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From:   Guanghui Feng <guanghuifeng@linux.alibaba.com>
To:     lpieralisi@kernel.org, guohanjun@huawei.com, sudeep.holla@arm.com,
        rafael@kernel.org
Cc:     linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, baolin.wang@linux.alibaba.com,
        alikernel-developer@linux.alibaba.com
Subject: [PATCH v3] ACPI/IORT: Remove erroneous id_count check in iort_node_get_rmr_info()
Date:   Mon, 17 Jul 2023 19:33:45 +0800
Message-Id: <1689593625-45213-1-git-send-email-guanghuifeng@linux.alibaba.com>
Precedence: bulk

According to the ARM IORT specifications DEN 0049 issue E,
the "Number of IDs" field in the ID mapping format reports
the number of IDs in the mapping range minus one.

In iort_node_get_rmr_info(), we erroneously skip ID mappings
whose "Number of IDs" equal to 0, resulting in valid mapping
nodes with a single ID to map being skipped, which is wrong.

Fix iort_node_get_rmr_info() by removing the bogus id_count
check.

Fixes: 491cf4a6735a ("ACPI/IORT: Add support to retrieve IORT RMR reserved regions")
Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com>
---
 drivers/acpi/arm64/iort.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 3631230..56d8873 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1007,9 +1007,6 @@ static void iort_node_get_rmr_info(struct acpi_iort_node *node,
 	for (i = 0; i < node->mapping_count; i++, map++) {
 		struct acpi_iort_node *parent;
 
-		if (!map->id_count)
-			continue;
-
 		parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
 				      map->output_reference);
 		if (parent != iommu)
-- 
1.8.3.1