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, 81 insertions, 0 deletions

diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
new file mode 100644
index 000000000..9a0bb623e
--- /dev/null
+++ b/drivers/md/dm-zero.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2003 Jana Saout <jana@saout.de>
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/device-mapper.h>
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+
+#define DM_MSG_PREFIX "zero"
+
+/*
+ * Construct a dummy mapping that only returns zeros
+ */
+static int zero_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	if (argc != 0) {
+		ti->error = "No arguments required";
+		return -EINVAL;
+	}
+
+	/*
+	 * Silently drop discards, avoiding -EOPNOTSUPP.
+	 */
+	ti->num_discard_bios = 1;
+	ti->discards_supported = true;
+
+	return 0;
+}
+
+/*
+ * Return zeros only on reads
+ */
+static int zero_map(struct dm_target *ti, struct bio *bio)
+{
+	switch (bio_op(bio)) {
+	case REQ_OP_READ:
+		if (bio->bi_opf & REQ_RAHEAD) {
+			/* readahead of null bytes only wastes buffer cache */
+			return DM_MAPIO_KILL;
+		}
+		zero_fill_bio(bio);
+		break;
+	case REQ_OP_WRITE:
+	case REQ_OP_DISCARD:
+		/* writes get silently dropped */
+		break;
+	default:
+		return DM_MAPIO_KILL;
+	}
+
+	bio_endio(bio);
+
+	/* accepted bio, don't make new request */
+	return DM_MAPIO_SUBMITTED;
+}
+
+static void zero_io_hints(struct dm_target *ti, struct queue_limits *limits)
+{
+	limits->max_hw_discard_sectors = UINT_MAX;
+	limits->discard_granularity = 512;
+}
+
+static struct target_type zero_target = {
+	.name   = "zero",
+	.version = {1, 2, 0},
+	.features = DM_TARGET_NOWAIT,
+	.module = THIS_MODULE,
+	.ctr    = zero_ctr,
+	.map    = zero_map,
+	.io_hints = zero_io_hints,
+};
+module_dm(zero);
+
+MODULE_AUTHOR("Jana Saout <jana@saout.de>");
+MODULE_DESCRIPTION(DM_NAME " dummy target returning zeros");
+MODULE_LICENSE("GPL");