From: Alan Cox Date: Wed, 26 Sep 2007 22:02:52 +0000 (+0100) Subject: pata_atiixp: Audit notes on locking X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=21d2c925d3da6aabf9a0b34e95787202379f682a;p=deliverable%2Flinux.git pata_atiixp: Audit notes on locking Signed-off-by: Alan Cox Signed-off-by: Jeff Garzik --- diff --git a/drivers/ata/pata_atiixp.c b/drivers/ata/pata_atiixp.c index 95ed3071a0a0..9623f5295530 100644 --- a/drivers/ata/pata_atiixp.c +++ b/drivers/ata/pata_atiixp.c @@ -173,6 +173,9 @@ static void atiixp_set_dmamode(struct ata_port *ap, struct ata_device *adev) * * When DMA begins we need to ensure that the UDMA control * register for the channel is correctly set. + * + * Note: The host lock held by the libata layer protects + * us from two channels both trying to set DMA bits at once */ static void atiixp_bmdma_start(struct ata_queued_cmd *qc) @@ -199,6 +202,9 @@ static void atiixp_bmdma_start(struct ata_queued_cmd *qc) * * DMA has completed. Clear the UDMA flag as the next operations will * be PIO ones not UDMA data transfer. + * + * Note: The host lock held by the libata layer protects + * us from two channels both trying to set DMA bits at once */ static void atiixp_bmdma_stop(struct ata_queued_cmd *qc)