IB/uverbs: Fix lockdep warnings

Lockdep warns because uverbs is trying to take uobj->mutex when it
already holds that lock.  This is because there are really multiple
types of uobjs even though all of their locks are initialized in
common code.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 21 insertions, 11 deletions

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 0371806cf39..30923eb68ec 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -42,6 +42,13 @@
 
 #include "uverbs.h"
 
+static struct lock_class_key pd_lock_key;
+static struct lock_class_key mr_lock_key;
+static struct lock_class_key cq_lock_key;
+static struct lock_class_key qp_lock_key;
+static struct lock_class_key ah_lock_key;
+static struct lock_class_key srq_lock_key;
+
 #define INIT_UDATA(udata, ibuf, obuf, ilen, olen)                       \
         do {                                                            \
                 (udata)->inbuf  = (void __user *) (ibuf);               \
@@ -76,12 +83,13 @@
  */
 
 static void init_uobj(struct ib_uobject *uobj, u64 user_handle,
-                      struct ib_ucontext *context)
+                      struct ib_ucontext *context, struct lock_class_key *key)
 {
         uobj->user_handle = user_handle;
         uobj->context     = context;
         kref_init(&uobj->ref);
         init_rwsem(&uobj->mutex);
+        lockdep_set_class(&uobj->mutex, key);
         uobj->live        = 0;
 }
 
@@ -470,7 +478,7 @@ ssize_t ib_uverbs_alloc_pd(struct ib_uverbs_file *file,
         if (!uobj)
                 return -ENOMEM;
 
-        init_uobj(uobj, 0, file->ucontext);
+        init_uobj(uobj, 0, file->ucontext, &pd_lock_key);
         down_write(&uobj->mutex);
 
         pd = file->device->ib_dev->alloc_pd(file->device->ib_dev,
@@ -591,7 +599,7 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
         if (!obj)
                 return -ENOMEM;
 
-        init_uobj(&obj->uobject, 0, file->ucontext);
+        init_uobj(&obj->uobject, 0, file->ucontext, &mr_lock_key);
         down_write(&obj->uobject.mutex);
 
         /*
@@ -770,7 +778,7 @@ ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
         if (!obj)
                 return -ENOMEM;
 
-        init_uobj(&obj->uobject, cmd.user_handle, file->ucontext);
+        init_uobj(&obj->uobject, cmd.user_handle, file->ucontext, &cq_lock_key);
         down_write(&obj->uobject.mutex);
 
         if (cmd.comp_channel >= 0) {
@@ -1051,13 +1059,14 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
         if (!obj)
                 return -ENOMEM;
 
-        init_uobj(&obj->uevent.uobject, cmd.user_handle, file->ucontext);
+        init_uobj(&obj->uevent.uobject, cmd.user_handle, file->ucontext, &qp_lock_key);
         down_write(&obj->uevent.uobject.mutex);
 
+        srq = cmd.is_srq ? idr_read_srq(cmd.srq_handle, file->ucontext) : NULL;
         pd  = idr_read_pd(cmd.pd_handle, file->ucontext);
         scq = idr_read_cq(cmd.send_cq_handle, file->ucontext);
-        rcq = idr_read_cq(cmd.recv_cq_handle, file->ucontext);
-        srq = cmd.is_srq ? idr_read_srq(cmd.srq_handle, file->ucontext) : NULL;
+        rcq = cmd.recv_cq_handle == cmd.send_cq_handle ?
+                scq : idr_read_cq(cmd.recv_cq_handle, file->ucontext);
 
         if (!pd || !scq || !rcq || (cmd.is_srq && !srq)) {
                 ret = -EINVAL;
@@ -1125,7 +1134,8 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 
         put_pd_read(pd);
         put_cq_read(scq);
-        put_cq_read(rcq);
+        if (rcq != scq)
+                put_cq_read(rcq);
         if (srq)
                 put_srq_read(srq);
 
@@ -1150,7 +1160,7 @@ err_put:
                 put_pd_read(pd);
         if (scq)
                 put_cq_read(scq);
-        if (rcq)
+        if (rcq && rcq != scq)
                 put_cq_read(rcq);
         if (srq)
                 put_srq_read(srq);
@@ -1751,7 +1761,7 @@ ssize_t ib_uverbs_create_ah(struct ib_uverbs_file *file,
         if (!uobj)
                 return -ENOMEM;
 
-        init_uobj(uobj, cmd.user_handle, file->ucontext);
+        init_uobj(uobj, cmd.user_handle, file->ucontext, &ah_lock_key);
         down_write(&uobj->mutex);
 
         pd = idr_read_pd(cmd.pd_handle, file->ucontext);
@@ -1966,7 +1976,7 @@ ssize_t ib_uverbs_create_srq(struct ib_uverbs_file *file,
         if (!obj)
                 return -ENOMEM;
 
-        init_uobj(&obj->uobject, cmd.user_handle, file->ucontext);
+        init_uobj(&obj->uobject, cmd.user_handle, file->ucontext, &srq_lock_key);
         down_write(&obj->uobject.mutex);
 
         pd  = idr_read_pd(cmd.pd_handle, file->ucontext);