_t left = n;
while (left) {
ssize_t ret = pread(fd, buf, left, offs);
if (ret < 0 && errno == EINTR)
continue;
if (ret <= 0)
return ret;
left -= ret;
buf += ret;
offs += ret;
}
return n;
}
/*
* Write exactly 'n' bytes or return an error.
*/
ssize_t writen(int fd, const void *buf, size_t n)
{
/* ion does not modify buf. */
return ion(false, fd, (void *)buf, n);
}
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