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    SubjectRe: [Fdutils] DMA cache consistency bug introduced in 2.6.28
    Linus Torvalds wrote:

    > diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
    > index 3266b4f..9c9148c 100644
    > --- a/drivers/block/floppy.c
    > +++ b/drivers/block/floppy.c
    > @@ -2237,13 +2237,10 @@ static void setup_format_params(int track)
    > for (count = 1; count <= F_SECT_PER_TRACK; ++count) {
    > here[n].sect = count;
    > n = (n + il) % F_SECT_PER_TRACK;
    > - if (here[n].sect) { /* sector busy, find next free sector */
    > + while (here[n].sect) { /* sector busy, find next free sector */
    > ++n;
    > - if (n >= F_SECT_PER_TRACK) {
    > + if (n >= F_SECT_PER_TRACK)
    > n -= F_SECT_PER_TRACK;
    > - while (here[n].sect)
    > - ++n;
    > - }
    > }
    > }
    > if (_floppy->stretch & FD_SECTBASEMASK) {

    The original code does indeed look a little bit strange... and might
    break if there is a long run of "busy" sectors near the end of the
    physical track. Or maybe there is a mathematical reason why this
    situation cannot occur. I'll have to think about it a little bit more to
    come up with a test case that will break either the new or old code.

    But in any case, if a bug would occur due to this code, it would only
    depend on the format's parameters, and not on the hardwarde.

    Regards,

    Alain


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