vma_shrink() is only used by relocate_vma_down() to shrink the tail of a VMA. Therefore neither the start nor the pgoff parameters make any sense.
It seemed we were passing the pgoff parameter solely to satisfy vma_set_range()'s requirement for pgoff being specified. Since vma_set_range() is now isolated to vma.c, we can simply introduce __vma_set_range() which sets only vma->vm_[start, end], and invoke this instead, removing start and pgoff from vma_shrink() altogether. No functional change intended. Reviewed-by: Pedro Falcato <[email protected]> Signed-off-by: Lorenzo Stoakes <[email protected]> --- mm/vma.c | 31 +++++++++++++++++-------------- mm/vma.h | 3 +-- mm/vma_exec.c | 2 +- tools/testing/vma/tests/merge.c | 2 +- 4 files changed, 20 insertions(+), 18 deletions(-) diff --git a/mm/vma.c b/mm/vma.c index cc0e449ad0be..a474920a25b3 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -70,11 +70,17 @@ struct mmap_state { .state = VMA_MERGE_START, \ } -static void vma_set_range(struct vm_area_struct *vma, unsigned long start, - unsigned long end, pgoff_t pgoff) +static void __vma_set_range(struct vm_area_struct *vma, unsigned long start, + unsigned long end) { vma->vm_start = start; vma->vm_end = end; +} + +static void vma_set_range(struct vm_area_struct *vma, unsigned long start, + unsigned long end, pgoff_t pgoff) +{ + __vma_set_range(vma, start, end); vma->vm_pgoff = pgoff; } @@ -1279,27 +1285,24 @@ int vma_expand(struct vma_merge_struct *vmg) return -ENOMEM; } -/* - * vma_shrink() - Reduce an existing VMAs memory area +/** + * vma_shrink() - Shrink the end of a VMA * @vmi: The vma iterator * @vma: The VMA to modify - * @start: The new start * @end: The new end * + * Note that the caller may only shrink the end of the VMA. + * * Returns: 0 on success, -ENOMEM otherwise */ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long start, unsigned long end, pgoff_t pgoff) + unsigned long end) { struct vma_prepare vp; - WARN_ON((vma->vm_start != start) && (vma->vm_end != end)); - - if (vma->vm_start < start) - vma_iter_config(vmi, vma->vm_start, start); - else - vma_iter_config(vmi, end, vma->vm_end); + VM_WARN_ON_ONCE(end > vma->vm_end); + vma_iter_config(vmi, end, vma->vm_end); if (vma_iter_prealloc(vmi, NULL)) return -ENOMEM; @@ -1307,10 +1310,10 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, init_vma_prep(&vp, vma); vma_prepare(&vp); - vma_adjust_trans_huge(vma, start, end, NULL); + vma_adjust_trans_huge(vma, vma->vm_start, end, NULL); vma_iter_clear(vmi); - vma_set_range(vma, start, end, pgoff); + __vma_set_range(vma, vma->vm_start, end); vma_complete(&vp, vmi, vma->vm_mm); validate_mm(vma->vm_mm); return 0; diff --git a/mm/vma.h b/mm/vma.h index 14f026bf3be4..40effaa3ebe4 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -297,8 +297,7 @@ void validate_mm(struct mm_struct *mm); __must_check int vma_expand(struct vma_merge_struct *vmg); __must_check int vma_shrink(struct vma_iterator *vmi, - struct vm_area_struct *vma, - unsigned long start, unsigned long end, pgoff_t pgoff); + struct vm_area_struct *vma, unsigned long end); static inline int vma_iter_store_gfp(struct vma_iterator *vmi, struct vm_area_struct *vma, gfp_t gfp) diff --git a/mm/vma_exec.c b/mm/vma_exec.c index e3644a3042e2..13a05e041195 100644 --- a/mm/vma_exec.c +++ b/mm/vma_exec.c @@ -89,7 +89,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift) vma_prev(&vmi); /* Shrink the vma to just the new range */ - return vma_shrink(&vmi, vma, new_start, new_end, vma_start_pgoff(vma)); + return vma_shrink(&vmi, vma, new_end); } /* diff --git a/tools/testing/vma/tests/merge.c b/tools/testing/vma/tests/merge.c index f8666a755749..e357accc8499 100644 --- a/tools/testing/vma/tests/merge.c +++ b/tools/testing/vma/tests/merge.c @@ -227,7 +227,7 @@ static bool test_simple_shrink(void) ASSERT_FALSE(attach_vma(&mm, vma)); - ASSERT_FALSE(vma_shrink(&vmi, vma, 0, 0x1000, 0)); + ASSERT_FALSE(vma_shrink(&vmi, vma, 0x1000)); ASSERT_EQ(vma->vm_start, 0); ASSERT_EQ(vma->vm_end, 0x1000); -- 2.55.0
