vhost: add new eventfd copy ioctl

Signed-off-by: Pavel Boldin <pboldin@mirantis.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>

diff --git a/lib/librte_vhost/eventfd_link/eventfd_link.c b/lib/librte_vhost/eventfd_link/eventfd_link.c
index 7cbebd4..c54a938 100644 (file)
--- a/lib/librte_vhost/eventfd_link/eventfd_link.c
+++ b/lib/librte_vhost/eventfd_link/eventfd_link.c
@@ -77,6 +77,64 @@ fget_from_files(struct files_struct *files, unsigned fd)
        return file;
 }
 
+static long
+eventfd_link_ioctl_copy2(unsigned long arg)
+{
+       void __user *argp = (void __user *) arg;
+       struct task_struct *task_target = NULL;
+       struct file *file;
+       struct files_struct *files;
+       struct eventfd_copy2 eventfd_copy2;
+       long ret = -EFAULT;
+
+       if (copy_from_user(&eventfd_copy2, argp, sizeof(struct eventfd_copy2)))
+               goto out;
+
+       /*
+        * Find the task struct for the target pid
+        */
+       ret = -ESRCH;
+
+       task_target =
+               get_pid_task(find_vpid(eventfd_copy2.pid), PIDTYPE_PID);
+       if (task_target == NULL) {
+               pr_info("Unable to find pid %d\n", eventfd_copy2.pid);
+               goto out;
+       }
+
+       ret = -ESTALE;
+       files = get_files_struct(task_target);
+       if (files == NULL) {
+               pr_info("Failed to get target files struct\n");
+               goto out_task;
+       }
+
+       ret = -EBADF;
+       file = fget_from_files(files, eventfd_copy2.fd);
+       put_files_struct(files);
+
+       if (file == NULL) {
+               pr_info("Failed to get fd %d from target\n", eventfd_copy2.fd);
+               goto out_task;
+       }
+
+       /*
+        * Install the file struct from the target process into the
+        * newly allocated file desciptor of the source process.
+        */
+       ret = get_unused_fd_flags(eventfd_copy2.flags);
+       if (ret < 0) {
+               fput(file);
+               goto out_task;
+       }
+       fd_install(ret, file);
+
+out_task:
+       put_task_struct(task_target);
+out:
+       return ret;
+}
+
 static long
 eventfd_link_ioctl_copy(unsigned long arg)
 {
@@ -176,6 +234,9 @@ eventfd_link_ioctl(struct file *f, unsigned int ioctl, unsigned long arg)
        case EVENTFD_COPY:
                ret = eventfd_link_ioctl_copy(arg);
                break;
+       case EVENTFD_COPY2:
+               ret = eventfd_link_ioctl_copy2(arg);
+               break;
        }
 
        return ret;

diff --git a/lib/librte_vhost/eventfd_link/eventfd_link.h b/lib/librte_vhost/eventfd_link/eventfd_link.h
index ea619ec..5ebc20b 100644 (file)
--- a/lib/librte_vhost/eventfd_link/eventfd_link.h
+++ b/lib/librte_vhost/eventfd_link/eventfd_link.h
@@ -60,11 +60,6 @@
 #ifndef _EVENTFD_LINK_H_
 #define _EVENTFD_LINK_H_
 
-/*
- * ioctl to copy an fd entry in calling process to an fd in a target process
- */
-#define EVENTFD_COPY 1
-
 /*
  * arguements for the EVENTFD_COPY ioctl
  */
@@ -73,4 +68,27 @@ struct eventfd_copy {
        unsigned source_fd; /* fd in the calling pid */
        pid_t target_pid; /* pid of the target pid */
 };
+
+/*
+ * ioctl to copy an fd entry in calling process to an fd in a target process
+ * NOTE: this one should be
+ * #define EVENTFD_COPY _IOWR('D', 1, struct eventfd_copy) actually
+ */
+#define EVENTFD_COPY 1
+
+/*
+ * arguments for the EVENTFD_COPY2 ioctl
+ */
+struct eventfd_copy2 {
+       unsigned fd; /* fd to steal */
+       pid_t pid; /* pid of the process to steal from */
+       unsigned flags; /* flags to allocate new fd with */
+};
+
+/*
+ * ioctl to copy an fd entry from the target process into newly allocated
+ * fd in the calling process
+ */
+#define EVENTFD_COPY2 _IOW('D', 2, struct eventfd_copy2)
+
 #endif /* _EVENTFD_LINK_H_ */