Hi,
+#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create)
Why do you start at 0x42 if you reserve the 0x40-0x4f range ?
No particular strong reason, just that using 42 was less boring than starting with 0x40.
+#define UDMABUF_CREATE_LIST _IOW('u', 0x43, struct udmabuf_create_list)
Where's the documentation ? :-)
Isn't it simple enough?
But, well, yes, I guess I can add some kerneldoc comments.
+static int udmabuf_vm_fault(struct vm_fault *vmf) +{
- struct vm_area_struct *vma = vmf->vma;
- struct udmabuf *ubuf = vma->vm_private_data;
- if (WARN_ON(vmf->pgoff >= ubuf->pagecount))
return VM_FAULT_SIGBUS;Just curious, when do you expect this to happen ?
It should not. If it actually happens it would be a bug somewhere, thats why the WARN_ON.
- struct udmabuf *ubuf;
- ubuf = kzalloc(sizeof(struct udmabuf), GFP_KERNEL);
sizeof(*ubuf)
Why? Should not make a difference ...
memfd = fget(list[i].memfd);if (!memfd)goto err_put_pages;if (!shmem_mapping(file_inode(memfd)->i_mapping))goto err_put_pages;seals = memfd_fcntl(memfd, F_GET_SEALS, 0);if (seals == -EINVAL ||(seals & SEALS_WANTED) != SEALS_WANTED ||(seals & SEALS_DENIED) != 0)goto err_put_pages;All these conditions will return -EINVAL. I'm not familiar with the memfd API, should some error conditions return a different error code to make them distinguishable by userspace ?
Hmm, I guess EBADFD would be reasonable in case the file handle isn't a memfd. Other suggestions?
I'll prepare a fixup patch series addressing most of the other review comments.
cheers, Gerd