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