[PATCH V5 1/4] perf/x86/intel/uncore: Fix iounmap() leak on global_init failure

[Zide Chen <zide.chen@intel.com>]

Kernel test robot reported:

Unverified Error/Warning (likely false positive, kindly check if
interested):
    arch/x86/events/intel/uncore_discovery.c:293:2-8:
    ERROR: missing iounmap; ioremap on line 288 and execution via
    conditional on line 292

If domain->global_init() fails in __parse_discovery_table(), the
ioremap'ed MMIO region is not released before returning, resulting
in an MMIO mapping leak.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: b575fc0e3357 ("perf/x86/intel/uncore: Add domain global init callback")
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
---
V2:
- As suggested by Markus, add an `out` label and use goto-based error
  handling to reduce duplicated iounmap() code.
- Add the original warning from the kernel test robot to the commit message.
- Trivial rewording of the commit message.

V3:
- Add Reviewed-by tag.
---
 arch/x86/events/intel/uncore_discovery.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index 1b1a6b221048..6a4e892cd525 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -264,6 +264,7 @@ static int __parse_discovery_table(struct uncore_discovery_domain *domain,
 	struct uncore_unit_discovery unit;
 	void __iomem *io_addr;
 	unsigned long size;
+	int ret = 0;
 	int i;
 
 	size = UNCORE_DISCOVERY_GLOBAL_MAP_SIZE;
@@ -273,21 +274,23 @@ static int __parse_discovery_table(struct uncore_discovery_domain *domain,
 
 	/* Read Global Discovery State */
 	memcpy_fromio(&global, io_addr, sizeof(struct uncore_global_discovery));
+	iounmap(io_addr);
+
 	if (uncore_discovery_invalid_unit(global)) {
 		pr_info("Invalid Global Discovery State: 0x%llx 0x%llx 0x%llx\n",
 			global.table1, global.ctl, global.table3);
-		iounmap(io_addr);
 		return -EINVAL;
 	}
-	iounmap(io_addr);
 
 	size = (1 + global.max_units) * global.stride * 8;
 	io_addr = ioremap(addr, size);
 	if (!io_addr)
 		return -ENOMEM;
 
-	if (domain->global_init && domain->global_init(global.ctl))
-		return -ENODEV;
+	if (domain->global_init && domain->global_init(global.ctl)) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	/* Parsing Unit Discovery State */
 	for (i = 0; i < global.max_units; i++) {
@@ -307,8 +310,10 @@ static int __parse_discovery_table(struct uncore_discovery_domain *domain,
 	}
 
 	*parsed = true;
+
+out:
 	iounmap(io_addr);
-	return 0;
+	return ret;
 }
 
 static int parse_discovery_table(struct uncore_discovery_domain *domain,
-- 
2.53.0