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
