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Subject: Re: [PATCH 2/2] scsi: ufs: Return a bsg request immediatley if
 eh-in-progress
To:     Avri Altman <avri.altman@wdc.com>,
        "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Adrian Hunter <adrian.hunter@intel.com>
References: <20211108120804.10405-1-avri.altman@wdc.com>
 <20211108120804.10405-3-avri.altman@wdc.com>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <fa7dae1f-06ac-9d5a-616d-cc00c38e5feb@acm.org>
Date:   Mon, 8 Nov 2021 09:16:48 -0800
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On 11/8/21 4:08 AM, Avri Altman wrote:
> ufs-bsg is attempting to access the device from user-space, and it is
> unaware of the internal driver flows, specifically if error handling is
> currently ongoing.
> 
> Fixes: 5e0a86eed846 (scsi: ufs: Add API to execute raw upiu commands)
> 
> Signed-off-by: Avri Altman <avri.altman@wdc.com>
> ---
>   drivers/scsi/ufs/ufshcd.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 3869bb57769b..828061c05909 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -6830,6 +6830,9 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
>   	enum utp_ocs ocs_value;
>   	u8 tm_f = be32_to_cpu(req_upiu->header.dword_1) >> 16 & MASK_TM_FUNC;
>   
> +	if (!ufshcd_is_user_access_allowed(hba))
> +		return -EBUSY;
> +
>   	switch (msgcode) {
>   	case UPIU_TRANSACTION_NOP_OUT:
>   		cmd_type = DEV_CMD_TYPE_NOP;

Making operations fail if error handling is in progress makes it harder than
necessary to write user space software that uses the BSG interface. Has it
been considered to wait inside ufshcd_exec_raw_upiu_cmd() until error handling
has finished?

Thanks,

Bart.