KVM: VFIO: clean up control flow in kvm_vfio_file_add()

The struct file that this function fgets() is always passed to fput()
before returning, so use automatic cleanup via __free() to avoid several
jumps to the end of the function. Similarly, use a mutex guard to
completely remove the need to use gotos.

Signed-off-by: Carlos López <clopez@suse.de>
Reviewed-by: Alex Williamson <alex@shazbot.org>
Link: https://patch.msgid.link/20260313122040.1413091-4-clopez@suse.de
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 9f9acb66cc1e073eef3e303386f10e2fa7b8177b..2c91bad3333bb81de0d9edf94ce8547b7ff006a7 100644 (file)
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -144,33 +144,26 @@ static int kvm_vfio_file_add(struct kvm_device *dev, unsigned int fd)
 {
        struct kvm_vfio *kv = dev->private;
        struct kvm_vfio_file *kvf;
-       struct file *filp;
-       int ret = 0;
+       struct file *filp __free(fput) = NULL;
 
        filp = fget(fd);
        if (!filp)
                return -EBADF;
 
        /* Ensure the FD is a vfio FD. */
-       if (!kvm_vfio_file_is_valid(filp)) {
-               ret = -EINVAL;
-               goto out_fput;
-       }
+       if (!kvm_vfio_file_is_valid(filp))
+               return -EINVAL;
 
-       mutex_lock(&kv->lock);
+       guard(mutex)(&kv->lock);
 
        list_for_each_entry(kvf, &kv->file_list, node) {
-               if (kvf->file == filp) {
-                       ret = -EEXIST;
-                       goto out_unlock;
-               }
+               if (kvf->file == filp)
+                       return -EEXIST;
        }
 
        kvf = kzalloc_obj(*kvf, GFP_KERNEL_ACCOUNT);
-       if (!kvf) {
-               ret = -ENOMEM;
-               goto out_unlock;
-       }
+       if (!kvf)
+               return -ENOMEM;
 
        kvf->file = get_file(filp);
        list_add_tail(&kvf->node, &kv->file_list);
@@ -178,11 +171,7 @@ static int kvm_vfio_file_add(struct kvm_device *dev, unsigned int fd)
        kvm_vfio_file_set_kvm(kvf->file, dev->kvm);
        kvm_vfio_update_coherency(dev);
 
-out_unlock:
-       mutex_unlock(&kv->lock);
-out_fput:
-       fput(filp);
-       return ret;
+       return 0;
 }
 
 static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd)