Introduce ibv_import_device(), it enable a process to get an ibv_context
that is associated with a given command FD that it owns.
A process is creating a device and then uses some of the Linux systems
calls to dup its 'cmd_fd' member and lets other process to obtain owning
on.
Once other process obtains the 'cmd_fd' it can call ibv_import_device()
which returns an ibv_contxet on the original RDMA device.
A detailed man page as part of this patch describes the expected usage
and flow.
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxxxx>
---
debian/libibverbs1.symbols | 1 +
libibverbs/device.c | 62 +++++++++++++++++++++++++++++++++++
libibverbs/driver.h | 2 ++
libibverbs/libibverbs.map.in | 1 +
libibverbs/man/CMakeLists.txt | 1 +
libibverbs/man/ibv_import_device.3.md | 48 +++++++++++++++++++++++++++
libibverbs/verbs.h | 5 +++
7 files changed, 120 insertions(+)
create mode 100644 libibverbs/man/ibv_import_device.3.md
diff --git a/debian/libibverbs1.symbols b/debian/libibverbs1.symbols
index bb7eac9..1ba5453 100644
--- a/debian/libibverbs1.symbols
+++ b/debian/libibverbs1.symbols
@@ -67,6 +67,7 @@ libibverbs.so.1 libibverbs1 #MINVER#
ibv_get_device_name@IBVERBS_1.1 1.1.6
ibv_get_pkey_index@IBVERBS_1.5 20
ibv_get_sysfs_path@IBVERBS_1.0 1.1.6
+ ibv_import_device@IBVERBS_1.10 31
ibv_init_ah_from_wc@IBVERBS_1.1 1.1.6
ibv_modify_qp@IBVERBS_1.0 1.1.6
ibv_modify_qp@IBVERBS_1.1 1.1.6
diff --git a/libibverbs/device.c b/libibverbs/device.c
index 4ef2a6a..e9c429a 100644
--- a/libibverbs/device.c
+++ b/libibverbs/device.c
@@ -382,6 +382,68 @@ LATEST_SYMVER_FUNC(ibv_open_device, 1_1, "IBVERBS_1.1",
return verbs_open_device(device, NULL);
}
+struct ibv_context *ibv_import_device(int cmd_fd)
+{
+ struct verbs_device *verbs_device = NULL;
+ struct verbs_context *context_ex;
+ struct ibv_device **dev_list;
+ struct ibv_context *ctx = NULL;
+ struct stat st;
+ int ret;
+ int i;
+
+ if (fstat(cmd_fd, &st) || !S_ISCHR(st.st_mode)) {
+ errno = EINVAL;
+ return NULL;
+ }
+
+ dev_list = ibv_get_device_list(NULL);
+ if (!dev_list) {
+ errno = ENODEV;
+ return NULL;
+ }
+
+ for (i = 0; dev_list[i]; ++i) {
+ if (verbs_get_device(dev_list[i])->sysfs->sysfs_cdev ==
+ st.st_rdev) {
+ verbs_device = verbs_get_device(dev_list[i]);
+ break;
+ }
+ }
+
+ if (!verbs_device) {
+ errno = ENODEV;
+ goto out;
+ }
+
+ if (!verbs_device->ops->import_context) {
+ errno = EOPNOTSUPP;
+ goto out;
+ }
+
+ /* In case the underlay cdev number was assigned in the meantime to
+ * other device as of some disassociate flow, the next call on the
+ * FD will end up with EIO (i.e. query_context command) and we should
+ * be safe from using the wrong device.
+ */
+ context_ex = verbs_device->ops->import_context(&verbs_device->device, cmd_fd);
+ if (!context_ex)
+ goto out;
+
+ set_lib_ops(context_ex);
+
+ context_ex->priv->imported = true;
+ ctx = &context_ex->context;
+ ret = ibv_cmd_alloc_async_fd(ctx);
+ if (ret) {
+ ibv_close_device(ctx);
+ ctx = NULL;
+ }
+out:
+ ibv_free_device_list(dev_list);
+ return ctx;
+}
+
void verbs_uninit_context(struct verbs_context *context_ex)
{
free(context_ex->priv);
diff --git a/libibverbs/driver.h b/libibverbs/driver.h
index a1b241b..48eace4 100644
--- a/libibverbs/driver.h
+++ b/libibverbs/driver.h
@@ -216,6 +216,8 @@ struct verbs_device_ops {
struct verbs_context *(*alloc_context)(struct ibv_device *device,
int cmd_fd,
void *private_data);
+ struct verbs_context *(*import_context)(struct ibv_device *device,
+ int cmd_fd);
struct verbs_device *(*alloc_device)(struct verbs_sysfs_dev *sysfs_dev);
void (*uninit_device)(struct verbs_device *device);
diff --git a/libibverbs/libibverbs.map.in b/libibverbs/libibverbs.map.in
index 61b6a80..be75717 100644
--- a/libibverbs/libibverbs.map.in
+++ b/libibverbs/libibverbs.map.in
@@ -133,6 +133,7 @@ IBVERBS_1.9 {
IBVERBS_1.10 {
global:
+ ibv_import_device;
ibv_query_ece;
ibv_set_ece;
} IBVERBS_1.9;
diff --git a/libibverbs/man/CMakeLists.txt b/libibverbs/man/CMakeLists.txt
index a9cf61e..06b5b49 100644
--- a/libibverbs/man/CMakeLists.txt
+++ b/libibverbs/man/CMakeLists.txt
@@ -37,6 +37,7 @@ rdma_man_pages(
ibv_get_device_name.3.md
ibv_get_pkey_index.3.md
ibv_get_srq_num.3.md
+ ibv_import_device.3.md
ibv_inc_rkey.3.md
ibv_modify_qp.3
ibv_modify_qp_rate_limit.3
diff --git a/libibverbs/man/ibv_import_device.3.md b/libibverbs/man/ibv_import_device.3.md
new file mode 100644
index 0000000..601b50a
--- /dev/null
+++ b/libibverbs/man/ibv_import_device.3.md
@@ -0,0 +1,48 @@
+---
+date: 2020-5-3
+footer: libibverbs
+header: "Libibverbs Programmer's Manual"
+layout: page
+license: 'Licensed under the OpenIB.org BSD license (FreeBSD Variant) - See COPYING.md'
+section: 3
+title: ibv_import_device
+---
+
+# NAME
+
+ibv_import_device - import a device from a given comamnd FD
+
+# SYNOPSIS
+
+```c
+#include <infiniband/verbs.h>
+
+struct ibv_context *ibv_import_device(int cmd_fd);
+
+```
+
+
+# DESCRIPTION
+
+**ibv_import_device()** returns an *ibv_context* pointer that is associated with the given
+*cmd_fd*.
+
+The *cmd_fd* is obtained from the ibv_context cmd_fd member, which must be dup'd (eg by dup(), SCM_RIGHTS, etc)
+before being passed to ibv_import_device().
+
+Once the *ibv_context* usage has been ended *ibv_close_device()* should be called.
+This call may cleanup whatever is needed/opposite of the import including closing the command FD.
+
+# RETURN VALUE
+
+**ibv_import_device()** returns a pointer to the allocated RDMA context, or NULL if the request fails.
+
+# SEE ALSO
+
+**ibv_open_device**(3),
+**ibv_close_device**(3),
+
+# AUTHOR
+
+Yishai Hadas <yishaih@xxxxxxxxxxxx>
+
diff --git a/libibverbs/verbs.h b/libibverbs/verbs.h
index f72c1ab..e1247b8 100644
--- a/libibverbs/verbs.h
+++ b/libibverbs/verbs.h
@@ -2242,6 +2242,11 @@ struct ibv_context *ibv_open_device(struct ibv_device *device);
int ibv_close_device(struct ibv_context *context);
/**
+ * ibv_import_device - Import device
+ */
+struct ibv_context *ibv_import_device(int cmd_fd);
+
+/**
* ibv_get_async_event - Get next async event
* @event: Pointer to use to return async event
*
--
1.8.3.1
