cxl: Keep track of mm struct associated with a context
The mm_struct corresponding to the current task is acquired each time
an interrupt is raised. So to simplify the code, we only get the
mm_struct when attaching an AFU context to the process.
The mm_count reference is increased to ensure that the mm_struct can't
be freed. The mm_struct will be released when the context is detached.
A reference on mm_users is not kept to avoid a circular dependency if
the process mmaps its cxl mmio and forget to unmap before exiting.
The field glpid (pid of the group leader associated with the pid), of
the structure cxl_context, is removed because it's no longer useful.
Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 36bc213..4bcbf7a 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -482,8 +482,6 @@
unsigned int sst_size, sst_lru;
wait_queue_head_t wq;
- /* pid of the group leader associated with the pid */
- struct pid *glpid;
/* use mm context associated with this pid for ds faults */
struct pid *pid;
spinlock_t lock; /* Protects pending_irq_mask, pending_fault and fault_addr */
@@ -551,6 +549,8 @@
* CX4 only:
*/
struct list_head extra_irq_contexts;
+
+ struct mm_struct *mm;
};
struct cxl_service_layer_ops {
@@ -1012,4 +1012,10 @@
/* Unlock the contexts-lock if taken. Warn and force unlock otherwise */
void cxl_adapter_context_unlock(struct cxl *adapter);
+/* Increases the reference count to "struct mm_struct" */
+void cxl_context_mm_count_get(struct cxl_context *ctx);
+
+/* Decrements the reference count to "struct mm_struct" */
+void cxl_context_mm_count_put(struct cxl_context *ctx);
+
#endif