Messages in this thread | | | Date | Thu, 7 Feb 2019 08:47:39 -0800 | From | Matthew Wilcox <> | Subject | Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API |
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On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > Just thought to take opinion for documentation before placing it in v3. > Does it looks fine ? > > +/** > + * __vm_insert_range - insert range of kernel pages into user vma > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * @offset: user's requested vm_pgoff > + * > + * This allow drivers to insert range of kernel pages into a user vma. > + * > + * Return: 0 on success and error code otherwise. > + */ > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num, unsigned long offset)
For static functions, I prefer to leave off the second '*', ie make it formatted like a docbook comment, but not be processed like a docbook comment. That avoids cluttering the html with descriptions of internal functions that people can't actually call.
> +/** > + * vm_insert_range - insert range of kernel pages starts with non zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Maps an object consisting of `num' `pages', catering for the user's
Rather than using `num', you should use @num.
> + * requested vm_pgoff > + * > + * If we fail to insert any page into the vma, the function will return > + * immediately leaving any previously inserted pages present. Callers > + * from the mmap handler may immediately return the error as their caller > + * will destroy the vma, removing any successfully inserted pages. Other > + * callers should make their own arrangements for calling unmap_region(). > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > > > +/** > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to
But vm_pgoff isn't a parameter, so it's misleading to format it as such.
> + * 0. This function is intended for the drivers that did not consider > + * @vm_pgoff. > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > + unsigned long num)
I don't think we should call it 'buggy'. 'zero' would make more sense as a suffix.
Given how this interface has evolved, I'm no longer sure than 'vm_insert_range' makes sense as the name for it. Is it perhaps 'vm_map_object' or 'vm_map_pages'?
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