linux-kernel - Re: [PATCH v2 1/2] scsi: hisi_sas: Remove unnecessary devm

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Date:   Tue, 12 Jan 2021 09:03:17 +0000
From:   John Garry <john.garry@...wei.com>
To:     Bean Huo <huobean@...il.com>, <alim.akhtar@...sung.com>,
        <avri.altman@....com>, <jejb@...ux.ibm.com>,
        <martin.petersen@...cle.com>, <ebiggers@...gle.com>,
        <satyat@...gle.com>, <shipujin.t@...il.com>
CC:     <linux-scsi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Bean Huo <beanhuo@...ron.com>
Subject: Re: [PATCH v2 1/2] scsi: hisi_sas: Remove unnecessary devm_kfree

On 11/01/2021 23:10, Bean Huo wrote:
> From: Bean Huo <beanhuo@...ron.com>
> 
> The memory allocated with devm_kzalloc() is freed automatically
> no need to explicitly call devm_kfree.
> 

This change is not right - we use devm_kfree() to manually release the 
devm-allocated debugfs memories upon memory allocation failure for 
driver debugfs feature during probe. The reason is that we allow the 
driver probe can still continue (for this failure).

Thanks,
John

> Signed-off-by: Bean Huo <beanhuo@...ron.com>
> ---
>   drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 28 +-------------------------
>   1 file changed, 1 insertion(+), 27 deletions(-)
> 
> diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
> index 91a7286e8102..5600411a0820 100644
> --- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
> +++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
> @@ -4172,30 +4172,6 @@ static void debugfs_work_handler_v3_hw(struct work_struct *work)
>   	hisi_hba->debugfs_dump_index++;
>   }
>   
> -static void debugfs_release_v3_hw(struct hisi_hba *hisi_hba, int dump_index)
> -{
> -	struct device *dev = hisi_hba->dev;
> -	int i;
> -
> -	devm_kfree(dev, hisi_hba->debugfs_iost_cache[dump_index].cache);
> -	devm_kfree(dev, hisi_hba->debugfs_itct_cache[dump_index].cache);
> -	devm_kfree(dev, hisi_hba->debugfs_iost[dump_index].iost);
> -	devm_kfree(dev, hisi_hba->debugfs_itct[dump_index].itct);
> -
> -	for (i = 0; i < hisi_hba->queue_count; i++)
> -		devm_kfree(dev, hisi_hba->debugfs_dq[dump_index][i].hdr);
> -
> -	for (i = 0; i < hisi_hba->queue_count; i++)
> -		devm_kfree(dev,
> -			   hisi_hba->debugfs_cq[dump_index][i].complete_hdr);
> -
> -	for (i = 0; i < DEBUGFS_REGS_NUM; i++)
> -		devm_kfree(dev, hisi_hba->debugfs_regs[dump_index][i].data);
> -
> -	for (i = 0; i < hisi_hba->n_phy; i++)
> -		devm_kfree(dev, hisi_hba->debugfs_port_reg[dump_index][i].data);
> -}
> -
>   static const struct hisi_sas_debugfs_reg *debugfs_reg_array_v3_hw[DEBUGFS_REGS_NUM] = {
>   	[DEBUGFS_GLOBAL] = &debugfs_global_reg,
>   	[DEBUGFS_AXI] = &debugfs_axi_reg,
> @@ -4206,7 +4182,7 @@ static int debugfs_alloc_v3_hw(struct hisi_hba *hisi_hba, int dump_index)
>   {
>   	const struct hisi_sas_hw *hw = hisi_hba->hw;
>   	struct device *dev = hisi_hba->dev;
> -	int p, c, d, r, i;
> +	int p, c, d, r;
>   	size_t sz;
>   
>   	for (r = 0; r < DEBUGFS_REGS_NUM; r++) {
> @@ -4286,8 +4262,6 @@ static int debugfs_alloc_v3_hw(struct hisi_hba *hisi_hba, int dump_index)
>   
>   	return 0;
>   fail:
> -	for (i = 0; i < hisi_sas_debugfs_dump_count; i++)
> -		debugfs_release_v3_hw(hisi_hba, i);
>   	return -ENOMEM;
>   }
>   
>