On Tue 15-10-19 13:48:19, Andrew Morton wrote: > From: Gaowei Pu <pugaowei@xxxxxxxxx> > Subject: mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area > > get_unmapped_area() returns an address or -errno on failure. Historically > we have checked for the failure by offset_in_page() which is correct but > quite hard to read. Newer code started using IS_ERR_VALUE which is much > easier to read. Convert remaining users of offset_in_page as well. > > [mhocko@xxxxxxxx: rewrite changelog] > Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@xxxxxxxxx > Signed-off-by: Gaowei Pu <pugaowei@xxxxxxxxx> > Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> There are few more to convert diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 94d38a39d72e..9c197a26c0f4 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1448,7 +1448,7 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) /* Try to map as high as possible, this is only a hint. */ area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); - if (area->vaddr & ~PAGE_MASK) { + if (IS_ERR_VALUE(area->vaddr)) { ret = area->vaddr; goto fail; } diff --git a/mm/mremap.c b/mm/mremap.c index 1fc8a29fbe3f..122938dcec15 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -558,7 +558,7 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT), map_flags); - if (offset_in_page(ret)) + if (IS_ERR_VALUE(ret)) goto out1; ret = move_vma(vma, addr, old_len, new_len, new_addr, locked, uf, @@ -706,7 +706,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT), map_flags); - if (offset_in_page(new_addr)) { + if (IS_ERR_VALUE(new_addr)) { ret = new_addr; goto out; } and also few more to consider. e.g. move_vma return value checks. I haven't checked other offset_in_page users. > --- > > mm/mmap.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > --- a/mm/mmap.c~mm-mmapc-use-is_err_value-to-check-return-value-of-get_unmapped_area > +++ a/mm/mmap.c > @@ -1417,7 +1417,7 @@ unsigned long do_mmap(struct file *file, > * that it represents a valid section of the address space. > */ > addr = get_unmapped_area(file, addr, len, pgoff, flags); > - if (offset_in_page(addr)) > + if (IS_ERR_VALUE(addr)) > return addr; > > if (flags & MAP_FIXED_NOREPLACE) { > @@ -2996,15 +2996,16 @@ static int do_brk_flags(unsigned long ad > struct rb_node **rb_link, *rb_parent; > pgoff_t pgoff = addr >> PAGE_SHIFT; > int error; > + unsigned long mapped_addr; > > /* Until we need other flags, refuse anything except VM_EXEC. */ > if ((flags & (~VM_EXEC)) != 0) > return -EINVAL; > flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; > > - error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); > - if (offset_in_page(error)) > - return error; > + mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); > + if (IS_ERR_VALUE(mapped_addr)) > + return mapped_addr; > > error = mlock_future_check(mm, mm->def_flags, len); > if (error) > _ > > Patches currently in -mm which might be from pugaowei@xxxxxxxxx are > > mm-mmapc-use-is_err_value-to-check-return-value-of-get_unmapped_area.patch -- Michal Hocko SUSE Labs
