[PATCH v3 1/8] iommu/amd: Refactor AMD IOMMU debugfs initial setup

Dheeraj Kumar Srivastava
2025-02-06T06:00:41Z

Rearrange initial setup of AMD IOMMU debugfs to segregate per IOMMU
setup and setup which is common for all IOMMUs. This ensures that common
debugfs paths (introduced in subsequent patches) are created only once
instead of being created for each IOMMU.

With the change, there is no need to use lock as amd_iommu_debugfs_setup()
will be called only once during AMD IOMMU initialization. So remove lock
acquisition in amd_iommu_debugfs_setup().

Signed-off-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
drivers/iommu/amd/amd_iommu.h | 4 ++--
drivers/iommu/amd/debugfs.c | 16 +++++++---------
drivers/iommu/amd/init.c | 5 ++---
3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 68debf5ee2d7..58308ed12d83 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -28,9 +28,9 @@ void *__init iommu_alloc_4k_pages(struct amd_iommu *iommu,
gfp_t gfp, size_t size);

#ifdef CONFIG_AMD_IOMMU_DEBUGFS
-void amd_iommu_debugfs_setup(struct amd_iommu *iommu);
+void amd_iommu_debugfs_setup(void);
#else
-static inline void amd_iommu_debugfs_setup(struct amd_iommu *iommu) {}
+static inline void amd_iommu_debugfs_setup(void) {}
#endif

/* Needed for interrupt remapping */
diff --git a/drivers/iommu/amd/debugfs.c b/drivers/iommu/amd/debugfs.c
index 545372fcc72f..ff9520e002be 100644
--- a/drivers/iommu/amd/debugfs.c
+++ b/drivers/iommu/amd/debugfs.c
@@ -13,20 +13,18 @@
#include "amd_iommu.h"

static struct dentry *amd_iommu_debugfs;
-static DEFINE_MUTEX(amd_iommu_debugfs_lock);

#define MAX_NAME_LEN 20

-void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
+void amd_iommu_debugfs_setup(void)
{
+ struct amd_iommu *iommu;
char name[MAX_NAME_LEN + 1];

- mutex_lock(&amd_iommu_debugfs_lock);
- if (!amd_iommu_debugfs)
- amd_iommu_debugfs = debugfs_create_dir("amd",
- iommu_debugfs_dir);
- mutex_unlock(&amd_iommu_debugfs_lock);
+ amd_iommu_debugfs = debugfs_create_dir("amd", iommu_debugfs_dir);

- snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu->index);
- iommu->debugfs = debugfs_create_dir(name, amd_iommu_debugfs);
+ for_each_iommu(iommu) {
+ snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu->index);
+ iommu->debugfs = debugfs_create_dir(name, amd_iommu_debugfs);
+ }
}
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index c5cd92edada0..1f0d422bfcbf 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3375,7 +3375,6 @@ int amd_iommu_enable_faulting(unsigned int cpu)
*/
static int __init amd_iommu_init(void)
{
- struct amd_iommu *iommu;
int ret;

ret = iommu_go_to_state(IOMMU_INITIALIZED);
@@ -3389,8 +3388,8 @@ static int __init amd_iommu_init(void)
}
#endif

- for_each_iommu(iommu)
- amd_iommu_debugfs_setup(iommu);
+ if (!ret)
+ amd_iommu_debugfs_setup();

return ret;
}
--
2.25.1