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    Subject[PATCH v14 36/70] xtensa: remove vma linked list walks
    Date
    From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

    Use the VMA iterator instead. Since VMA can no longer be NULL in the
    loop, then deal with out-of-memory outside the loop. This means a
    slightly longer run time in the failure case (-ENOMEM) - it will run to
    the end of the VMAs before erroring instead of in the middle of the loop.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
    Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
    ---
    arch/xtensa/kernel/syscall.c | 18 ++++++++++++------
    1 file changed, 12 insertions(+), 6 deletions(-)

    diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
    index 201356faa7e6..b3c2450d6f23 100644
    --- a/arch/xtensa/kernel/syscall.c
    +++ b/arch/xtensa/kernel/syscall.c
    @@ -58,6 +58,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
    unsigned long len, unsigned long pgoff, unsigned long flags)
    {
    struct vm_area_struct *vmm;
    + struct vma_iterator vmi;

    if (flags & MAP_FIXED) {
    /* We do not accept a shared mapping if it would violate
    @@ -79,15 +80,20 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
    else
    addr = PAGE_ALIGN(addr);

    - for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
    - /* At this point: (!vmm || addr < vmm->vm_end). */
    - if (TASK_SIZE - len < addr)
    - return -ENOMEM;
    - if (!vmm || addr + len <= vm_start_gap(vmm))
    - return addr;
    + vma_iter_init(&vmi, current->mm, addr);
    + for_each_vma(vmi, vmm) {
    + /* At this point: (addr < vmm->vm_end). */
    + if (addr + len <= vm_start_gap(vmm))
    + break;
    +
    addr = vmm->vm_end;
    if (flags & MAP_SHARED)
    addr = COLOUR_ALIGN(addr, pgoff);
    }
    +
    + if (TASK_SIZE - len < addr)
    + return -ENOMEM;
    +
    + return addr;
    }
    #endif
    --
    2.35.1
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