Re: [PATCH] ata: ahci: preserve preset port masks

[Niklas Cassel <cassel@kernel.org>]

On Thu, Oct 15, 2026 at 11:06:55AM +0800, zhoumin wrote:
> ahci_get_port_mask() returns zero for absent or unmatched parameters,
> overwriting the mask set by the Marvell PATA quirk.
> 
> Update the mask in place only when parsing a global value or a matching
> device entry. Preserve existing numeric parsing and override behavior.
> 
> Fixes: 70c1595c181c ("ata: ahci: Allow ignoring the external/hotplug capability of ports")
> Signed-off-by: zhoumin <teczm@foxmail.com>
> ---
>  drivers/ata/ahci.c | 21 +++++++++------------
>  1 file changed, 9 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index 9b8c0935001c..324e4918a055 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -1654,22 +1654,21 @@ static u32 ahci_port_mask(struct device *dev, char *mask_s)
>  	return mask;
>  }
>  
> -static u32 ahci_get_port_mask(struct device *dev, char *mask_p)
> +static void ahci_get_port_mask(struct device *dev, char *mask_p, u32 *mask)
>  {
>  	char *param, *end, *str, *mask_s;
>  	char *name;
> -	u32 mask = 0;
>  
>  	if (!mask_p || !strlen(mask_p))
> -		return 0;
> +		return;
>  
>  	str = kstrdup(mask_p, GFP_KERNEL);
>  	if (!str)
> -		return 0;
> +		return;
>  
>  	/* Handle single mask case */
>  	if (!strchr(str, '=')) {
> -		mask = ahci_port_mask(dev, str);
> +		*mask = ahci_port_mask(dev, str);
>  		goto free;
>  	}
>  
> @@ -1704,13 +1703,11 @@ static u32 ahci_get_port_mask(struct device *dev, char *mask_p)
>  			param++;
>  		}
>  
> -		mask = ahci_port_mask(dev, mask_s);
> +		*mask = ahci_port_mask(dev, mask_s);
>  	}
>  
>  free:
>  	kfree(str);
> -
> -	return mask;

Invalid values still wipe out the Marvell mask.
ahci_port_mask()  returns 0 when parsing fails, and the patch writes that
0 into the mask.

Before 70c1595c181c a bad value left the mask alone.

I suggest the following change on top of your patch:

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 324e4918a055..fdce365969b4 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1642,16 +1642,10 @@ MODULE_PARM_DESC(mask_port_ext,
 		 "where <pci_dev> is the PCI ID of an AHCI controller in the "
 		 "form \"domain:bus:dev.func\"");
 
-static u32 ahci_port_mask(struct device *dev, char *mask_s)
+static void ahci_port_mask(struct device *dev, char *mask_s, u32 *mask)
 {
-	unsigned int mask;
-
-	if (kstrtouint(mask_s, 0, &mask)) {
+	if (kstrtou32(mask_s, 0, mask))
 		dev_err(dev, "Invalid port map mask\n");
-		return 0;
-	}
-
-	return mask;
 }
 
 static void ahci_get_port_mask(struct device *dev, char *mask_p, u32 *mask)
@@ -1668,7 +1662,7 @@ static void ahci_get_port_mask(struct device *dev, char *mask_p, u32 *mask)
 
 	/* Handle single mask case */
 	if (!strchr(str, '=')) {
-		*mask = ahci_port_mask(dev, str);
+		ahci_port_mask(dev, str, mask);
 		goto free;
 	}
 
@@ -1703,7 +1697,7 @@ static void ahci_get_port_mask(struct device *dev, char *mask_p, u32 *mask)
 			param++;
 		}
 
-		*mask = ahci_port_mask(dev, mask_s);
+		ahci_port_mask(dev, mask_s, mask);
 	}
 
 free:







 This relies on  kstrtou32()  writing its result only on success.
 That is documented ("@res: Where to write the result of the conversion
 on success") and matches the code in  lib/kstrtox.c.
 So a bad value now just logs the error and leaves  the Marvell mask alone.