[PATCH v2] i2c: piix4: Fix a memory leak in the EFCH MMIO support

[PATCH v2] i2c: piix4: Fix a memory leak in the EFCH MMIO support

[Jean Delvare]

The recently added support for EFCH MMIO regions introduced a memory
leak in that code path. The leak is caused by the fact that
release_resource() merely removes the resource from the tree but does
not free its memory. We need to call release_mem_region() instead,
which does free the memory. As a nice side effect, this brings back
some symmetry between the legacy and MMIO paths.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 7c148722d074 ("i2c: piix4: Add EFCH MMIO support to region request and release")
Cc: Terry Bowman <terry.bowman@amd.com>
---
Changes since v1:
 * Added Reported-by and Tested-by tags for Yi Zhang
 * Removed local variable res as it is not needed

Technically this isn't the patch Yi Zhang tested, but I verified that
the generated binary code is the same, so it is safe to keep the
Tested-by tag.

 drivers/i2c/busses/i2c-piix4.c |   16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

--- linux-5.18.orig/drivers/i2c/busses/i2c-piix4.c	2022-06-21 16:17:35.040806444 +0200
+++ linux-5.18/drivers/i2c/busses/i2c-piix4.c	2022-06-21 23:07:52.605179908 +0200
@@ -161,7 +161,6 @@ static const char *piix4_aux_port_name_s
 
 struct sb800_mmio_cfg {
 	void __iomem *addr;
-	struct resource *res;
 	bool use_mmio;
 };
 
@@ -179,13 +178,11 @@ static int piix4_sb800_region_request(st
 				      struct sb800_mmio_cfg *mmio_cfg)
 {
 	if (mmio_cfg->use_mmio) {
-		struct resource *res;
 		void __iomem *addr;
 
-		res = request_mem_region_muxed(SB800_PIIX4_FCH_PM_ADDR,
-					       SB800_PIIX4_FCH_PM_SIZE,
-					       "sb800_piix4_smb");
-		if (!res) {
+		if (!request_mem_region_muxed(SB800_PIIX4_FCH_PM_ADDR,
+					      SB800_PIIX4_FCH_PM_SIZE,
+					      "sb800_piix4_smb")) {
 			dev_err(dev,
 				"SMBus base address memory region 0x%x already in use.\n",
 				SB800_PIIX4_FCH_PM_ADDR);
@@ -195,12 +192,12 @@ static int piix4_sb800_region_request(st
 		addr = ioremap(SB800_PIIX4_FCH_PM_ADDR,
 			       SB800_PIIX4_FCH_PM_SIZE);
 		if (!addr) {
-			release_resource(res);
+			release_mem_region(SB800_PIIX4_FCH_PM_ADDR,
+					   SB800_PIIX4_FCH_PM_SIZE);
 			dev_err(dev, "SMBus base address mapping failed.\n");
 			return -ENOMEM;
 		}
 
-		mmio_cfg->res = res;
 		mmio_cfg->addr = addr;
 
 		return 0;
@@ -222,7 +219,8 @@ static void piix4_sb800_region_release(s
 {
 	if (mmio_cfg->use_mmio) {
 		iounmap(mmio_cfg->addr);
-		release_resource(mmio_cfg->res);
+		release_mem_region(SB800_PIIX4_FCH_PM_ADDR,
+				   SB800_PIIX4_FCH_PM_SIZE);
 		return;
 	}
 


-- 
Jean Delvare
SUSE L3 Support

Re: [PATCH v2] i2c: piix4: Fix a memory leak in the EFCH MMIO support

[Wolfram Sang]

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On Wed, Jun 22, 2022 at 08:37:43AM +0200, Jean Delvare wrote:
> The recently added support for EFCH MMIO regions introduced a memory
> leak in that code path. The leak is caused by the fact that
> release_resource() merely removes the resource from the tree but does
> not free its memory. We need to call release_mem_region() instead,
> which does free the memory. As a nice side effect, this brings back
> some symmetry between the legacy and MMIO paths.
> 
> Signed-off-by: Jean Delvare <jdelvare@suse.de>
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Tested-by: Yi Zhang <yi.zhang@redhat.com>
> Fixes: 7c148722d074 ("i2c: piix4: Add EFCH MMIO support to region request and release")
> Cc: Terry Bowman <terry.bowman@amd.com>

Applied to for-current with Terry's tags given to v1, thanks!


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