Messages in this thread Patch in this message | | | Date | Thu, 20 May 2021 20:32:32 -0700 | From | Davidlohr Bueso <> | Subject | Re: [PATCH 01/22] mm: Add vma_lookup() |
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On Mon, 10 May 2021, 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@Oracle.com> >--- > include/linux/mm.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > >diff --git a/include/linux/mm.h b/include/linux/mm.h >index 25b9041f9925..5f2a15e702ff 100644 >--- a/include/linux/mm.h >+++ b/include/linux/mm.h >@@ -2689,6 +2689,24 @@ static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * m > return vma; > }
While at it can we clean up find_vma_intersection? I'm not particularly user/fan of checkpatch.pl, but this one is kind of ridiculous.
Thanks, Davidlohr
diff --git a/include/linux/mm.h b/include/linux/mm.h index c274f75efcf9..16eddedf783f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2678,9 +2678,14 @@ extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long add extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr, struct vm_area_struct **pprev);
-/* Look up the first VMA which intersects the interval start_addr..end_addr-1, - NULL if none. Assume start_addr < end_addr. */ -static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr) +/* + * Look up the first VMA which intersects the interval start_addr..end_addr-1, + * NULL if none. Assume start_addr < end_addr. + */ +static inline +struct vm_area_struct *find_vma_intersection(struct mm_struct * mm, + unsigned long start_addr, + unsigned long end_addr) { struct vm_area_struct * vma = find_vma(mm,start_addr);
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