cxl/core: Add locked variants of the poison inject and clear funcs

The core functions that validate and send inject and clear commands
to the memdev devices require holding both the dpa_rwsem and the
region_rwsem.

In preparation for another caller of these functions that must hold
the locks upon entry, split the work into a locked and unlocked pair.

Consideration was given to moving the locking to both callers,
however, the existing caller is not in the core (mem.c) and cannot
access the locks.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/1d601f586975195733984ca63d1b5789bbe8690f.1754290144.git.alison.schofield@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Author: AlisonSchofield

drivers/cxl/core/memdev.c

@@ -276,7 +276,7 @@ static int cxl_validate_poison_dpa(struct cxl_memdev *cxlmd, u64 dpa)
 	return 0;
 }
 
-int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
+int cxl_inject_poison_locked(struct cxl_memdev *cxlmd, u64 dpa)
 {
 	struct cxl_mailbox *cxl_mbox = &cxlmd->cxlds->cxl_mbox;
 	struct cxl_mbox_inject_poison inject;
@@ -288,13 +288,8 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
 		return 0;
 
-	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
-	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
-		return rc;
-
-	ACQUIRE(rwsem_read_intr, dpa_rwsem)(&cxl_rwsem.dpa);
-	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &dpa_rwsem)))
-		return rc;
+	lockdep_assert_held(&cxl_rwsem.dpa);
+	lockdep_assert_held(&cxl_rwsem.region);
 
 	rc = cxl_validate_poison_dpa(cxlmd, dpa);
 	if (rc)
@@ -324,9 +319,24 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
 
 	return 0;
 }
+
+int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
+{
+	int rc;
+
+	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
+	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
+		return rc;
+
+	ACQUIRE(rwsem_read_intr, dpa_rwsem)(&cxl_rwsem.dpa);
+	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &dpa_rwsem)))
+		return rc;
+
+	return cxl_inject_poison_locked(cxlmd, dpa);
+}
 EXPORT_SYMBOL_NS_GPL(cxl_inject_poison, "CXL");
 
-int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
+int cxl_clear_poison_locked(struct cxl_memdev *cxlmd, u64 dpa)
 {
 	struct cxl_mailbox *cxl_mbox = &cxlmd->cxlds->cxl_mbox;
 	struct cxl_mbox_clear_poison clear;
@@ -338,13 +348,8 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
 		return 0;
 
-	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
-	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
-		return rc;
-
-	ACQUIRE(rwsem_read_intr, dpa_rwsem)(&cxl_rwsem.dpa);
-	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &dpa_rwsem)))
-		return rc;
+	lockdep_assert_held(&cxl_rwsem.dpa);
+	lockdep_assert_held(&cxl_rwsem.region);
 
 	rc = cxl_validate_poison_dpa(cxlmd, dpa);
 	if (rc)
@@ -383,6 +388,21 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
 
 	return 0;
 }
+
+int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
+{
+	int rc;
+
+	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
+	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
+		return rc;
+
+	ACQUIRE(rwsem_read_intr, dpa_rwsem)(&cxl_rwsem.dpa);
+	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &dpa_rwsem)))
+		return rc;
+
+	return cxl_clear_poison_locked(cxlmd, dpa);
+}
 EXPORT_SYMBOL_NS_GPL(cxl_clear_poison, "CXL");
 
 static struct attribute *cxl_memdev_attributes[] = {

drivers/cxl/cxlmem.h

@@ -869,6 +869,8 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
 int cxl_trigger_poison_list(struct cxl_memdev *cxlmd);
 int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa);
 int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
+int cxl_inject_poison_locked(struct cxl_memdev *cxlmd, u64 dpa);
+int cxl_clear_poison_locked(struct cxl_memdev *cxlmd, u64 dpa);
 
 #ifdef CONFIG_CXL_EDAC_MEM_FEATURES
 int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd);