IB/hfi1: Notify remove MMU/RB callback of calling context

Tell the remove MMU/RB callback if it's being called as
part of a memory invalidation or not. This can be important
in preventing a deadlock if the remove callback attempts to
take the map_sem semaphore because the kernel's MMU
invalidation functions have already taken it.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

3 files changed, 11 insertions, 10 deletions

diff --git a/drivers/staging/rdma/hfi1/mmu_rb.c b/drivers/staging/rdma/hfi1/mmu_rb.c
index a3515d7f6354..29d6d3e0694d 100644
--- a/drivers/staging/rdma/hfi1/mmu_rb.c
+++ b/drivers/staging/rdma/hfi1/mmu_rb.c
@@ -122,7 +122,7 @@ void hfi1_mmu_rb_unregister(struct rb_root *root)
                         rbnode = rb_entry(node, struct mmu_rb_node, node);
                         rb_erase(node, root);
                         if (handler->ops->remove)
-                                handler->ops->remove(root, rbnode);
+                                handler->ops->remove(root, rbnode, false);
                 }
         }
 
@@ -196,12 +196,12 @@ static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 }
 
 static void __mmu_rb_remove(struct mmu_rb_handler *handler,
-                            struct mmu_rb_node *node)
+                            struct mmu_rb_node *node, bool arg)
 {
         /* Validity of handler and node pointers has been checked by caller. */
         rb_erase(&node->node, handler->root);
         if (handler->ops->remove)
-                handler->ops->remove(handler->root, node);
+                handler->ops->remove(handler->root, node, arg);
 }
 
 struct mmu_rb_node *hfi1_mmu_rb_search(struct rb_root *root, unsigned long addr,
@@ -230,7 +230,7 @@ void hfi1_mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node)
                 return;
 
         spin_lock_irqsave(&handler->lock, flags);
-        __mmu_rb_remove(handler, node);
+        __mmu_rb_remove(handler, node, false);
         spin_unlock_irqrestore(&handler->lock, flags);
 }
 
@@ -299,7 +299,7 @@ static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
                 naddr = node->addr;
                 nlen = node->len;
                 if (handler->ops->invalidate(root, node))
-                        __mmu_rb_remove(handler, node);
+                        __mmu_rb_remove(handler, node, true);
 
                 /*
                  * The next address to be looked up is computed based
diff --git a/drivers/staging/rdma/hfi1/mmu_rb.h b/drivers/staging/rdma/hfi1/mmu_rb.h
index 9fe1076ab39d..fdd978757b90 100644
--- a/drivers/staging/rdma/hfi1/mmu_rb.h
+++ b/drivers/staging/rdma/hfi1/mmu_rb.h
@@ -59,7 +59,7 @@ struct mmu_rb_ops {
         int (*compare)(struct mmu_rb_node *, unsigned long,
                        unsigned long);
         int (*insert)(struct rb_root *, struct mmu_rb_node *);
-        void (*remove)(struct rb_root *, struct mmu_rb_node *);
+        void (*remove)(struct rb_root *, struct mmu_rb_node *, bool);
         int (*invalidate)(struct rb_root *, struct mmu_rb_node *);
 };
 
diff --git a/drivers/staging/rdma/hfi1/user_exp_rcv.c b/drivers/staging/rdma/hfi1/user_exp_rcv.c
index b0b193f30fac..1d971c0fedd6 100644
--- a/drivers/staging/rdma/hfi1/user_exp_rcv.c
+++ b/drivers/staging/rdma/hfi1/user_exp_rcv.c
@@ -89,7 +89,7 @@ static int set_rcvarray_entry(struct file *, unsigned long, u32,
 static inline int mmu_addr_cmp(struct mmu_rb_node *, unsigned long,
                                unsigned long);
 static int mmu_rb_insert(struct rb_root *, struct mmu_rb_node *);
-static void mmu_rb_remove(struct rb_root *, struct mmu_rb_node *);
+static void mmu_rb_remove(struct rb_root *, struct mmu_rb_node *, bool);
 static int mmu_rb_invalidate(struct rb_root *, struct mmu_rb_node *);
 static int program_rcvarray(struct file *, unsigned long, struct tid_group *,
                             struct tid_pageset *, unsigned, u16, struct page **,
@@ -897,7 +897,7 @@ static int unprogram_rcvarray(struct file *fp, u32 tidinfo,
         if (!node || node->rcventry != (uctxt->expected_base + rcventry))
                 return -EBADF;
         if (HFI1_CAP_IS_USET(TID_UNMAP))
-                mmu_rb_remove(&fd->tid_rb_root, &node->mmu);
+                mmu_rb_remove(&fd->tid_rb_root, &node->mmu, false);
         else
                 hfi1_mmu_rb_remove(&fd->tid_rb_root, &node->mmu);
 
@@ -962,7 +962,7 @@ static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
                                         continue;
                                 if (HFI1_CAP_IS_USET(TID_UNMAP))
                                         mmu_rb_remove(&fd->tid_rb_root,
-                                                      &node->mmu);
+                                                      &node->mmu, false);
                                 else
                                         hfi1_mmu_rb_remove(&fd->tid_rb_root,
                                                            &node->mmu);
@@ -1039,7 +1039,8 @@ static int mmu_rb_insert(struct rb_root *root, struct mmu_rb_node *node)
         return 0;
 }
 
-static void mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node)
+static void mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node,
+                          bool notifier)
 {
         struct hfi1_filedata *fdata =
                 container_of(root, struct hfi1_filedata, tid_rb_root);