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    SubjectRe: [ 04/21] target/pscsi: Fix page increment
    On Sat, Mar 16, 2013 at 02:10:22AM +0000, Ben Hutchings wrote:
    > On Tue, 2013-03-12 at 15:44 -0700, Greg Kroah-Hartman wrote:
    > > 3.0-stable review patch. If anyone has any objections, please let me know.
    > >
    > > ------------------
    > >
    > > From: Asias He <asias@redhat.com>
    > >
    > > commit 472b72f2db7831d7dbe22ffdff4adee3bd49b05d upstream.
    > >
    > > The page++ is wrong. It makes bio_add_pc_page() pointing to a wrong page
    > > address if the 'while (len > 0 && data_len > 0) { ... }' loop is
    > > executed more than one once.
    > >
    > > Signed-off-by: Asias He <asias@redhat.com>
    > > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
    > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    > >
    > > ---
    > > drivers/target/target_core_pscsi.c | 1 -
    > > 1 file changed, 1 deletion(-)
    > >
    > > --- a/drivers/target/target_core_pscsi.c
    > > +++ b/drivers/target/target_core_pscsi.c
    > > @@ -1210,7 +1210,6 @@ static int __pscsi_map_task_SG(
    > > bio = NULL;
    > > }
    > >
    > > - page++;
    > > len -= bytes;
    > > data_len -= bytes;
    > > off = 0;
    >
    > So in case a fragment crosses a page boundary, we wrap around to the
    > beginning of the same page? That doesn't look right.

    If the fragment crosses a page boundary, what is the correct page
    for it?

    Nicholas, can we assume sg->length + sg->offset should be less than PAGE_SIZE here?

    > Ben.
    >
    > --
    > Ben Hutchings
    > It is easier to change the specification to fit the program than vice versa.

    --
    Asias

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