ARM: S3C64XX: DMA: Protect buffer pointers while manipulation

Ensure the DMA buffer points are not updated from
another source during the process of enquing a buffer.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
[ben-linux@fluff.org: Updated patch comment]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

diff --git a/arch/arm/plat-s3c64xx/dma.c b/arch/arm/plat-s3c64xx/dma.c
index 266a107..6fa706f 100644 (file)
--- a/arch/arm/plat-s3c64xx/dma.c
+++ b/arch/arm/plat-s3c64xx/dma.c
@@ -339,6 +339,7 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
        struct s3c64xx_dma_buff *next;
        struct s3c64xx_dma_buff *buff;
        struct pl080s_lli *lli;
+       unsigned long flags;
        int ret;
 
        WARN_ON(!chan);
@@ -366,6 +367,8 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
 
        s3c64xx_dma_fill_lli(chan, lli, data, size);
 
+       local_irq_save(flags);
+
        if ((next = chan->next) != NULL) {
                struct s3c64xx_dma_buff *end = chan->end;
                struct pl080s_lli *endlli = end->lli;
@@ -397,6 +400,8 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
                s3c64xx_lli_to_regs(chan, lli);
        }
 
+       local_irq_restore(flags);
+
        show_lli(lli);
 
        dbg_showchan(chan);