Date:   Mon, 13 Mar 2023 14:14:47 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, rafael@kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Alex Shi <alexs@kernel.org>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Alexandre Bounine <alex.bou9@gmail.com>,
        Alison Schofield <alison.schofield@intel.com>,
        Ben Widawsky <bwidawsk@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dexuan Cui <decui@microsoft.com>,
        Eric Dumazet <edumazet@google.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Hannes Reinecke <hare@suse.de>,
        Harald Freudenberger <freude@linux.ibm.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Hu Haowen <src.res@email.cn>,
        Ilya Dryomov <idryomov@gmail.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Iwona Winiarska <iwona.winiarska@intel.com>,
        Jakub Kicinski <kuba@kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Jonathan Corbet <corbet@lwn.net>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Matt Porter <mporter@kernel.crashing.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paolo Abeni <pabeni@redhat.com>,
        Stuart Yoder <stuyoder@gmail.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Wei Liu <wei.liu@kernel.org>,
        Yanteng Si <siyanteng@loongson.cn>
Subject: Re: [PATCH 23/36] driver core: bus: mark the struct bus_type for
 sysfs callbacks as constant
Message-ID: <20230313191447.GA1528028@bhelgaas>
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On Mon, Mar 13, 2023 at 07:29:05PM +0100, Greg Kroah-Hartman wrote:
> struct bus_type should never be modified in a sysfs callback as there is
> nothing in the structure to modify, and frankly, the structure is almost
> never used in a sysfs callback, so mark it as constant to allow struct
> bus_type to be moved to read-only memory.
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: Alex Shi <alexs@kernel.org>
> Cc: Alexander Gordeev <agordeev@linux.ibm.com>
> Cc: Alexandre Bounine <alex.bou9@gmail.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Cc: Ben Widawsky <bwidawsk@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Dexuan Cui <decui@microsoft.com>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Harald Freudenberger <freude@linux.ibm.com>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Hu Haowen <src.res@email.cn>
> Cc: Ilya Dryomov <idryomov@gmail.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: Iwona Winiarska <iwona.winiarska@intel.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Cc: Matt Porter <mporter@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Stuart Yoder <stuyoder@gmail.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Yanteng Si <siyanteng@loongson.cn>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>	# pci

> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index dd0d9d9bc509..ab32a91f287b 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -428,7 +428,7 @@ static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr,
>  }
>  static DEVICE_ATTR_RW(msi_bus);
>  
> -static ssize_t rescan_store(struct bus_type *bus, const char *buf, size_t count)
> +static ssize_t rescan_store(const struct bus_type *bus, const char *buf, size_t count)
>  {
>  	unsigned long val;
>  	struct pci_bus *b = NULL;
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7a67611dc5f4..45c3bb039f21 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6679,7 +6679,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
>  	}
>  }
>  
> -static ssize_t resource_alignment_show(struct bus_type *bus, char *buf)
> +static ssize_t resource_alignment_show(const struct bus_type *bus, char *buf)
>  {
>  	size_t count = 0;
>  
> @@ -6691,7 +6691,7 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf)
>  	return count;
>  }
>  
> -static ssize_t resource_alignment_store(struct bus_type *bus,
> +static ssize_t resource_alignment_store(const struct bus_type *bus,
>  					const char *buf, size_t count)
>  {
>  	char *param, *old, *end;