[PATCH 2/7] cxl/memdev: Hold memdev lock during memdev poison injection/clear

[Li Ming]

CXL memdev poison injection/clearing debugfs interfaces are visible
before the CXL memdev endpoint initialization, If user accesses the
interfaces before cxlmd->endpoint updated, it is possible to access an
invalid endpoint in cxl_dpa_to_region().

Hold CXL memdev lock at the beginning of the interfaces, this blocks the
interfaces until CXL memdev probing completed.

The following patch will check the given endpoint validity in
cxl_dpa_to_region().

Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Li Ming <ming.li@xxxxxxxxxxxx>
---
 drivers/cxl/core/memdev.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 273c22118d3d..8ebaf9e96035 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -295,6 +295,7 @@ int cxl_inject_poison_locked(struct cxl_memdev *cxlmd, u64 dpa)
 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
 		return 0;
 
+	device_lock_assert(&cxlmd->dev);
 	lockdep_assert_held(&cxl_rwsem.dpa);
 	lockdep_assert_held(&cxl_rwsem.region);
 
@@ -331,6 +332,10 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
 {
 	int rc;
 
+	ACQUIRE(device_intr, devlock)(&cxlmd->dev);
+	if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
+		return rc;
+
 	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
 	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
 		return rc;
@@ -355,6 +360,7 @@ int cxl_clear_poison_locked(struct cxl_memdev *cxlmd, u64 dpa)
 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
 		return 0;
 
+	device_lock_assert(&cxlmd->dev);
 	lockdep_assert_held(&cxl_rwsem.dpa);
 	lockdep_assert_held(&cxl_rwsem.region);
 
@@ -400,6 +406,10 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
 {
 	int rc;
 
+	ACQUIRE(device_intr, devlock)(&cxlmd->dev);
+	if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
+		return rc;
+
 	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
 	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
 		return rc;

-- 
2.43.0