forked from mirrors/linux
5fb94e9ca3
As we move stuff around, some doc references are broken. Fix some of them via this script: ./scripts/documentation-file-ref-check --fix Manually checked if the produced result is valid, removing a few false-positives. Acked-by: Takashi Iwai <tiwai@suse.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Stephen Boyd <sboyd@kernel.org> Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> Reviewed-by: Coly Li <colyli@suse.de> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Jonathan Corbet <corbet@lwn.net>
37 lines
1.1 KiB
C
37 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* See Documentation/core-api/circular-buffers.rst for more information.
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*/
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#ifndef _LINUX_CIRC_BUF_H
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#define _LINUX_CIRC_BUF_H 1
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struct circ_buf {
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char *buf;
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int head;
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int tail;
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};
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/* Return count in buffer. */
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#define CIRC_CNT(head,tail,size) (((head) - (tail)) & ((size)-1))
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/* Return space available, 0..size-1. We always leave one free char
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as a completely full buffer has head == tail, which is the same as
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empty. */
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#define CIRC_SPACE(head,tail,size) CIRC_CNT((tail),((head)+1),(size))
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/* Return count up to the end of the buffer. Carefully avoid
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accessing head and tail more than once, so they can change
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underneath us without returning inconsistent results. */
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#define CIRC_CNT_TO_END(head,tail,size) \
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({int end = (size) - (tail); \
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int n = ((head) + end) & ((size)-1); \
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n < end ? n : end;})
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/* Return space available up to the end of the buffer. */
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#define CIRC_SPACE_TO_END(head,tail,size) \
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({int end = (size) - 1 - (head); \
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int n = (end + (tail)) & ((size)-1); \
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n <= end ? n : end+1;})
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#endif /* _LINUX_CIRC_BUF_H */
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