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    SubjectRe: [PATCH 03/10] ide: destroy DMA mappings after ending DMA
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    On Fri, Feb 20, 2009 at 6:12 PM, Bartlomiej Zolnierkiewicz
    <bzolnier@gmail.com> wrote:
    > From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
    > Subject: [PATCH] ide: destroy DMA mappings after ending DMA
    >
    > Move ide_destroy_dmatable() call out from ->dma_end method to
    > {ide_pc,cdrom_newpc,ide_dma}_intr(), ide_dma_timeout_retry()
    > and sgiioc4_resetproc().
    ...
    > --- a/drivers/ide/ide-dma-sff.c
    > +++ b/drivers/ide/ide-dma-sff.c
    > @@ -310,8 +310,6 @@ int ide_dma_end(ide_drive_t *drive)
    >        /* clear INTR & ERROR bits */
    >        ide_dma_sff_write_status(hwif, dma_stat | ATA_DMA_ERR | ATA_DMA_INTR);
    >
    > -       /* purge DMA mappings */
    > -       ide_destroy_dmatable(drive);
    >        wmb();

    Bartlomiej,
    I think the wmb() could removed as well. The outb/writeb functions are
    required to be strongly ordered and I don't see anything else touching
    DMA-able memory here.

    BTW, care to remove "mask" usage from this function?
    It's really not needed (can be replaced with #define).

    I can create separate patches for both. Which git tree should I base
    them against?

    ...
    > --- a/drivers/ide/scc_pata.c
    > +++ b/drivers/ide/scc_pata.c
    > @@ -365,8 +365,6 @@ static int __scc_dma_end(ide_drive_t *dr
    >        dma_stat = scc_dma_sff_read_status(hwif);
    >        /* clear the INTR & ERROR bits */
    >        scc_ide_outb(dma_stat | 6, hwif->dma_base + 4);
    > -       /* purge DMA mappings */
    > -       ide_destroy_dmatable(drive);
    >        /* verify good DMA status */
    >        wmb();

    I think this wmb() can be removed too.

    ....
    > --- a/drivers/ide/tx4939ide.c
    > +++ b/drivers/ide/tx4939ide.c
    > @@ -335,11 +335,9 @@ static int tx4939ide_dma_end(ide_drive_t
    >        /* read and clear the INTR & ERROR bits */
    >        dma_stat = tx4939ide_clear_dma_status(base);
    >
    > -       /* purge DMA mappings */
    > -       ide_destroy_dmatable(drive);
    > -       /* verify good DMA status */
    >        wmb();

    and this one as well.

    hth,
    grant
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