| Message ID | 20240708165714.3401377-2-martin.oliveira@eideticom.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Enable P2PDMA in Userspace RDMA | expand |
On Mon, Jul 08, 2024 at 10:57:12AM -0600, Martin Oliveira wrote: > The .page_mkwrite operator of kernfs just calls file_update_time(). > This is the same behaviour that the fault code does if .page_mkwrite is > not set. > > Furthermore, having the page_mkwrite() operator causes > writable_file_mapping_allowed() to fail due to > vma_needs_dirty_tracking() on the gup flow, which is a pre-requisite for > enabling P2PDMA over RDMA. > > There are no users of .page_mkwrite and no known valid use cases, so > just remove the .page_mkwrite from kernfs_ops and WARN if an mmap() > implementation sets .page_mkwrite. > > Co-developed-by: Logan Gunthorpe <logang@deltatee.com> > Signed-off-by: Logan Gunthorpe <logang@deltatee.com> > Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com> > --- > fs/kernfs/file.c | 40 +++++++++++----------------------------- > 1 file changed, 11 insertions(+), 29 deletions(-) Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On Mon, Jul 08, 2024 at 10:57:12AM -0600, Martin Oliveira wrote: > - /* > - * It is not possible to successfully wrap close. > - * So error if someone is trying to use close. > - */ > - if (vma->vm_ops && vma->vm_ops->close) > - goto out_put; > + if (vma->vm_ops) { > + /* > + * It is not possible to successfully wrap close. > + * So error if someone is trying to use close. > + */ > + if (vma->vm_ops->close) > + goto out_put; > + > + if (WARN_ON_ONCE(vma->vm_ops->page_mkwrite)) > + goto out_put; > + } This is stupid. Warn for both or neither.
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 8502ef68459b..fb2b77bf0c04 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -386,28 +386,6 @@ static vm_fault_t kernfs_vma_fault(struct vm_fault *vmf) return ret; } -static vm_fault_t kernfs_vma_page_mkwrite(struct vm_fault *vmf) -{ - struct file *file = vmf->vma->vm_file; - struct kernfs_open_file *of = kernfs_of(file); - vm_fault_t ret; - - if (!of->vm_ops) - return VM_FAULT_SIGBUS; - - if (!kernfs_get_active(of->kn)) - return VM_FAULT_SIGBUS; - - ret = 0; - if (of->vm_ops->page_mkwrite) - ret = of->vm_ops->page_mkwrite(vmf); - else - file_update_time(file); - - kernfs_put_active(of->kn); - return ret; -} - static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr, void *buf, int len, int write) { @@ -432,7 +410,6 @@ static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr, static const struct vm_operations_struct kernfs_vm_ops = { .open = kernfs_vma_open, .fault = kernfs_vma_fault, - .page_mkwrite = kernfs_vma_page_mkwrite, .access = kernfs_vma_access, }; @@ -475,12 +452,17 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma) if (of->mmapped && of->vm_ops != vma->vm_ops) goto out_put; - /* - * It is not possible to successfully wrap close. - * So error if someone is trying to use close. - */ - if (vma->vm_ops && vma->vm_ops->close) - goto out_put; + if (vma->vm_ops) { + /* + * It is not possible to successfully wrap close. + * So error if someone is trying to use close. + */ + if (vma->vm_ops->close) + goto out_put; + + if (WARN_ON_ONCE(vma->vm_ops->page_mkwrite)) + goto out_put; + } rc = 0; if (!of->mmapped) {