IB/core: Add legacy driver's user-data

In this phase, we don't want to change all the drivers to use
flexible driver's specific attributes. Therefore, we add two default
attributes: UHW_IN and UHW_OUT. These attributes are optional in some
methods and they encode the driver specific command data. We add
a function that extract this data and creates the legacy udata over
it.

Driver's data should start from UVERBS_UDATA_DRIVER_DATA_FLAG. This
turns on the first bit of the namespace, indicating this attribute
belongs to the driver's namespace.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

3 files changed, 96 insertions, 0 deletions

diff --git a/drivers/infiniband/core/uverbs_std_types.c b/drivers/infiniband/core/uverbs_std_types.c
index 5f90978bda8d..db66c18857e4 100644
--- a/drivers/infiniband/core/uverbs_std_types.c
+++ b/drivers/infiniband/core/uverbs_std_types.c
@@ -209,6 +209,46 @@ static int uverbs_hot_unplug_completion_event_file(struct ib_uobject_file *uobj_
         return 0;
 };
 
+/*
+ * This spec is used in order to pass information to the hardware driver in a
+ * legacy way. Every verb that could get driver specific data should get this
+ * spec.
+ */
+static const struct uverbs_attr_def uverbs_uhw_compat_in =
+        UVERBS_ATTR_PTR_IN_SZ(UVERBS_UHW_IN, 0, UA_FLAGS(UVERBS_ATTR_SPEC_F_MIN_SZ));
+static const struct uverbs_attr_def uverbs_uhw_compat_out =
+        UVERBS_ATTR_PTR_OUT_SZ(UVERBS_UHW_OUT, 0, UA_FLAGS(UVERBS_ATTR_SPEC_F_MIN_SZ));
+
+static void create_udata(struct uverbs_attr_bundle *ctx,
+                         struct ib_udata *udata)
+{
+        /*
+         * This is for ease of conversion. The purpose is to convert all drivers
+         * to use uverbs_attr_bundle instead of ib_udata.
+         * Assume attr == 0 is input and attr == 1 is output.
+         */
+        void __user *inbuf;
+        size_t inbuf_len = 0;
+        void __user *outbuf;
+        size_t outbuf_len = 0;
+        const struct uverbs_attr *uhw_in =
+                uverbs_attr_get(ctx, UVERBS_UHW_IN);
+        const struct uverbs_attr *uhw_out =
+                uverbs_attr_get(ctx, UVERBS_UHW_OUT);
+
+        if (!IS_ERR(uhw_in)) {
+                inbuf = uhw_in->ptr_attr.ptr;
+                inbuf_len = uhw_in->ptr_attr.len;
+        }
+
+        if (!IS_ERR(uhw_out)) {
+                outbuf = uhw_out->ptr_attr.ptr;
+                outbuf_len = uhw_out->ptr_attr.len;
+        }
+
+        INIT_UDATA_BUF_OR_NULL(udata, inbuf, outbuf, inbuf_len, outbuf_len);
+}
+
 DECLARE_UVERBS_OBJECT(uverbs_object_comp_channel,
                       UVERBS_OBJECT_COMP_CHANNEL,
                       &UVERBS_TYPE_ALLOC_FD(0,
diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
index 9a8d217cdc1d..759afa0621ea 100644
--- a/include/rdma/uverbs_ioctl.h
+++ b/include/rdma/uverbs_ioctl.h
@@ -36,6 +36,7 @@
 #include <rdma/uverbs_types.h>
 #include <linux/uaccess.h>
 #include <rdma/rdma_user_ioctl.h>
+#include <rdma/ib_user_ioctl_verbs.h>
 
 /*
  * =======================================
@@ -338,6 +339,51 @@ static inline bool uverbs_attr_is_valid(const struct uverbs_attr_bundle *attrs_b
                                             idx & ~UVERBS_ID_NS_MASK);
 }
 
+static inline const struct uverbs_attr *uverbs_attr_get(const struct uverbs_attr_bundle *attrs_bundle,
+                                                        u16 idx)
+{
+        u16 idx_bucket = idx >> UVERBS_ID_NS_SHIFT;
+
+        if (!uverbs_attr_is_valid(attrs_bundle, idx))
+                return ERR_PTR(-ENOENT);
+
+        return &attrs_bundle->hash[idx_bucket].attrs[idx & ~UVERBS_ID_NS_MASK];
+}
+
+static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
+                                 size_t idx, const void *from)
+{
+        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
+        u16 flags;
+
+        if (IS_ERR(attr))
+                return PTR_ERR(attr);
+
+        flags = attr->ptr_attr.flags | UVERBS_ATTR_F_VALID_OUTPUT;
+        return (!copy_to_user(attr->ptr_attr.ptr, from, attr->ptr_attr.len) &&
+                !put_user(flags, &attr->uattr->flags)) ? 0 : -EFAULT;
+}
+
+static inline int _uverbs_copy_from(void *to, size_t to_size,
+                                    const struct uverbs_attr_bundle *attrs_bundle,
+                                    size_t idx)
+{
+        const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
+
+        if (IS_ERR(attr))
+                return PTR_ERR(attr);
+
+        if (to_size <= sizeof(((struct ib_uverbs_attr *)0)->data))
+                memcpy(to, &attr->ptr_attr.data, attr->ptr_attr.len);
+        else if (copy_from_user(to, attr->ptr_attr.ptr, attr->ptr_attr.len))
+                return -EFAULT;
+
+        return 0;
+}
+
+#define uverbs_copy_from(to, attrs_bundle, idx)                               \
+        _uverbs_copy_from(to, sizeof(*(to)), attrs_bundle, idx)
+
 /* =================================================
  *       Definitions -> Specs infrastructure
  * =================================================
diff --git a/include/uapi/rdma/ib_user_ioctl_verbs.h b/include/uapi/rdma/ib_user_ioctl_verbs.h
index 78a2e5be4d6e..90f81eeca35b 100644
--- a/include/uapi/rdma/ib_user_ioctl_verbs.h
+++ b/include/uapi/rdma/ib_user_ioctl_verbs.h
@@ -33,6 +33,11 @@
 #ifndef IB_USER_IOCTL_VERBS_H
 #define IB_USER_IOCTL_VERBS_H
 
+#include <rdma/rdma_user_ioctl.h>
+
+#define UVERBS_UDATA_DRIVER_DATA_NS     1
+#define UVERBS_UDATA_DRIVER_DATA_FLAG   (1UL << UVERBS_ID_NS_SHIFT)
+
 enum uverbs_default_objects {
         UVERBS_OBJECT_DEVICE, /* No instances of DEVICE are allowed */
         UVERBS_OBJECT_PD,
@@ -50,5 +55,10 @@ enum uverbs_default_objects {
         UVERBS_OBJECT_LAST,
 };
 
+enum {
+        UVERBS_UHW_IN = UVERBS_UDATA_DRIVER_DATA_FLAG,
+        UVERBS_UHW_OUT,
+};
+
 #endif