On Wed, Apr 28, 2021 at 03:35:43PM +0000, Liam Howlett wrote: > Many places in the kernel use find_vma() to get a vma and then check the > start address of the vma to ensure the next vma was not returned. > > Other places use the find_vma_intersection() call with add, addr + 1 as > the range; looking for just the vma at a specific address. > > The third use of find_vma() is by developers who do not know that the > function starts searching at the provided address upwards for the next > vma. This results in a bug that is often overlooked for a long time. > > Adding the new vma_lookup() function will allow for cleaner code by > removing the find_vma() calls which check limits, making > find_vma_intersection() calls of a single address to be shorter, and > potentially reduce the incorrect uses of find_vma(). > > Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> This seems like a good API to have, and I agree it's less error prone than having every caller check the vma->vm_start address. Minor nitpick, I would prefer if the implementation used find_vma() and then checked the vma->vm_start address - I don't like using [i, i+1) intervals to implement stabbing queries. But other than that, I think this (and the other patches adding corresponding call sites) is safe for merging. -- Michel "walken" Lespinasse
