IB/uverbs: Export ib_umem_get()/ib_umem_release() to modules

Export ib_umem_get()/ib_umem_release() and put low-level drivers in
control of when to call ib_umem_get() to pin and DMA map userspace,
rather than always calling it in ib_uverbs_reg_mr() before calling the
low-level driver's reg_user_mr method.

Also move these functions to be in the ib_core module instead of
ib_uverbs, so that driver modules using them do not depend on
ib_uverbs.

This has a number of advantages:
 - It is better design from the standpoint of making generic code a
   library that can be used or overridden by device-specific code as
   the details of specific devices dictate.
 - Drivers that do not need to pin userspace memory regions do not
   need to take the performance hit of calling ib_mem_get().  For
   example, although I have not tried to implement it in this patch,
   the ipath driver should be able to avoid pinning memory and just
   use copy_{to,from}_user() to access userspace memory regions.
 - Buffers that need special mapping treatment can be identified by
   the low-level driver.  For example, it may be possible to solve
   some Altix-specific memory ordering issues with mthca CQs in
   userspace by mapping CQ buffers with extra flags.
 - Drivers that need to pin and DMA map userspace memory for things
   other than memory regions can use ib_umem_get() directly, instead
   of hacks using extra parameters to their reg_phys_mr method.  For
   example, the mlx4 driver that is pending being merged needs to pin
   and DMA map QP and CQ buffers, but it does not need to create a
   memory key for these buffers.  So the cleanest solution is for mlx4
   to call ib_umem_get() in the create_qp and create_cq methods.

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

1 files changed, 20 insertions, 40 deletions

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index bab66769be1..01d70084aeb 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2005 Topspin Communications.  All rights reserved.
- * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
+ * Copyright (c) 2005, 2006, 2007 Cisco Systems.  All rights reserved.
  * Copyright (c) 2005 PathScale, Inc.  All rights reserved.
  * Copyright (c) 2006 Mellanox Technologies.  All rights reserved.
  *
@@ -295,6 +295,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
         INIT_LIST_HEAD(&ucontext->qp_list);
         INIT_LIST_HEAD(&ucontext->srq_list);
         INIT_LIST_HEAD(&ucontext->ah_list);
+        ucontext->closing = 0;
 
         resp.num_comp_vectors = file->device->num_comp_vectors;
 
@@ -573,7 +574,7 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
         struct ib_uverbs_reg_mr      cmd;
         struct ib_uverbs_reg_mr_resp resp;
         struct ib_udata              udata;
-        struct ib_umem_object       *obj;
+        struct ib_uobject           *uobj;
         struct ib_pd                *pd;
         struct ib_mr                *mr;
         int                          ret;
@@ -599,35 +600,21 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
             !(cmd.access_flags & IB_ACCESS_LOCAL_WRITE))
                 return -EINVAL;
 
-        obj = kmalloc(sizeof *obj, GFP_KERNEL);
-        if (!obj)
+        uobj = kmalloc(sizeof *uobj, GFP_KERNEL);
+        if (!uobj)
                 return -ENOMEM;
 
-        init_uobj(&obj->uobject, 0, file->ucontext, &mr_lock_key);
-        down_write(&obj->uobject.mutex);
-
-        /*
-         * We ask for writable memory if any access flags other than
-         * "remote read" are set.  "Local write" and "remote write"
-         * obviously require write access.  "Remote atomic" can do
-         * things like fetch and add, which will modify memory, and
-         * "MW bind" can change permissions by binding a window.
-         */
-        ret = ib_umem_get(file->device->ib_dev, &obj->umem,
-                          (void *) (unsigned long) cmd.start, cmd.length,
-                          !!(cmd.access_flags & ~IB_ACCESS_REMOTE_READ));
-        if (ret)
-                goto err_free;
-
-        obj->umem.virt_base = cmd.hca_va;
+        init_uobj(uobj, 0, file->ucontext, &mr_lock_key);
+        down_write(&uobj->mutex);
 
         pd = idr_read_pd(cmd.pd_handle, file->ucontext);
         if (!pd) {
                 ret = -EINVAL;
-                goto err_release;
+                goto err_free;
         }
 
-        mr = pd->device->reg_user_mr(pd, &obj->umem, cmd.access_flags, &udata);
+        mr = pd->device->reg_user_mr(pd, cmd.start, cmd.length, cmd.hca_va,
+                                     cmd.access_flags, &udata);
         if (IS_ERR(mr)) {
                 ret = PTR_ERR(mr);
                 goto err_put;
@@ -635,19 +622,19 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
 
         mr->device  = pd->device;
         mr->pd      = pd;
-        mr->uobject = &obj->uobject;
+        mr->uobject = uobj;
         atomic_inc(&pd->usecnt);
         atomic_set(&mr->usecnt, 0);
 
-        obj->uobject.object = mr;
-        ret = idr_add_uobj(&ib_uverbs_mr_idr, &obj->uobject);
+        uobj->object = mr;
+        ret = idr_add_uobj(&ib_uverbs_mr_idr, uobj);
         if (ret)
                 goto err_unreg;
 
         memset(&resp, 0, sizeof resp);
         resp.lkey      = mr->lkey;
         resp.rkey      = mr->rkey;
-        resp.mr_handle = obj->uobject.id;
+        resp.mr_handle = uobj->id;
 
         if (copy_to_user((void __user *) (unsigned long) cmd.response,
                          &resp, sizeof resp)) {
@@ -658,17 +645,17 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
         put_pd_read(pd);
 
         mutex_lock(&file->mutex);
-        list_add_tail(&obj->uobject.list, &file->ucontext->mr_list);
+        list_add_tail(&uobj->list, &file->ucontext->mr_list);
         mutex_unlock(&file->mutex);
 
-        obj->uobject.live = 1;
+        uobj->live = 1;
 
-        up_write(&obj->uobject.mutex);
+        up_write(&uobj->mutex);
 
         return in_len;
 
 err_copy:
-        idr_remove_uobj(&ib_uverbs_mr_idr, &obj->uobject);
+        idr_remove_uobj(&ib_uverbs_mr_idr, uobj);
 
 err_unreg:
         ib_dereg_mr(mr);
@@ -676,11 +663,8 @@ err_unreg:
 err_put:
         put_pd_read(pd);
 
-err_release:
-        ib_umem_release(file->device->ib_dev, &obj->umem);
-
 err_free:
-        put_uobj_write(&obj->uobject);
+        put_uobj_write(uobj);
         return ret;
 }
 
@@ -691,7 +675,6 @@ ssize_t ib_uverbs_dereg_mr(struct ib_uverbs_file *file,
         struct ib_uverbs_dereg_mr cmd;
         struct ib_mr             *mr;
         struct ib_uobject        *uobj;
-        struct ib_umem_object    *memobj;
         int                       ret = -EINVAL;
 
         if (copy_from_user(&cmd, buf, sizeof cmd))
@@ -701,8 +684,7 @@ ssize_t ib_uverbs_dereg_mr(struct ib_uverbs_file *file,
         if (!uobj)
                 return -EINVAL;
 
-        memobj = container_of(uobj, struct ib_umem_object, uobject);
-        mr     = uobj->object;
+        mr = uobj->object;
 
         ret = ib_dereg_mr(mr);
         if (!ret)
@@ -719,8 +701,6 @@ ssize_t ib_uverbs_dereg_mr(struct ib_uverbs_file *file,
         list_del(&uobj->list);
         mutex_unlock(&file->mutex);
 
-        ib_umem_release(file->device->ib_dev, &memobj->umem);
-
         put_uobj(uobj);
 
         return in_len;