RE: [PATCH 2/2] scsi: ufs: add inline crypto support to UFS HCD

[Parshuram Raju Thombare]

Hello Greg,

Thank you for comments.

>-----Original Message-----
>From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
>Sent: Tuesday, December 11, 2018 5:34 PM
>To: Parshuram Raju Thombare <pthombar@xxxxxxxxxxx>
>Cc: axboe@xxxxxxxxx; vinholikatti@xxxxxxxxx; jejb@xxxxxxxxxxxxxxxxxx;
>martin.petersen@xxxxxxxxxx; mchehab+samsung@xxxxxxxxxx;
>davem@xxxxxxxxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx;
>nicolas.ferre@xxxxxxxxxxxxx; arnd@xxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
>linux-block@xxxxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; Alan Douglas
><adouglas@xxxxxxxxxxx>; Janek Kotas <jank@xxxxxxxxxxx>; Rafal Ciepiela
><rafalc@xxxxxxxxxxx>
>Subject: Re: [PATCH 2/2] scsi: ufs: add inline crypto support to UFS HCD
>
>EXTERNAL MAIL
>
>
>On Tue, Dec 11, 2018 at 09:50:27AM +0000, Parshuram Thombare wrote:
>> Add real time crypto support to UFS HCD using new device mapper
>> 'crypto-ufs'. dmsetup tool can be used to enable real time / inline
>> crypto support using device mapper 'crypt-ufs'.
>>
>> Signed-off-by: Parshuram Thombare <pthombar@xxxxxxxxxxx>
>
>As you cc:ed me, I'll provide some minor review comments:
>
>> +config BLK_DEV_HW_RT_ENCRYPTION
>> +	bool
>> +	depends on SCSI_UFSHCD_RT_ENCRYPTION
>> +	default n
>
>n is always the default, you never need to list that.
Ok,  I will remove it.
>
>> +
>>  source block/Kconfig.iosched
>> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig index
>> 2ddbb26..09a3ec0 100644
>> --- a/drivers/scsi/ufs/Kconfig
>> +++ b/drivers/scsi/ufs/Kconfig
>> @@ -136,3 +136,15 @@ config SCSI_UFS_BSG
>>
>>  	  Select this if you need a bsg device node for your UFS controller.
>>  	  If unsure, say N.
>> +
>> +config SCSI_UFSHCD_RT_ENCRYPTION
>> +	bool "Universal Flash Storage Controller RT encryption support"
>> +	depends on SCSI_UFSHCD
>> +	default n
>
>Same here.
>
Ok,  I will remove it.
>> +	select BLK_DEV_HW_RT_ENCRYPTION if SCSI_UFSHCD_RT_ENCRYPTION
>> +	select BLK_DEV_DM if SCSI_UFSHCD_RT_ENCRYPTION
>> +	help
>> +	Universal Flash Storage Controller RT encryption support
>> +
>> +	Select this if you want to enable real time encryption on UFS controller
>> +	If unsure, say N.
>
>Don't you need to indent the help lines?
>
Sorry, missed indentation check here. I will indent this.
>> +int ufshcd_crypto_init(struct ufs_hba *hba); void
>> +ufshcd_crypto_remove(struct ufs_hba *hba); void
>> +ufshcd_prepare_for_crypto(struct ufs_hba *hba, struct ufshcd_lrb
>> +*lrbp); #endif
>
>You need to provide inline functions for when your config option is not enabled
>here.
>
>That way you don't have to do this mess:
>
Do you mean empty inline function (which are exported) in #else  to avoid #ifdef 
around each call for these functions ?
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index 86fe114..a96b038 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -47,6 +47,9 @@
>>  #include "unipro.h"
>>  #include "ufs-sysfs.h"
>>  #include "ufs_bsg.h"
>> +#ifdef CONFIG_SCSI_UFSHCD_RT_ENCRYPTION #include "ufshcd-crypto.h"
>> +#endif
>
>No need for #ifdefs in .c files at all.  Always include the .h file, and then since your
>functions are all inline void functions, the code just compiles away into nothing.
>
>
Ok,  I will remove it.
>>
>>  #define CREATE_TRACE_POINTS
>>  #include <trace/events/ufs.h>
>> @@ -2198,6 +2201,14 @@ static void ufshcd_prepare_req_desc_hdr(struct
>> ufshcd_lrb *lrbp,
>>
>>  	dword_0 = data_direction | (lrbp->command_type
>>  				<< UPIU_COMMAND_TYPE_OFFSET);
>> +#ifdef CONFIG_SCSI_UFSHCD_RT_ENCRYPTION
>> +	if (lrbp->cci >= 0) {
>> +		dword_0 |= (1 <<
>CRYPTO_UTP_REQ_DESC_DWORD0_CE_SHIFT);
>> +		dword_0 |= ((lrbp->cci <<
>CRYPTO_UTP_REQ_DESC_DWORD0_CCI_SHIFT)
>> +				&
>CRYPTO_UTP_REQ_DESC_DWORD0_CCI_MASK);
>> +	} else
>> +		dword_0 &= ~CRYPTO_UTP_REQ_DESC_DWORD0_CE_MASK;
>> +#endif
>
>Some comments on what this is trying to do here?
>
>
This is to enable encryption by setting CCI (crypto config index) and CE crypto enable bit.
I will add comment here.
>>  	if (lrbp->intr_cmd)
>>  		dword_0 |= UTP_REQ_DESC_INT_CMD;
>>
>> @@ -2462,6 +2473,12 @@ static int ufshcd_queuecommand(struct Scsi_Host
>*host, struct scsi_cmnd *cmd)
>>  	lrbp->intr_cmd = !ufshcd_is_intr_aggr_allowed(hba) ? true : false;
>>  	lrbp->req_abort_skip = false;
>>
>> +#ifdef CONFIG_SCSI_UFSHCD_RT_ENCRYPTION
>> +	lrbp->cci = -1;
>
>What does -1 mean?  You should have a type for it if it is something "special".
>
-1 means crypto is not enabled or supported by hardware. I think this need a comment.
I will add it.
>> +	/* prepare block for crypto */
>> +	if (hba->capabilities & MASK_CRYPTO_SUPPORT)
>> +		ufshcd_prepare_for_crypto(hba, lrbp); #endif
>
>Again, no #ifdefs needed please.
>
>
Ok, I will remove it.
>>  	ufshcd_comp_scsi_upiu(hba, lrbp);
>>
>>  	err = ufshcd_map_sg(hba, lrbp);
>> @@ -8119,6 +8136,11 @@ void ufshcd_remove(struct ufs_hba *hba)
>>  	ufs_bsg_remove(hba);
>>  	ufs_sysfs_remove_nodes(hba->dev);
>>  	scsi_remove_host(hba->host);
>> +#ifdef CONFIG_SCSI_UFSHCD_RT_ENCRYPTION
>> +	if (hba->capabilities & MASK_CRYPTO_SUPPORT)
>> +		ufshcd_crypto_remove(hba);
>> +#endif
>
>Same ifdef here, and everywhere else in this file.
>
Ok, I will remove it.
>> --- a/drivers/scsi/ufs/ufshcd.h
>> +++ b/drivers/scsi/ufs/ufshcd.h
>> @@ -193,6 +193,9 @@ struct ufshcd_lrb {
>>  	ktime_t compl_time_stamp;
>>
>>  	bool req_abort_skip;
>> +#ifdef CONFIG_SCSI_UFSHCD_RT_ENCRYPTION
>> +	int cci;
>> +#endif
>
>No need for a #ifdef here.  But comment on exactly what "cci" means, that seems
>to not make any sense to me.
>
CCI is crypto config index / slot in UFS. I will add a comment here.
>>  };
>>
>>  /**
>> @@ -706,6 +709,9 @@ struct ufs_hba {
>>
>>  	struct device		bsg_dev;
>>  	struct request_queue	*bsg_queue;
>> +#ifdef CONFIG_SCSI_UFSHCD_RT_ENCRYPTION
>> +	struct ufshcd_crypto_ctx *cctx;
>> +#endif
>
>or here.
>
Ok, I will remove it.
>>  };
>>
>>  /* Returns true if clocks can be gated. Otherwise false */ diff --git
>> a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h index
>> 6fa889d..fe5a92d 100644
>> --- a/drivers/scsi/ufs/ufshci.h
>> +++ b/drivers/scsi/ufs/ufshci.h
>> @@ -90,6 +90,7 @@ enum {
>>  	MASK_64_ADDRESSING_SUPPORT		= 0x01000000,
>>  	MASK_OUT_OF_ORDER_DATA_DELIVERY_SUPPORT	= 0x02000000,
>>  	MASK_UIC_DME_TEST_MODE_SUPPORT		= 0x04000000,
>> +	MASK_CRYPTO_SUPPORT                     = 0x10000000,
>
>Why are you all not using the BIT(N) macro for these?
Yes, I will replace it with BIT(N).
>
>thanks,
>
>greg k-h

Regards,
Parshuram Thombare