+/*
+ * Transfer an interrupt request to userspace
+ *
+ * Unlike other requests this is assembled on demand, without a need
+ * to allocate a separate fuse_req structure.
+ *
+ * Called with fc->lock held, releases it
+ */
+static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req,
+ const struct iovec *iov, unsigned long nr_segs)
+{
+ struct fuse_copy_state cs;
+ struct fuse_in_header ih;
+ struct fuse_interrupt_in arg;
+ unsigned reqsize = sizeof(ih) + sizeof(arg);
+ int err;
+
+ list_del_init(&req->intr_entry);
+ req->intr_unique = fuse_get_unique(fc);
+ memset(&ih, 0, sizeof(ih));
+ memset(&arg, 0, sizeof(arg));
+ ih.len = reqsize;
+ ih.opcode = FUSE_INTERRUPT;
+ ih.unique = req->intr_unique;
+ arg.unique = req->in.h.unique;
+
+ spin_unlock(&fc->lock);
+ if (iov_length(iov, nr_segs) < reqsize)
+ return -EINVAL;
+
+ fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
+ err = fuse_copy_one(&cs, &ih, sizeof(ih));
+ if (!err)
+ err = fuse_copy_one(&cs, &arg, sizeof(arg));
+ fuse_copy_finish(&cs);
+
+ return err ? err : reqsize;
+}
+