IB/hfi1: Fix memory leak during unexpected shutdown

During an unexpected shutdown, references to tid_rb_node were NULL'ed out
without properly being released.

Fix this by calling clear_tid_node in the mmu notifier remove callback
rather than after these callbacks are called.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 31 insertions, 13 deletions

diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.c b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
index 8717e11fe3f5..64d26525435a 100644
--- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -87,13 +87,15 @@ static u32 find_phys_blocks(struct page **, unsigned, struct tid_pageset *);
 static int set_rcvarray_entry(struct file *, unsigned long, u32,
                               struct tid_group *, struct page **, unsigned);
 static int tid_rb_insert(void *, struct mmu_rb_node *);
+static void cacheless_tid_rb_remove(struct hfi1_filedata *fdata,
+                                    struct tid_rb_node *tnode);
 static void tid_rb_remove(void *, struct mmu_rb_node *);
 static int tid_rb_invalidate(void *, struct mmu_rb_node *);
 static int program_rcvarray(struct file *, unsigned long, struct tid_group *,
                             struct tid_pageset *, unsigned, u16, struct page **,
                             u32 *, unsigned *, unsigned *);
 static int unprogram_rcvarray(struct file *, u32, struct tid_group **);
-static void clear_tid_node(struct hfi1_filedata *, struct tid_rb_node *);
+static void clear_tid_node(struct hfi1_filedata *fd, struct tid_rb_node *node);
 
 static struct mmu_rb_ops tid_rb_ops = {
         .insert = tid_rb_insert,
@@ -899,14 +901,15 @@ static int unprogram_rcvarray(struct file *fp, u32 tidinfo,
         node = fd->entry_to_rb[rcventry];
         if (!node || node->rcventry != (uctxt->expected_base + rcventry))
                 return -EBADF;
+
+        if (grp)
+                *grp = node->grp;
+
         if (!fd->handler)
-                tid_rb_remove(fd, &node->mmu);
+                cacheless_tid_rb_remove(fd, node);
         else
                 hfi1_mmu_rb_remove(fd->handler, &node->mmu);
 
-        if (grp)
-                *grp = node->grp;
-        clear_tid_node(fd, node);
         return 0;
 }
 
@@ -943,6 +946,10 @@ static void clear_tid_node(struct hfi1_filedata *fd, struct tid_rb_node *node)
         kfree(node);
 }
 
+/*
+ * As a simple helper for hfi1_user_exp_rcv_free, this function deals with
+ * clearing nodes in the non-cached case.
+ */
 static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
                             struct exp_tid_set *set,
                             struct hfi1_filedata *fd)
@@ -962,17 +969,20 @@ static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
                                                           uctxt->expected_base];
                                 if (!node || node->rcventry != rcventry)
                                         continue;
-                                if (!fd->handler)
-                                        tid_rb_remove(fd, &node->mmu);
-                                else
-                                        hfi1_mmu_rb_remove(fd->handler,
-                                                           &node->mmu);
-                                clear_tid_node(fd, node);
+
+                                cacheless_tid_rb_remove(fd, node);
                         }
                 }
         }
 }
 
+/*
+ * Always return 0 from this function.  A non-zero return indicates that the
+ * remove operation will be called and that memory should be unpinned.
+ * However, the driver cannot unpin out from under PSM.  Instead, retain the
+ * memory (by returning 0) and inform PSM that the memory is going away.  PSM
+ * will call back later when it has removed the memory from its list.
+ */
 static int tid_rb_invalidate(void *arg, struct mmu_rb_node *mnode)
 {
         struct hfi1_filedata *fdata = arg;
@@ -1027,12 +1037,20 @@ static int tid_rb_insert(void *arg, struct mmu_rb_node *node)
         return 0;
 }
 
+static void cacheless_tid_rb_remove(struct hfi1_filedata *fdata,
+                                    struct tid_rb_node *tnode)
+{
+        u32 base = fdata->uctxt->expected_base;
+
+        fdata->entry_to_rb[tnode->rcventry - base] = NULL;
+        clear_tid_node(fdata, tnode);
+}
+
 static void tid_rb_remove(void *arg, struct mmu_rb_node *node)
 {
         struct hfi1_filedata *fdata = arg;
         struct tid_rb_node *tnode =
                 container_of(node, struct tid_rb_node, mmu);
-        u32 base = fdata->uctxt->expected_base;
 
-        fdata->entry_to_rb[tnode->rcventry - base] = NULL;
+        cacheless_tid_rb_remove(fdata, tnode);
 }