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Subject: Re: [PATCH v2 2/3] scsi: ufs: Modulize ufs-bsg
To:     Can Guo <cang@codeaurora.org>, <asutoshd@codeaurora.org>,
        <nguyenb@codeaurora.org>, <rnayak@codeaurora.org>,
        <linux-scsi@vger.kernel.org>, <kernel-team@android.com>,
        <saravanak@google.com>, <salyzyn@google.com>
CC:     Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        Pedro Sousa <pedrom.sousa@synopsys.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Evan Green <evgreen@chromium.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        open list <linux-kernel@vger.kernel.org>
References: <1576054123-16417-1-git-send-email-cang@codeaurora.org>
 <0101016ef425ed74-071c2ec2-5aeb-44fa-8889-d9ec60192d44-000000@us-west-2.amazonses.com>
From:   Vignesh Raghavendra <vigneshr@ti.com>
Message-ID: <c6a7f35f-289d-ff92-f8b1-e3e0731b30ab@ti.com>
Date:   Thu, 12 Dec 2019 11:10:15 +0530
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Hi,

On 11/12/19 2:19 pm, Can Guo wrote:
> In order to improve the flexibility of ufs-bsg, modulizing it is a good
> choice. This change introduces tristate to ufs-bsg to allow users compile
> it as an external module.
> 
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
[...]
> -int ufs_bsg_probe(struct ufs_hba *hba)
> +static int ufs_bsg_probe(struct ufs_hba *hba)
>  {
> -	struct device *bsg_dev = &hba->bsg_dev;
> +	struct device *bsg_dev;
>  	struct Scsi_Host *shost = hba->host;
>  	struct device *parent = &shost->shost_gendev;
>  	struct request_queue *q;
>  	int ret;
>  
> +	bsg_dev = kzalloc(sizeof(*bsg_dev), GFP_KERNEL);
> +	if (!bsg_dev)
> +		return -ENOMEM;
> +
> +	hba->bsg_dev = bsg_dev;
>  	device_initialize(bsg_dev);
>  
>  	bsg_dev->parent = get_device(parent);
> @@ -217,6 +225,41 @@ int ufs_bsg_probe(struct ufs_hba *hba)
>  
>  out:
>  	dev_err(bsg_dev, "fail to initialize a bsg dev %d\n", shost->host_no);
> +	hba->bsg_dev = NULL;

Don't we need to free the associated memory before assigning to NULL?
Alternatively can allocation be made with devm_ APIs instead?

>  	put_device(bsg_dev);
>  	return ret;
>  }
> +
> +static int __init ufs_bsg_init(void)
> +{
> +	struct list_head *hba_list = NULL;
> +	struct ufs_hba *hba;
> +	int ret = 0;
> +
> +	ufshcd_get_hba_list_lock(&hba_list);
> +	list_for_each_entry(hba, hba_list, list) {
> +		ret = ufs_bsg_probe(hba);
> +		if (ret)
> +			break;
> +	}

So IIUC, if ufs_bsg_probe() fails for one of the hba instances in the
list, then we fail to create bsg device for all remaining instances that
follow, which seems too harsh.

Regards
Vignesh