Hi Krzysztof, On 19 February 2016 at 11:36, Krzysztof Kozlowski <k.kozlow...@samsung.com> wrote: > 2016-02-19 2:21 GMT+09:00 Anand Moon <linux.am...@gmail.com>: >> From: Anand Moon <linux.am...@gmail.com> >> >> pl330_tasklet tasklet uses the same spinlock pch->lock for safe IRQ locking. >> It's safe to initialize pl330_tasklet tasklet after release of the locking. > > This is tasklet init, not tasklet execution (which you are referring > to in first sentence). I don't get how usage of spinlock during > execution guarantees the safeness during init... Please describe why > this is safe. > > Best regards, > Krzysztof >
http://lxr.free-electrons.com/source/drivers/dma/pl330.c#L1972 pl330_tasklet function which is initiated by tasklet_init is trying to lock using same spin_unlock_irqsave/restore pch->lock. So better release the pch->lock and then initialize the tasklet_init. Best Regards, -Anand Moon >> >> Signed-off-by: Anand Moon <linux.am...@gmail.com> >> --- >> drivers/dma/pl330.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c >> index 17ee758..df2cab1 100644 >> --- a/drivers/dma/pl330.c >> +++ b/drivers/dma/pl330.c >> @@ -2091,10 +2091,10 @@ static int pl330_alloc_chan_resources(struct >> dma_chan *chan) >> return -ENOMEM; >> } >> >> - tasklet_init(&pch->task, pl330_tasklet, (unsigned long) pch); >> - >> spin_unlock_irqrestore(&pch->lock, flags); >> >> + tasklet_init(&pch->task, pl330_tasklet, (unsigned long) pch); >> + >> return 1; >> } >> >> -- >> 1.9.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe dmaengine" in >> the body of a message to majord...@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html
