netdev - [PATCH v4 10/26] cxl: harden resource_contains checks to handle zero size resources

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Message-ID: <20241017165225.21206-11-alejandro.lucero-palau@amd.com>
Date: Thu, 17 Oct 2024 17:52:09 +0100
From: <alejandro.lucero-palau@....com>
To: <linux-cxl@...r.kernel.org>, <netdev@...r.kernel.org>,
	<dan.j.williams@...el.com>, <martin.habets@...inx.com>,
	<edward.cree@....com>, <davem@...emloft.net>, <kuba@...nel.org>,
	<pabeni@...hat.com>, <edumazet@...gle.com>
CC: Alejandro Lucero <alucerop@....com>
Subject: [PATCH v4 10/26] cxl: harden resource_contains checks to handle zero size resources

From: Alejandro Lucero <alucerop@....com>

For a resource defined with size zero, resource_contains returns
always true.

Add resource size check before using it.

Signed-off-by: Alejandro Lucero <alucerop@....com>
---
 drivers/cxl/core/hdm.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 3df10517a327..c729541bb7e1 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -327,10 +327,13 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
 	cxled->dpa_res = res;
 	cxled->skip = skipped;
 
-	if (resource_contains(&cxlds->pmem_res, res))
+	if (resource_size(&cxlds->pmem_res) &&
+	    resource_contains(&cxlds->pmem_res, res)) {
 		cxled->mode = CXL_DECODER_PMEM;
-	else if (resource_contains(&cxlds->ram_res, res))
+	} else if (resource_size(&cxlds->ram_res) &&
+		   resource_contains(&cxlds->ram_res, res)) {
 		cxled->mode = CXL_DECODER_RAM;
+	}
 	else {
 		dev_warn(dev, "decoder%d.%d: %pr mixed mode not supported\n",
 			 port->id, cxled->cxld.id, cxled->dpa_res);
-- 
2.17.1