ata: libata-scsi: fix ata_dsm_trim_pages() kernel-docgrafted

make htmldocs fails with:

  Documentation/driver-api/libata:604: ./drivers/ata/libata-scsi.c:2301:
  ERROR: Unexpected indentation. [docutils]

The Return: section of ata_dsm_trim_pages() ends its first sentence with
a colon and continues with an indented bullet list. reStructuredText
requires a blank line before an indented block, so docutils chokes on
the list.

Simply adding the missing blank line does not work either: Return: is a
kernel-doc "special section", which is terminated by the first blank
line, so the bullet list would end up in the Description section,
detached from the sentence introducing it.

Spell the two bounds out as prose instead, so that the Return: section
stays self-contained. Documentation-only change.

Fixes: e64e6b5dc867 ("ata: libata-scsi: scale DSM TRIM payload by MAX PAGES PER DSM COMMAND")
Reported-by: Thomas Huth <thuth@redhat.com>
Closes: https://lore.kernel.org/linux-ide/b0a0b8e8-cc4f-4c7b-8bc5-fee0712d405a@redhat.com/
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20260916130031.29990-2-cassel@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>

1 files changed, 201 insertions, 0 deletions

diff --git a/tools/lib/api/io.h b/tools/lib/api/io.h
new file mode 100644
index 000000000..1731996b2
--- /dev/null
+++ b/tools/lib/api/io.h
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Lightweight buffered reading library.
+ *
+ * Copyright 2019 Google LLC.
+ */
+#ifndef __API_IO__
+#define __API_IO__
+
+#include <errno.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/types.h>
+
+struct io {
+	/* File descriptor being read/ */
+	int fd;
+	/* Size of the read buffer. */
+	unsigned int buf_len;
+	/* Pointer to storage for buffering read. */
+	char *buf;
+	/* End of the storage. */
+	char *end;
+	/* Currently accessed data pointer. */
+	char *data;
+	/* Read timeout, 0 implies no timeout. */
+	int timeout_ms;
+	/* Set true on when the end of file on read error. */
+	bool eof;
+};
+
+static inline void io__init(struct io *io, int fd,
+			    char *buf, unsigned int buf_len)
+{
+	io->fd = fd;
+	io->buf_len = buf_len;
+	io->buf = buf;
+	io->end = buf;
+	io->data = buf;
+	io->timeout_ms = 0;
+	io->eof = false;
+}
+
+/* Read from fd filling the buffer. Called when io->data == io->end. */
+static inline int io__fill_buffer(struct io *io)
+{
+	ssize_t n;
+
+	if (io->eof)
+		return -1;
+
+	if (io->timeout_ms != 0) {
+		struct pollfd pfds[] = {
+			{
+				.fd = io->fd,
+				.events = POLLIN,
+			},
+		};
+
+		n = poll(pfds, 1, io->timeout_ms);
+		if (n == 0)
+			errno = ETIMEDOUT;
+		if (n > 0 && !(pfds[0].revents & POLLIN)) {
+			errno = EIO;
+			n = -1;
+		}
+		if (n <= 0) {
+			io->eof = true;
+			return -1;
+		}
+	}
+	n = read(io->fd, io->buf, io->buf_len);
+
+	if (n <= 0) {
+		io->eof = true;
+		return -1;
+	}
+	io->data = &io->buf[0];
+	io->end = &io->buf[n];
+	return 0;
+}
+
+/* Reads one character from the "io" file with similar semantics to fgetc. */
+static inline int io__get_char(struct io *io)
+{
+	if (io->data == io->end) {
+		int ret = io__fill_buffer(io);
+
+		if (ret)
+			return ret;
+	}
+	return *io->data++;
+}
+
+/* Read a hexadecimal value with no 0x prefix into the out argument hex. If the
+ * first character isn't hexadecimal returns -2, io->eof returns -1, otherwise
+ * returns the character after the hexadecimal value which may be -1 for eof.
+ * If the read value is larger than a u64 the high-order bits will be dropped.
+ */
+static inline int io__get_hex(struct io *io, __u64 *hex)
+{
+	bool first_read = true;
+
+	*hex = 0;
+	while (true) {
+		int ch = io__get_char(io);
+
+		if (ch < 0)
+			return ch;
+		if (ch >= '0' && ch <= '9')
+			*hex = (*hex << 4) | (ch - '0');
+		else if (ch >= 'a' && ch <= 'f')
+			*hex = (*hex << 4) | (ch - 'a' + 10);
+		else if (ch >= 'A' && ch <= 'F')
+			*hex = (*hex << 4) | (ch - 'A' + 10);
+		else if (first_read)
+			return -2;
+		else
+			return ch;
+		first_read = false;
+	}
+}
+
+/* Read a positive decimal value with out argument dec. If the first character
+ * isn't a decimal returns -2, io->eof returns -1, otherwise returns the
+ * character after the decimal value which may be -1 for eof. If the read value
+ * is larger than a u64 the high-order bits will be dropped.
+ */
+static inline int io__get_dec(struct io *io, __u64 *dec)
+{
+	bool first_read = true;
+
+	*dec = 0;
+	while (true) {
+		int ch = io__get_char(io);
+
+		if (ch < 0)
+			return ch;
+		if (ch >= '0' && ch <= '9')
+			*dec = (*dec * 10) + ch - '0';
+		else if (first_read)
+			return -2;
+		else
+			return ch;
+		first_read = false;
+	}
+}
+
+/* Read up to and including the first delim. */
+static inline ssize_t io__getdelim(struct io *io, char **line_out, size_t *line_len_out, int delim)
+{
+	char buf[128];
+	int buf_pos = 0;
+	char *line = NULL, *temp;
+	size_t line_len = 0;
+	int ch = 0;
+
+	/* TODO: reuse previously allocated memory. */
+	free(*line_out);
+	while (ch != delim) {
+		ch = io__get_char(io);
+
+		if (ch < 0)
+			break;
+
+		if (buf_pos == sizeof(buf)) {
+			temp = realloc(line, line_len + sizeof(buf));
+			if (!temp)
+				goto err_out;
+			line = temp;
+			memcpy(&line[line_len], buf, sizeof(buf));
+			line_len += sizeof(buf);
+			buf_pos = 0;
+		}
+		buf[buf_pos++] = (char)ch;
+	}
+	temp = realloc(line, line_len + buf_pos + 1);
+	if (!temp)
+		goto err_out;
+	line = temp;
+	memcpy(&line[line_len], buf, buf_pos);
+	line[line_len + buf_pos] = '\0';
+	line_len += buf_pos;
+	*line_out = line;
+	*line_len_out = line_len;
+	return line_len;
+err_out:
+	free(line);
+	*line_out = NULL;
+	*line_len_out = 0;
+	return -ENOMEM;
+}
+
+static inline ssize_t io__getline(struct io *io, char **line_out, size_t *line_len_out)
+{
+	return io__getdelim(io, line_out, line_len_out, /*delim=*/'\n');
+}
+
+#endif /* __API_IO__ */