* Michel Lespinasse <michel@xxxxxxxxxxxxxx> [210501 01:04]: > 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. Okay, I will make that change. > > But other than that, I think this (and the other patches adding > corresponding call sites) is safe for merging. > Thanks, Liam
