Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | Re: [PATCH] serial: sirf: Simplify a test | Date | Mon, 07 Nov 2016 14:50:27 +0100 |
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On Tuesday, November 1, 2016 8:03:33 AM CET Christophe JAILLET wrote: > 'dmaengine_prep_dma_cyclic()' does not return an error pointer, so the test > can be simplified to be more consistent. > > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
The change looks correct in principle. It would be good to automate looking for other instances of this bug. How did you find it? Do you have e.g. a coccinelle script or did you just stumble over the issue by accident?
There is one problem with your patch:
> drivers/tty/serial/sirfsoc_uart.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c > index b186c9c4f850..666ca3156961 100644 > --- a/drivers/tty/serial/sirfsoc_uart.c > +++ b/drivers/tty/serial/sirfsoc_uart.c > @@ -609,7 +609,7 @@ static void sirfsoc_uart_start_next_rx_dma(struct uart_port *port) > sirfport->rx_dma_items.dma_addr, SIRFSOC_RX_DMA_BUF_SIZE, > SIRFSOC_RX_DMA_BUF_SIZE / 2, > DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); > - if (IS_ERR_OR_NULL(sirfport->rx_dma_items.desc)) { > + if (!sirfport->rx_dma_items.desc) { > dev_err(port->dev, "DMA slave single fail\n"); > return; > }
The serial driver is for the sirf platform, which uses the sirf-dma dmaengine driver, and that particular driver has an incorrect dma_prep_cyclic implementation, so I think we also need this fix:
diff --git a/drivers/dma/sirf-dma.c b/drivers/dma/sirf-dma.c index 8f62edad51be..220c611c89ae 100644 --- a/drivers/dma/sirf-dma.c +++ b/drivers/dma/sirf-dma.c @@ -775,7 +775,7 @@ sirfsoc_dma_prep_cyclic(struct dma_chan *chan, dma_addr_t addr, * BUFB */ if (buf_len != 2 * period_len) - return ERR_PTR(-EINVAL); + return NULL; /* Get free descriptor */ spin_lock_irqsave(&schan->lock, iflags);
Arnd
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