From 06ae7118aaa74aa2139004fa12b4910bc15236de Mon Sep 17 00:00:00 2001

From: Dan Williams <dan.j.williams@intel.com>

Date: Thu, 14 Jul 2022 10:02:21 -0700

Subject: [PATCH 180/217] cxl/lib: Maintain decoders in id order

Given that decoder instance order is fundamental to the DPA translation

sequence for endpoint decoders, enforce that cxl_decoder_for_each() returns

decoders in instance order. Otherwise, they show up in readddir() order

which is not predictable.

Add a list_add_sorted() to generically handle inserting into a sorted list.

Link: https://lore.kernel.org/r/165781814167.1555691.14895625637451030942.stgit@dwillia2-xfh.jf.intel.com

Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

---

 cxl/lib/libcxl.c |  8 +++++++-

 util/list.h      | 39 +++++++++++++++++++++++++++++++++++++++

 2 files changed, 46 insertions(+), 1 deletion(-)

 create mode 100644 util/list.h

diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c

index 6f4d64d..ea597f6 100644

--- a/cxl/lib/libcxl.c

+++ b/cxl/lib/libcxl.c

@@ -19,6 +19,7 @@

 #include <ccan/short_types/short_types.h>

 #include <util/log.h>

+#include <util/list.h>

 #include <util/size.h>

 #include <util/sysfs.h>

 #include <util/bitmap.h>

@@ -909,6 +910,11 @@ cxl_endpoint_get_memdev(struct cxl_endpoint *endpoint)

 	return NULL;

 }

+static int decoder_id_cmp(struct cxl_decoder *d1, struct cxl_decoder *d2)

+{

+	return d1->id - d2->id;

+}

+

 static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)

 {

 	const char *devname = devpath_to_devname(cxldecoder_base);

@@ -1050,7 +1056,7 @@ static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)

 			return decoder_dup;

 		}

-	list_add(&port->decoders, &decoder->list);

+	list_add_sorted(&port->decoders, decoder, list, decoder_id_cmp);

 	free(path);

 	return decoder;

diff --git a/util/list.h b/util/list.h

new file mode 100644

index 0000000..cb77271

--- /dev/null

+++ b/util/list.h

@@ -0,0 +1,39 @@

+/* SPDX-License-Identifier: GPL-2.0 */

+/* Copyright (C) 2022 Intel Corporation. All rights reserved. */

+#ifndef _NDCTL_LIST_H_

+#define _NDCTL_LIST_H_

+

+#include <ccan/list/list.h>

+

+#define list_add_sorted(head, n, node, cmp)                                    \

+	do {                                                                   \

+		struct list_head *__head = (head);                             \

+		typeof(n) __iter, __next;                                      \

+		typeof(n) __new = (n);                                         \

+                                                                               \

+		if (list_empty(__head)) {                                      \

+			list_add(__head, &__new->node);                        \

+			break;                                                 \

+		}                                                              \

+                                                                               \

+		list_for_each (__head, __iter, node) {                         \

+			if (cmp(__new, __iter) < 0) {                          \

+				list_add_before(__head, &__iter->node,         \

+						&__new->node);                 \

+				break;                                         \

+			}                                                      \

+			__next = list_next(__head, __iter, node);              \

+			if (!__next) {                                         \

+				list_add_after(__head, &__iter->node,          \

+					       &__new->node);                  \

+				break;                                         \

+			}                                                      \

+			if (cmp(__new, __next) < 0) {                          \

+				list_add_before(__head, &__next->node,         \

+						&__new->node);                 \

+				break;                                         \

+			}                                                      \

+		}                                                              \

+	} while (0)

+

+#endif /* _NDCTL_LIST_H_ */

-- 

2.27.0