If the atomic DMA coherent pool is too small, disable use of hardware descriptor lists instead of crashing the system:
ERROR: 256 KiB atomic DMA coherent pool is too small! Please increase it with coherent_pool= kernel parameter! Unable to handle kernel NULL pointer dereference at virtual address 00000004 Internal error: Oops: a07 [#1] PREEMPT SMP ARM PC is at rcar_dmac_chan_reinit+0x3c/0x160 LR is at _raw_spin_lock_irqsave+0x18/0x5c [<802132c0>] (rcar_dmac_chan_reinit) from [<80214818>] (rcar_dmac_isr_error+0x84/0xa0) [<80214818>] (rcar_dmac_isr_error) from [<80060484>] (handle_irq_event_percpu+0x50/0x150) [<80060484>] (handle_irq_event_percpu) from [<800605c0>] (handle_irq_event+0x3c/0x5c) [<800605c0>] (handle_irq_event) from [<8006350c>] (handle_fasteoi_irq+0xb8/0x198) [<8006350c>] (handle_fasteoi_irq) from [<8005fdb0>] (generic_handle_irq+0x20/0x30) [<8005fdb0>] (generic_handle_irq) from [<8000fcd0>] (handle_IRQ+0x50/0xc4) [<8000fcd0>] (handle_IRQ) from [<800092cc>] (gic_handle_irq+0x28/0x5c) [<800092cc>] (gic_handle_irq) from [<80012700>] (__irq_svc+0x40/0x70) Kernel panic - not syncing: Fatal exception in interrupt Signed-off-by: Jürg Billeter <[email protected]> --- drivers/dma/sh/rcar-dmac.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index f8f70eb..f18b1b6 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -679,8 +679,8 @@ static void rcar_dmac_realloc_hwdesc(struct rcar_dmac_chan *chan, desc->hwdescs.size = size; } -static void rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan, - struct rcar_dmac_desc *desc) +static int rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan, + struct rcar_dmac_desc *desc) { struct rcar_dmac_xfer_chunk *chunk; struct rcar_dmac_hw_desc *hwdesc; @@ -689,7 +689,7 @@ static void rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan, hwdesc = desc->hwdescs.mem; if (!hwdesc) - return; + return -ENOMEM; list_for_each_entry(chunk, &desc->chunks, node) { hwdesc->sar = chunk->src_addr; @@ -697,6 +697,8 @@ static void rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan, hwdesc->tcr = chunk->size >> desc->xfer_shift; hwdesc++; } + + return 0; } /* ----------------------------------------------------------------------------- @@ -933,8 +935,10 @@ rcar_dmac_chan_prep_sg(struct rcar_dmac_chan *chan, struct scatterlist *sgl, * additional complexity remains to be investigated. */ desc->hwdescs.use = !highmem && nchunks > 1; - if (desc->hwdescs.use) - rcar_dmac_fill_hwdesc(chan, desc); + if (desc->hwdescs.use) { + if (rcar_dmac_fill_hwdesc(chan, desc) < 0) + desc->hwdescs.use = false; + } return &desc->async_tx; } -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
