It was <2020-08-19 śro 14:48>, when Krzysztof Kozlowski wrote: > On Wed, Aug 19, 2020 at 02:32:06PM +0200, Łukasz Stelmach wrote: >> Signed-off-by: Łukasz Stelmach <[email protected]> >> --- >> drivers/spi/spi-s3c64xx.c | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) > > Oh, come on, stop fixing the same local issue without fixing bigger > picture... or at least documenting why bigger picture does not have to be > fixed and simple 'return' is enough. > > That's the third, same fix for the same problem. > > https://lore.kernel.org/lkml/[email protected]/ > https://lore.kernel.org/lkml/20170207204520.h2eo3yn5kge56lk7@kozik-lap/
No wonder. There is a possible NULL dereference below. Now at least we
know something about conditions that led to this.
Should I drop the entire patch, or just the dmaengine_prep_slave_sg() part?
>> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
>> index 505789f91fdf..27d77600a820 100644
>> --- a/drivers/spi/spi-s3c64xx.c
>> +++ b/drivers/spi/spi-s3c64xx.c
>> @@ -273,6 +273,7 @@ static void prepare_dma(struct s3c64xx_spi_dma_data *dma,
>> struct s3c64xx_spi_driver_data *sdd;
>> struct dma_slave_config config;
>> struct dma_async_tx_descriptor *desc;
>> + int ret;
>>
>> memset(&config, 0, sizeof(config));
>>
>> @@ -296,11 +297,22 @@ static void prepare_dma(struct s3c64xx_spi_dma_data
>> *dma,
>>
>> desc = dmaengine_prep_slave_sg(dma->ch, sgt->sgl, sgt->nents,
>> dma->direction, DMA_PREP_INTERRUPT);
>> + if (!desc) {
>> + dev_err(&sdd->pdev->dev, "unable to prepare %s scatterlist",
>> + dma->direction == DMA_DEV_TO_MEM ? "rx" : "tx");
>> + return;
>> + }
>>
>> desc->callback = s3c64xx_spi_dmacb;
>> desc->callback_param = dma;
>>
>> dma->cookie = dmaengine_submit(desc);
>> + ret = dma_submit_error(dma->cookie);
>> + if (ret) {
>> + dev_err(&sdd->pdev->dev, "dmaengine_submit() failed %d", ret);
>> + return;
>> + }
>> +
>> dma_async_issue_pending(dma->ch);
>> }
>>
>> --
>> 2.26.2
>>
>
>
--
Łukasz Stelmach
Samsung R&D Institute Poland
Samsung Electronics
signature.asc
Description: PGP signature
