Messages in this thread Patch in this message | | | Subject | Re: [PATCH v4 1/2] clk: hisilicon: Use correct return value about hisi_reset_init() | From | Tiezhu Yang <> | Date | Fri, 29 May 2020 10:03:54 +0800 |
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On 05/29/2020 07:15 AM, Stephen Boyd wrote: > Quoting Tiezhu Yang (2020-05-27 19:27:42) >> On 05/28/2020 03:06 AM, Stephen Boyd wrote: >>> Quoting Tiezhu Yang (2020-05-27 07:39:21) >>>> The return value about hisi_reset_init() is not correct, fix it. >>>> >>>> Fixes: e9a2310fb689 ("reset: hisilicon: fix potential NULL pointer dereference") >>> hisi_reset_init() returns NULL on error in that commit. This patch >>> doesn't make sense. >> Hi Stephen, >> >> The initial aim of this patch is to use correct return value about >> hisi_reset_init(), maybe NULL is OK, but the return value in this >> patch is more accurate. > The implementation of hisi_reset_init() that I see is this: > > > struct hisi_reset_controller *rstc; > > rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL); > if (!rstc) > return NULL; > > rstc->membase = devm_platform_ioremap_resource(pdev, 0); > if (IS_ERR(rstc->membase)) > return NULL; > > spin_lock_init(&rstc->lock); > rstc->rcdev.owner = THIS_MODULE; > rstc->rcdev.ops = &hisi_reset_ops; > rstc->rcdev.of_node = pdev->dev.of_node; > rstc->rcdev.of_reset_n_cells = 2; > rstc->rcdev.of_xlate = hisi_reset_of_xlate; > reset_controller_register(&rstc->rcdev); > > return rstc; > > And that returns NULL on an error and a valid pointer on success. > Changing the code to check the return value of hisi_reset_init() for an > error pointer is simply wrong without updating hisi_reset_init() to > return an error pointer on error. Where is the patch that changes > hisi_reset_init() to return an error pointer?
Hi Stephen,
Do you mean the following changes?
diff --git a/drivers/clk/hisilicon/reset.c b/drivers/clk/hisilicon/reset.c index 93cee17..c733e2e 100644 --- a/drivers/clk/hisilicon/reset.c +++ b/drivers/clk/hisilicon/reset.c @@ -93,11 +93,11 @@ struct hisi_reset_controller *hisi_reset_init(struct platform_device *pdev) rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL); if (!rstc) - return NULL; + return ERR_PTR(-ENOMEM); rstc->membase = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(rstc->membase)) - return NULL; + return ERR_CAST(rstc->membase); spin_lock_init(&rstc->lock); rstc->rcdev.owner = THIS_MODULE;
devm_platform_ioremap_resource() devm_ioremap_resource() __devm_ioremap_resource()
By the way, we can see the comment of devm_ioremap_resource():
Usage example:
res = platform_get_resource(pdev, IORESOURCE_MEM, 0); base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(base)) return PTR_ERR(base);
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