Re: [PATCH 1/9] mm: Introduce new vm_insert_range API

Souptick Joarder
2018-11-19T17:41:54Z

On Mon, Nov 19, 2018 at 9:56 PM Mike Rapoport <rppt@linux.ibm.com> wrote:
>
> On Mon, Nov 19, 2018 at 08:43:09PM +0530, Souptick Joarder wrote:
> > Hi Mike,
> >
> > On Sat, Nov 17, 2018 at 8:07 PM Matthew Wilcox <willy@infradead.org> wrote:
> > >
> > > On Sat, Nov 17, 2018 at 12:26:38PM +0530, Souptick Joarder wrote:
> > > > On Fri, Nov 16, 2018 at 11:59 PM Mike Rapoport <rppt@linux.ibm.com> wrote:
> > > > > > + * vm_insert_range - insert range of kernel pages into user vma
> > > > > > + * @vma: user vma to map to
> > > > > > + * @addr: target user address of this page
> > > > > > + * @pages: pointer to array of source kernel pages
> > > > > > + * @page_count: no. of pages need to insert into user vma
> > > > > > + *
> > > > > > + * This allows drivers to insert range of kernel pages they've allocated
> > > > > > + * into a user vma. This is a generic function which drivers can use
> > > > > > + * rather than using their own way of mapping range of kernel pages into
> > > > > > + * user vma.
> > > > >
> > > > > Please add the return value and context descriptions.
> > > > >
> > > >
> > > > Sure I will wait for some time to get additional review comments and
> > > > add all of those requested changes in v2.
> > >
> > > You could send your proposed wording now which might remove the need
> > > for a v3 if we end up arguing about the wording.
> >
> > Does this description looks good ?
> >
> > /**
> > * vm_insert_range - insert range of kernel pages into user vma
> > * @vma: user vma to map to
> > * @addr: target user address of this page
> > * @pages: pointer to array of source kernel pages
> > * @page_count: number of pages need to insert into user vma
> > *
> > * This allows drivers to insert range of kernel pages they've allocated
> > * into a user vma. This is a generic function which drivers can use
> > * rather than using their own way of mapping range of kernel pages into
> > * user vma.
> > *
> > * Context - Process context. Called by mmap handlers.
>
> Context:
>
> > * Return - int error value
>
> Return:
>
> > * 0 - OK
> > * -EINVAL - Invalid argument
> > * -ENOMEM - No memory
> > * -EFAULT - Bad address
> > * -EBUSY - Device or resource busy
>
> I don't think that elaborate description of error values is needed, just "0
> on success and error code otherwise" would be sufficient.

/**
* vm_insert_range - insert range of kernel pages into user vma
* @vma: user vma to map to
* @addr: target user address of this page
* @pages: pointer to array of source kernel pages
* @page_count: number of pages need to insert into user vma
*
* This allows drivers to insert range of kernel pages they've allocated
* into a user vma. This is a generic function which drivers can use
* rather than using their own way of mapping range of kernel pages into
* user vma.
*
* Context: Process context. Called by mmap handlers.
* Return: 0 on success and error code otherwise
*/