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] [mhocko@xxxxxxxxxx: fix mremap.c and uprobes.c sites also] Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@xxxxxxxxx Signed-off-by: Gaowei Pu <pugaowei@xxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/events/uprobes.c | 2 +- mm/mmap.c | 9 +++++---- mm/mremap.c | 4 ++-- 3 files changed, 8 insertions(+), 7 deletions(-) --- a/kernel/events/uprobes.c~mm-mmapc-use-is_err_value-to-check-return-value-of-get_unmapped_area +++ a/kernel/events/uprobes.c @@ -1457,7 +1457,7 @@ static int xol_add_vma(struct mm_struct /* 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; } --- 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) { @@ -2981,15 +2981,16 @@ 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) --- a/mm/mremap.c~mm-mmapc-use-is_err_value-to-check-return-value-of-get_unmapped_area +++ a/mm/mremap.c @@ -558,7 +558,7 @@ static unsigned long mremap_to(unsigned 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, a 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; } _
