dmaengine: sh: rz-dmac: Avoid format-overflow warning

The max channel count for RZ DMAC is 16, hence use u8 instead of unsigned
int and make the pdev_irqname string long enough to avoid the warning.

This fixes the below issue:
drivers/dma/sh/rz-dmac.c: In function ‘rz_dmac_probe’:
drivers/dma/sh/rz-dmac.c:770:34: warning: ‘%u’ directive writing between 1 and 10 bytes into a region of size 3 [-Wformat-overflow=]
  770 |         sprintf(pdev_irqname, "ch%u", index);
      |                                  ^~
In function ‘rz_dmac_chan_probe’,
    inlined from ‘rz_dmac_probe’ at drivers/dma/sh/rz-dmac.c:910:9:
drivers/dma/sh/rz-dmac.c:770:31: note: directive argument in the range [0, 4294967294]
  770 |         sprintf(pdev_irqname, "ch%u", index);
      |                               ^~~~~~
drivers/dma/sh/rz-dmac.c:770:9: note: ‘sprintf’ output between 4 and 13 bytes into a destination of size 5
  770 |         sprintf(pdev_irqname, "ch%u", index);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

While at it use scnprintf() instead of sprintf() to make the code
more robust.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20240110222717.193719-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index fea5bda34bc20f679b987e0a2d4ffde4f28e1f7c..1f1e86ba5c66aa8c33556eabb34a94ba431e4cc8 100644 (file)
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -755,11 +755,11 @@ static struct dma_chan *rz_dmac_of_xlate(struct of_phandle_args *dma_spec,
 
 static int rz_dmac_chan_probe(struct rz_dmac *dmac,
                              struct rz_dmac_chan *channel,
-                             unsigned int index)
+                             u8 index)
 {
        struct platform_device *pdev = to_platform_device(dmac->dev);
        struct rz_lmdesc *lmdesc;
-       char pdev_irqname[5];
+       char pdev_irqname[6];
        char *irqname;
        int ret;
 
@@ -767,7 +767,7 @@ static int rz_dmac_chan_probe(struct rz_dmac *dmac,
        channel->mid_rid = -EINVAL;
 
        /* Request the channel interrupt. */
-       sprintf(pdev_irqname, "ch%u", index);
+       scnprintf(pdev_irqname, sizeof(pdev_irqname), "ch%u", index);
        channel->irq = platform_get_irq_byname(pdev, pdev_irqname);
        if (channel->irq < 0)
                return channel->irq;
@@ -845,9 +845,9 @@ static int rz_dmac_probe(struct platform_device *pdev)
        struct dma_device *engine;
        struct rz_dmac *dmac;
        int channel_num;
-       unsigned int i;
        int ret;
        int irq;
+       u8 i;
 
        dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
        if (!dmac)