[PATCH RFC POC 36/50] nitro_enclaves: install the enclave descriptor when the ioctl returns

[Christian Brauner]

Rely on the fd exit path machinery.

Signed-off-by: Christian Brauner (Amutable) <brau...@kernel.org>
---
 drivers/virt/nitro_enclaves/ne_misc_dev.c | 33 ++++++++++++-------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c 
b/drivers/virt/nitro_enclaves/ne_misc_dev.c
index c91300a73f50..93c3f00f5443 100644
--- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -1589,7 +1589,7 @@ static const struct file_operations ne_enclave_fops = {
 static int ne_create_vm_ioctl(struct ne_pci_dev *ne_pci_dev, u64 __user 
*slot_uid)
 {
        struct ne_pci_dev_cmd_reply cmd_reply = {};
-       int enclave_fd = -1;
+       const struct fd_slot *enclave_fd = NULL;
        struct file *enclave_file = NULL;
        unsigned int i = 0;
        struct ne_enclave *ne_enclave = NULL;
@@ -1647,9 +1647,9 @@ static int ne_create_vm_ioctl(struct ne_pci_dev 
*ne_pci_dev, u64 __user *slot_ui
                goto free_cpumask;
        }
 
-       enclave_fd = get_unused_fd_flags(O_CLOEXEC);
-       if (enclave_fd < 0) {
-               rc = enclave_fd;
+       enclave_fd = fd_prepare(O_CLOEXEC);
+       if (IS_ERR(enclave_fd)) {
+               rc = PTR_ERR(enclave_fd);
 
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in getting unused fd [rc=%d]\n", rc);
@@ -1664,7 +1664,7 @@ static int ne_create_vm_ioctl(struct ne_pci_dev 
*ne_pci_dev, u64 __user *slot_ui
                dev_err_ratelimited(ne_misc_dev.this_device,
                                    "Error in anon inode get file [rc=%d]\n", 
rc);
 
-               goto put_fd;
+               goto free_cpumask;
        }
 
        rc = ne_do_request(pdev, SLOT_ALLOC,
@@ -1688,27 +1688,20 @@ static int ne_create_vm_ioctl(struct ne_pci_dev 
*ne_pci_dev, u64 __user *slot_ui
 
        list_add(&ne_enclave->enclave_list_entry, &ne_pci_dev->enclaves_list);
 
-       if (copy_to_user(slot_uid, &ne_enclave->slot_uid, 
sizeof(ne_enclave->slot_uid))) {
-               /*
-                * As we're holding the only reference to 'enclave_file', fput()
-                * will call ne_enclave_release() which will do a proper cleanup
-                * of all so far allocated resources, leaving only the unused fd
-                * for us to free.
-                */
-               fput(enclave_file);
-               put_unused_fd(enclave_fd);
+       fd_stage(enclave_fd, enclave_file);
 
+       /*
+        * The failed ioctl drops the descriptor and with it the only reference
+        * to 'enclave_file', so ne_enclave_release() does a proper cleanup of
+        * all so far allocated resources.
+        */
+       if (copy_to_user(slot_uid, &ne_enclave->slot_uid, 
sizeof(ne_enclave->slot_uid)))
                return -EFAULT;
-       }
-
-       fd_install(enclave_fd, enclave_file);
 
-       return enclave_fd;
+       return fd_prepare_fd(enclave_fd);
 
 put_file:
        fput(enclave_file);
-put_fd:
-       put_unused_fd(enclave_fd);
 free_cpumask:
        free_cpumask_var(ne_enclave->vcpu_ids);
        for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)

-- 
2.53.0