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    SubjectRe: [PATCH 2/2] auxdisplay/ht16k33.c: Convert to use vm_map_pages_zero()
    On Fri, May 24, 2019 at 8:07 AM Souptick Joarder <jrdr.linux@gmail.com> wrote:
    >
    > > > Taking a quick look now, by the way, why does vm_map_pages_zero() (and
    > > > __vm_map_pages() etc.) get a pointer to an array instead of a pointer
    > > > to the first element?
    >
    > For this particular driver, one page is getting mapped into vma. But
    > there are other
    > places where a entire page array ( with more than one pages) mapped into
    > vma. That's the reason to pass pointer to an array and do rest of the operations
    > inside __vm_map_pages().

    Ah, "pointer to array of source kernel pages" made me think the actual
    `struct page`s were the ones consecutive in memory, not the pointers.
    Maybe "array of page pointers" is more clear.

    > > Also, in __vm_map_pages(), semantically w.r.t. to the comment,
    > > shouldn't the first check test for equality too? (i.e. for vm_pgoff ==
    > > num)? (even if such case fails in the second test anyway).
    >
    > Sorry, didn't get it. Do you mean there should be a separate check for
    > *vm_pgoff == num* ?

    No, that the first check should be widened. I will send a patch.

    Cheers,
    Miguel

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