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, 393 insertions, 0 deletions

diff --git a/include/net/fq_impl.h b/include/net/fq_impl.h
new file mode 100644
index 000000000..8aca88193
--- /dev/null
+++ b/include/net/fq_impl.h
@@ -0,0 +1,393 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2016 Qualcomm Atheros, Inc
+ *
+ * Based on net/sched/sch_fq_codel.c
+ */
+#ifndef __NET_SCHED_FQ_IMPL_H
+#define __NET_SCHED_FQ_IMPL_H
+
+#include <net/fq.h>
+
+/* functions that are embedded into includer */
+
+
+static void
+__fq_adjust_removal(struct fq *fq, struct fq_flow *flow, unsigned int packets,
+		    unsigned int bytes, unsigned int truesize)
+{
+	struct fq_tin *tin = flow->tin;
+	int idx;
+
+	tin->backlog_bytes -= bytes;
+	tin->backlog_packets -= packets;
+	flow->backlog -= bytes;
+	fq->backlog -= packets;
+	fq->memory_usage -= truesize;
+
+	if (flow->backlog)
+		return;
+
+	if (flow == &tin->default_flow) {
+		list_del_init(&tin->tin_list);
+		return;
+	}
+
+	idx = flow - fq->flows;
+	__clear_bit(idx, fq->flows_bitmap);
+}
+
+static void fq_adjust_removal(struct fq *fq,
+			      struct fq_flow *flow,
+			      struct sk_buff *skb)
+{
+	__fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
+}
+
+static struct sk_buff *fq_flow_dequeue(struct fq *fq,
+				       struct fq_flow *flow)
+{
+	struct sk_buff *skb;
+
+	lockdep_assert_held(&fq->lock);
+
+	skb = __skb_dequeue(&flow->queue);
+	if (!skb)
+		return NULL;
+
+	fq_adjust_removal(fq, flow, skb);
+
+	return skb;
+}
+
+static int fq_flow_drop(struct fq *fq, struct fq_flow *flow,
+			fq_skb_free_t free_func)
+{
+	unsigned int packets = 0, bytes = 0, truesize = 0;
+	struct fq_tin *tin = flow->tin;
+	struct sk_buff *skb;
+	int pending;
+
+	lockdep_assert_held(&fq->lock);
+
+	pending = min_t(int, 32, skb_queue_len(&flow->queue) / 2);
+	do {
+		skb = __skb_dequeue(&flow->queue);
+		if (!skb)
+			break;
+
+		packets++;
+		bytes += skb->len;
+		truesize += skb->truesize;
+		free_func(fq, tin, flow, skb);
+	} while (packets < pending);
+
+	__fq_adjust_removal(fq, flow, packets, bytes, truesize);
+
+	return packets;
+}
+
+static struct sk_buff *fq_tin_dequeue(struct fq *fq,
+				      struct fq_tin *tin,
+				      fq_tin_dequeue_t dequeue_func)
+{
+	struct fq_flow *flow;
+	struct list_head *head;
+	struct sk_buff *skb;
+
+	lockdep_assert_held(&fq->lock);
+
+begin:
+	head = &tin->new_flows;
+	if (list_empty(head)) {
+		head = &tin->old_flows;
+		if (list_empty(head))
+			return NULL;
+	}
+
+	flow = list_first_entry(head, struct fq_flow, flowchain);
+
+	if (flow->deficit <= 0) {
+		flow->deficit += fq->quantum;
+		list_move_tail(&flow->flowchain,
+			       &tin->old_flows);
+		goto begin;
+	}
+
+	skb = dequeue_func(fq, tin, flow);
+	if (!skb) {
+		/* force a pass through old_flows to prevent starvation */
+		if ((head == &tin->new_flows) &&
+		    !list_empty(&tin->old_flows)) {
+			list_move_tail(&flow->flowchain, &tin->old_flows);
+		} else {
+			list_del_init(&flow->flowchain);
+			flow->tin = NULL;
+		}
+		goto begin;
+	}
+
+	flow->deficit -= skb->len;
+	tin->tx_bytes += skb->len;
+	tin->tx_packets++;
+
+	return skb;
+}
+
+static u32 fq_flow_idx(struct fq *fq, struct sk_buff *skb)
+{
+	u32 hash = skb_get_hash(skb);
+
+	return reciprocal_scale(hash, fq->flows_cnt);
+}
+
+static struct fq_flow *fq_flow_classify(struct fq *fq,
+					struct fq_tin *tin, u32 idx,
+					struct sk_buff *skb)
+{
+	struct fq_flow *flow;
+
+	lockdep_assert_held(&fq->lock);
+
+	flow = &fq->flows[idx];
+	if (flow->tin && flow->tin != tin) {
+		flow = &tin->default_flow;
+		tin->collisions++;
+		fq->collisions++;
+	}
+
+	if (!flow->tin)
+		tin->flows++;
+
+	return flow;
+}
+
+static struct fq_flow *fq_find_fattest_flow(struct fq *fq)
+{
+	struct fq_tin *tin;
+	struct fq_flow *flow = NULL;
+	u32 len = 0;
+	int i;
+
+	for_each_set_bit(i, fq->flows_bitmap, fq->flows_cnt) {
+		struct fq_flow *cur = &fq->flows[i];
+		unsigned int cur_len;
+
+		cur_len = cur->backlog;
+		if (cur_len <= len)
+			continue;
+
+		flow = cur;
+		len = cur_len;
+	}
+
+	list_for_each_entry(tin, &fq->tin_backlog, tin_list) {
+		unsigned int cur_len = tin->default_flow.backlog;
+
+		if (cur_len <= len)
+			continue;
+
+		flow = &tin->default_flow;
+		len = cur_len;
+	}
+
+	return flow;
+}
+
+static void fq_tin_enqueue(struct fq *fq,
+			   struct fq_tin *tin, u32 idx,
+			   struct sk_buff *skb,
+			   fq_skb_free_t free_func)
+{
+	struct fq_flow *flow;
+	struct sk_buff *next;
+	bool oom;
+
+	lockdep_assert_held(&fq->lock);
+
+	flow = fq_flow_classify(fq, tin, idx, skb);
+
+	if (!flow->backlog) {
+		if (flow != &tin->default_flow)
+			__set_bit(idx, fq->flows_bitmap);
+		else if (list_empty(&tin->tin_list))
+			list_add(&tin->tin_list, &fq->tin_backlog);
+	}
+
+	flow->tin = tin;
+	skb_list_walk_safe(skb, skb, next) {
+		skb_mark_not_on_list(skb);
+		flow->backlog += skb->len;
+		tin->backlog_bytes += skb->len;
+		tin->backlog_packets++;
+		fq->memory_usage += skb->truesize;
+		fq->backlog++;
+		__skb_queue_tail(&flow->queue, skb);
+	}
+
+	if (list_empty(&flow->flowchain)) {
+		flow->deficit = fq->quantum;
+		list_add_tail(&flow->flowchain,
+			      &tin->new_flows);
+	}
+
+	oom = (fq->memory_usage > fq->memory_limit);
+	while (fq->backlog > fq->limit || oom) {
+		flow = fq_find_fattest_flow(fq);
+		if (!flow)
+			return;
+
+		if (!fq_flow_drop(fq, flow, free_func))
+			return;
+
+		flow->tin->overlimit++;
+		fq->overlimit++;
+		if (oom) {
+			fq->overmemory++;
+			oom = (fq->memory_usage > fq->memory_limit);
+		}
+	}
+}
+
+static void fq_flow_filter(struct fq *fq,
+			   struct fq_flow *flow,
+			   fq_skb_filter_t filter_func,
+			   void *filter_data,
+			   fq_skb_free_t free_func)
+{
+	struct fq_tin *tin = flow->tin;
+	struct sk_buff *skb, *tmp;
+
+	lockdep_assert_held(&fq->lock);
+
+	skb_queue_walk_safe(&flow->queue, skb, tmp) {
+		if (!filter_func(fq, tin, flow, skb, filter_data))
+			continue;
+
+		__skb_unlink(skb, &flow->queue);
+		fq_adjust_removal(fq, flow, skb);
+		free_func(fq, tin, flow, skb);
+	}
+}
+
+static void fq_tin_filter(struct fq *fq,
+			  struct fq_tin *tin,
+			  fq_skb_filter_t filter_func,
+			  void *filter_data,
+			  fq_skb_free_t free_func)
+{
+	struct fq_flow *flow;
+
+	lockdep_assert_held(&fq->lock);
+
+	list_for_each_entry(flow, &tin->new_flows, flowchain)
+		fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
+	list_for_each_entry(flow, &tin->old_flows, flowchain)
+		fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
+}
+
+static void fq_flow_reset(struct fq *fq,
+			  struct fq_flow *flow,
+			  fq_skb_free_t free_func)
+{
+	struct fq_tin *tin = flow->tin;
+	struct sk_buff *skb;
+
+	while ((skb = fq_flow_dequeue(fq, flow)))
+		free_func(fq, tin, flow, skb);
+
+	if (!list_empty(&flow->flowchain)) {
+		list_del_init(&flow->flowchain);
+		if (list_empty(&tin->new_flows) &&
+		    list_empty(&tin->old_flows))
+			list_del_init(&tin->tin_list);
+	}
+
+	flow->tin = NULL;
+
+	WARN_ON_ONCE(flow->backlog);
+}
+
+static void fq_tin_reset(struct fq *fq,
+			 struct fq_tin *tin,
+			 fq_skb_free_t free_func)
+{
+	struct list_head *head;
+	struct fq_flow *flow;
+
+	for (;;) {
+		head = &tin->new_flows;
+		if (list_empty(head)) {
+			head = &tin->old_flows;
+			if (list_empty(head))
+				break;
+		}
+
+		flow = list_first_entry(head, struct fq_flow, flowchain);
+		fq_flow_reset(fq, flow, free_func);
+	}
+
+	WARN_ON_ONCE(!list_empty(&tin->tin_list));
+	WARN_ON_ONCE(tin->backlog_bytes);
+	WARN_ON_ONCE(tin->backlog_packets);
+}
+
+static void fq_flow_init(struct fq_flow *flow)
+{
+	INIT_LIST_HEAD(&flow->flowchain);
+	__skb_queue_head_init(&flow->queue);
+}
+
+static void fq_tin_init(struct fq_tin *tin)
+{
+	INIT_LIST_HEAD(&tin->new_flows);
+	INIT_LIST_HEAD(&tin->old_flows);
+	INIT_LIST_HEAD(&tin->tin_list);
+	fq_flow_init(&tin->default_flow);
+}
+
+static int fq_init(struct fq *fq, int flows_cnt)
+{
+	int i;
+
+	memset(fq, 0, sizeof(fq[0]));
+	spin_lock_init(&fq->lock);
+	INIT_LIST_HEAD(&fq->tin_backlog);
+	fq->flows_cnt = max_t(u32, flows_cnt, 1);
+	fq->quantum = 300;
+	fq->limit = 8192;
+	fq->memory_limit = 16 << 20; /* 16 MBytes */
+
+	fq->flows = kvzalloc_objs(fq->flows[0], fq->flows_cnt);
+	if (!fq->flows)
+		return -ENOMEM;
+
+	fq->flows_bitmap = bitmap_zalloc(fq->flows_cnt, GFP_KERNEL);
+	if (!fq->flows_bitmap) {
+		kvfree(fq->flows);
+		fq->flows = NULL;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < fq->flows_cnt; i++)
+		fq_flow_init(&fq->flows[i]);
+
+	return 0;
+}
+
+static void fq_reset(struct fq *fq,
+		     fq_skb_free_t free_func)
+{
+	int i;
+
+	for (i = 0; i < fq->flows_cnt; i++)
+		fq_flow_reset(fq, &fq->flows[i], free_func);
+
+	kvfree(fq->flows);
+	fq->flows = NULL;
+
+	bitmap_free(fq->flows_bitmap);
+	fq->flows_bitmap = NULL;
+}
+
+#endif