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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);
- }
- /*
- * 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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