On Wed, Nov 21, 2018 at 04:19:11AM -0700, William Kucharski wrote: > Could you add a line to the description explicitly stating that a failure > to insert any page in the range will fail the entire routine, something > like: > > > * 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. > > * > > * A failure to insert any page in the range will fail the call as a whole. > > It's obvious when reading the code, but it would be self-documenting to > state it outright. It's probably better to be more explicit and answer Randy's question: * 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(). Although unmap_region() is static so there clearly isn't any code in the kernel today other than in mmap handlers (or fault handlers) that needs to insert pages into a VMA.
