diff mbox

[04/10] ata: add ata_is_fpdma() accessor

Message ID 1468454751-12466-5-git-send-email-hch@lst.de
State Not Applicable
Delegated to: David Miller
Headers show

Commit Message

Christoph Hellwig July 14, 2016, 12:05 a.m. UTC 
From: Hannes Reinecke <hare@suse.de>

Most of the SATA drivers (with the exception of ahci) don't know about
NCQ NON DATA commands, so they use the test for 'NCQ' as a shorthand for
'NCQ command with DMA data'.

With the introduction of the ATA_PROT_NODATA protocol variable these two
are no longer equivalent, as you can have NCQ commands without DMA.
As I haven't vetted any of those adapters for NCQ NON DATA commands, and
these driver internally also assume that any NCQ command will have
DMA-able data, I thought it prudent to introduce an ata_is_fpdma() flag,
which retains the original meaning of ata_is_ncq().

Signed-off-by: Hannes Reinecke <hare@suse.com>
[hch: changed ata_is_fpdma to return bool, updated patch description]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/ata/sata_fsl.c |  4 ++--
 drivers/ata/sata_mv.c  |  5 ++---
 drivers/ata/sata_nv.c  | 11 +++++------
 include/linux/libata.h |  6 ++++++
 4 files changed, 15 insertions(+), 11 deletions(-)

Comments

Tejun Heo July 14, 2016, 2:37 p.m. UTC | #1 
Hello,

I'm still a bit confused about this patch.

On Thu, Jul 14, 2016 at 09:05:45AM +0900, Christoph Hellwig wrote:
> diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
> index a723ae9..acfb865 100644
> --- a/drivers/ata/sata_fsl.c
> +++ b/drivers/ata/sata_fsl.c
> @@ -534,7 +534,7 @@ static void sata_fsl_qc_prep(struct ata_queued_cmd *qc)
>  	VPRINTK("Dumping cfis : 0x%x, 0x%x, 0x%x\n",
>  		cd->cfis[0], cd->cfis[1], cd->cfis[2]);
>  
> -	if (qc->tf.protocol == ATA_PROT_NCQ) {
> +	if (ata_is_fpdma(qc->tf.protocol)) {

ata_is_fpdma() tests NCQ or DMA.  Is this right?

> --- a/drivers/ata/sata_mv.c
> +++ b/drivers/ata/sata_mv.c
> @@ -1173,7 +1173,7 @@ static void mv_set_irq_coalescing(struct ata_host *host,
>  static void mv_start_edma(struct ata_port *ap, void __iomem *port_mmio,
>  			 struct mv_port_priv *pp, u8 protocol)
>  {
> -	int want_ncq = (protocol == ATA_PROT_NCQ);
> +	int want_ncq = (ata_is_fpdma(protocol));

Let's get rid of the parentheses while at it.

>  
>  	if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
>  		int using_ncq = ((pp->pp_flags & MV_PP_FLAG_NCQ_EN) != 0);
> @@ -2156,8 +2156,7 @@ static void mv_qc_prep_iie(struct ata_queued_cmd *qc)
>  	unsigned in_index;
>  	u32 flags = 0;
>  
> -	if ((tf->protocol != ATA_PROT_DMA) &&
> -	    (tf->protocol != ATA_PROT_NCQ))
> +	if (!ata_is_fpdma(tf->protocol))

This is actually testing !DMA && !NCQ and an equivalent conversion but
the rest aren't.

> diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
> index 734f563..89e36aa 100644
> --- a/drivers/ata/sata_nv.c
> +++ b/drivers/ata/sata_nv.c
> @@ -1407,7 +1407,7 @@ static void nv_adma_qc_prep(struct ata_queued_cmd *qc)
>  	cpb->next_cpb_idx	= 0;
>  
>  	/* turn on NCQ flags for NCQ commands */
> -	if (qc->tf.protocol == ATA_PROT_NCQ)
> +	if (ata_is_fpdma(qc->tf.protocol))
>  		ctl_flags |= NV_CPB_CTL_QUEUE | NV_CPB_CTL_FPDMA;

And I don't know why testing NCQ or DMA would be safe for places like
this.

> +	ATA_PROT_FLAG_FPDMA	= ATA_PROT_FLAG_NCQ | ATA_PROT_FLAG_DMA,
...
> +static inline bool ata_is_fpdma(u8 prot)
> +{
> +	return ata_prot_flags(prot) & ATA_PROT_FLAG_FPDMA;
> +}

???

Thanks.
Hannes Reinecke July 14, 2016, 3:15 p.m. UTC | #2 
On 07/14/2016 04:37 PM, Tejun Heo wrote:
> Hello,
> 
> I'm still a bit confused about this patch.
> 
> On Thu, Jul 14, 2016 at 09:05:45AM +0900, Christoph Hellwig wrote:
>> diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
>> index a723ae9..acfb865 100644
>> --- a/drivers/ata/sata_fsl.c
>> +++ b/drivers/ata/sata_fsl.c
>> @@ -534,7 +534,7 @@ static void sata_fsl_qc_prep(struct ata_queued_cmd *qc)
>>  	VPRINTK("Dumping cfis : 0x%x, 0x%x, 0x%x\n",
>>  		cd->cfis[0], cd->cfis[1], cd->cfis[2]);
>>  
>> -	if (qc->tf.protocol == ATA_PROT_NCQ) {
>> +	if (ata_is_fpdma(qc->tf.protocol)) {
> 
> ata_is_fpdma() tests NCQ or DMA.  Is this right?
> 
Yes. The 'sata_fsl' driver has no means (or at least none which I could
detect) allowing it to send NCQ NON-DATA commands.
So for this driver the check for ncq is actually a check for fpdma.

>> --- a/drivers/ata/sata_mv.c
>> +++ b/drivers/ata/sata_mv.c
>> @@ -1173,7 +1173,7 @@ static void mv_set_irq_coalescing(struct ata_host *host,
>>  static void mv_start_edma(struct ata_port *ap, void __iomem *port_mmio,
>>  			 struct mv_port_priv *pp, u8 protocol)
>>  {
>> -	int want_ncq = (protocol == ATA_PROT_NCQ);
>> +	int want_ncq = (ata_is_fpdma(protocol));
> 
> Let's get rid of the parentheses while at it.
> 
Okay.

>>  
>>  	if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
>>  		int using_ncq = ((pp->pp_flags & MV_PP_FLAG_NCQ_EN) != 0);
>> @@ -2156,8 +2156,7 @@ static void mv_qc_prep_iie(struct ata_queued_cmd *qc)
>>  	unsigned in_index;
>>  	u32 flags = 0;
>>  
>> -	if ((tf->protocol != ATA_PROT_DMA) &&
>> -	    (tf->protocol != ATA_PROT_NCQ))
>> +	if (!ata_is_fpdma(tf->protocol))
> 
> This is actually testing !DMA && !NCQ and an equivalent conversion but
> the rest aren't.
> 
Yes.

>> diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
>> index 734f563..89e36aa 100644
>> --- a/drivers/ata/sata_nv.c
>> +++ b/drivers/ata/sata_nv.c
>> @@ -1407,7 +1407,7 @@ static void nv_adma_qc_prep(struct ata_queued_cmd *qc)
>>  	cpb->next_cpb_idx	= 0;
>>  
>>  	/* turn on NCQ flags for NCQ commands */
>> -	if (qc->tf.protocol == ATA_PROT_NCQ)
>> +	if (ata_is_fpdma(qc->tf.protocol))
>>  		ctl_flags |= NV_CPB_CTL_QUEUE | NV_CPB_CTL_FPDMA;
> 
> And I don't know why testing NCQ or DMA would be safe for places like
> this.
> 
Again, this driver cannot handle NCQ NON-DATA command, so it always has
to assume that NCQ _actually_ means FPDMA.

>> +	ATA_PROT_FLAG_FPDMA	= ATA_PROT_FLAG_NCQ | ATA_PROT_FLAG_DMA,
> ...
>> +static inline bool ata_is_fpdma(u8 prot)
>> +{
>> +	return ata_prot_flags(prot) & ATA_PROT_FLAG_FPDMA;
>> +}
> 
> ???
> 
Yeah, strictly speaking there is no need for ATA_PROT_FLAG_FPDMA.
I'll be removing it if you insist.

Cheers,

Hannes

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Tejun Heo July 14, 2016, 3:19 p.m. UTC | #3 
Hello, Hannes.

On Thu, Jul 14, 2016 at 05:15:51PM +0200, Hannes Reinecke wrote:
> >> +static inline bool ata_is_fpdma(u8 prot)
> >> +{
> >> +	return ata_prot_flags(prot) & ATA_PROT_FLAG_FPDMA;
> >> +}
> > 
> > ???
> > 
> Yeah, strictly speaking there is no need for ATA_PROT_FLAG_FPDMA.
> I'll be removing it if you insist.

No, it's just really confusing to have a function named ata_is_fpdma()
and then have it test whether the protocol is NCQ or DMA.  If you
wanna do that, name it ata_is_dma_or_fpdma().  ata_is_fpdma() should
test (prot & ATA_PROT_FLAG_FPDMA) == ATA_PROT_FLAG_FPDMA.

Thanks.
Hannes Reinecke July 14, 2016, 4:01 p.m. UTC | #4 
On 07/14/2016 05:19 PM, Tejun Heo wrote:
> Hello, Hannes.
> 
> On Thu, Jul 14, 2016 at 05:15:51PM +0200, Hannes Reinecke wrote:
>>>> +static inline bool ata_is_fpdma(u8 prot)
>>>> +{
>>>> +	return ata_prot_flags(prot) & ATA_PROT_FLAG_FPDMA;
>>>> +}
>>>
>>> ???
>>>
>> Yeah, strictly speaking there is no need for ATA_PROT_FLAG_FPDMA.
>> I'll be removing it if you insist.
> 
> No, it's just really confusing to have a function named ata_is_fpdma()
> and then have it test whether the protocol is NCQ or DMA.  If you
> wanna do that, name it ata_is_dma_or_fpdma().  ata_is_fpdma() should
> test (prot & ATA_PROT_FLAG_FPDMA) == ATA_PROT_FLAG_FPDMA.
> 
Ah. Now I see your point.

That was unintentional, and your suggestion is in fact correct.
I'll be fixing it up.

Cheers,

Hannes
Christoph Hellwig July 15, 2016, 6:13 a.m. UTC | #5 
Hi Rejun, hi Hannes,

Damien and I spent some time going over this patch today and we think
it's best to simply drop it.  
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Hannes Reinecke July 15, 2016, 7:07 a.m. UTC | #6 
On 07/15/2016 08:13 AM, Christoph Hellwig wrote:
> Hi Rejun, hi Hannes,
> 
> Damien and I spent some time going over this patch today and we think
> it's best to simply drop it.  
> 
Sure, fine with me.

Cheers,

Hannes
Christoph Hellwig July 15, 2016, 7:26 a.m. UTC | #7 
On Fri, Jul 15, 2016 at 09:07:30AM +0200, Hannes Reinecke wrote:
> > Damien and I spent some time going over this patch today and we think
> > it's best to simply drop it.  
> > 
> Sure, fine with me.

Great.  I've verified that the remaining patches will apply and work
fine when simply dropping it.
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diff mbox

Patch

diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
index a723ae9..acfb865 100644
--- a/drivers/ata/sata_fsl.c
+++ b/drivers/ata/sata_fsl.c
@@ -534,7 +534,7 @@  static void sata_fsl_qc_prep(struct ata_queued_cmd *qc)
 	VPRINTK("Dumping cfis : 0x%x, 0x%x, 0x%x\n",
 		cd->cfis[0], cd->cfis[1], cd->cfis[2]);
 
-	if (qc->tf.protocol == ATA_PROT_NCQ) {
+	if (ata_is_fpdma(qc->tf.protocol)) {
 		VPRINTK("FPDMA xfer,Sctor cnt[0:7],[8:15] = %d,%d\n",
 			cd->cfis[3], cd->cfis[11]);
 	}
@@ -551,7 +551,7 @@  static void sata_fsl_qc_prep(struct ata_queued_cmd *qc)
 					    &ttl_dwords, cd_paddr,
 					    host_priv->data_snoop);
 
-	if (qc->tf.protocol == ATA_PROT_NCQ)
+	if (ata_is_fpdma(qc->tf.protocol))
 		desc_info |= FPDMA_QUEUED_CMD;
 
 	sata_fsl_setup_cmd_hdr_entry(pp, tag, desc_info, ttl_dwords,
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index bd74ee5..a81b1f8 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -1173,7 +1173,7 @@  static void mv_set_irq_coalescing(struct ata_host *host,
 static void mv_start_edma(struct ata_port *ap, void __iomem *port_mmio,
 			 struct mv_port_priv *pp, u8 protocol)
 {
-	int want_ncq = (protocol == ATA_PROT_NCQ);
+	int want_ncq = (ata_is_fpdma(protocol));
 
 	if (pp->pp_flags & MV_PP_FLAG_EDMA_EN) {
 		int using_ncq = ((pp->pp_flags & MV_PP_FLAG_NCQ_EN) != 0);
@@ -2156,8 +2156,7 @@  static void mv_qc_prep_iie(struct ata_queued_cmd *qc)
 	unsigned in_index;
 	u32 flags = 0;
 
-	if ((tf->protocol != ATA_PROT_DMA) &&
-	    (tf->protocol != ATA_PROT_NCQ))
+	if (!ata_is_fpdma(tf->protocol))
 		return;
 	if (tf->command == ATA_CMD_DSM)
 		return;  /* use bmdma for this */
diff --git a/drivers/ata/sata_nv.c b/drivers/ata/sata_nv.c
index 734f563..89e36aa 100644
--- a/drivers/ata/sata_nv.c
+++ b/drivers/ata/sata_nv.c
@@ -1407,7 +1407,7 @@  static void nv_adma_qc_prep(struct ata_queued_cmd *qc)
 	cpb->next_cpb_idx	= 0;
 
 	/* turn on NCQ flags for NCQ commands */
-	if (qc->tf.protocol == ATA_PROT_NCQ)
+	if (ata_is_fpdma(qc->tf.protocol))
 		ctl_flags |= NV_CPB_CTL_QUEUE | NV_CPB_CTL_FPDMA;
 
 	VPRINTK("qc->flags = 0x%lx\n", qc->flags);
@@ -1432,15 +1432,14 @@  static unsigned int nv_adma_qc_issue(struct ata_queued_cmd *qc)
 {
 	struct nv_adma_port_priv *pp = qc->ap->private_data;
 	void __iomem *mmio = pp->ctl_block;
-	int curr_ncq = (qc->tf.protocol == ATA_PROT_NCQ);
+	int curr_ncq = ata_is_fpdma(qc->tf.protocol);
 
 	VPRINTK("ENTER\n");
 
 	/* We can't handle result taskfile with NCQ commands, since
 	   retrieving the taskfile switches us out of ADMA mode and would abort
 	   existing commands. */
-	if (unlikely(qc->tf.protocol == ATA_PROT_NCQ &&
-		     (qc->flags & ATA_QCFLAG_RESULT_TF))) {
+	if (unlikely(curr_ncq && (qc->flags & ATA_QCFLAG_RESULT_TF))) {
 		ata_dev_err(qc->dev, "NCQ w/ RESULT_TF not allowed\n");
 		return AC_ERR_SYSTEM;
 	}
@@ -1991,7 +1990,7 @@  static int nv_swncq_port_start(struct ata_port *ap)
 
 static void nv_swncq_qc_prep(struct ata_queued_cmd *qc)
 {
-	if (qc->tf.protocol != ATA_PROT_NCQ) {
+	if (!ata_is_fpdma(qc->tf.protocol)) {
 		ata_bmdma_qc_prep(qc);
 		return;
 	}
@@ -2067,7 +2066,7 @@  static unsigned int nv_swncq_qc_issue(struct ata_queued_cmd *qc)
 	struct ata_port *ap = qc->ap;
 	struct nv_swncq_port_priv *pp = ap->private_data;
 
-	if (qc->tf.protocol != ATA_PROT_NCQ)
+	if (!ata_is_fpdma(qc->tf.protocol))
 		return ata_bmdma_qc_issue(qc);
 
 	DPRINTK("Enter\n");
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 4e5a09c..77833f6 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -152,6 +152,7 @@  enum {
 	ATA_PROT_FLAG_DATA	= ATA_PROT_FLAG_PIO | ATA_PROT_FLAG_DMA,
 	ATA_PROT_FLAG_NCQ	= (1 << 2), /* is NCQ */
 	ATA_PROT_FLAG_ATAPI	= (1 << 3), /* is ATAPI */
+	ATA_PROT_FLAG_FPDMA	= ATA_PROT_FLAG_NCQ | ATA_PROT_FLAG_DMA,
 
 	/* struct ata_device stuff */
 	ATA_DFLAG_LBA		= (1 << 0), /* device supports LBA */
@@ -1093,6 +1094,11 @@  static inline bool ata_is_data(u8 prot)
 	return ata_prot_flags(prot) & ATA_PROT_FLAG_DATA;
 }
 
+static inline bool ata_is_fpdma(u8 prot)
+{
+	return ata_prot_flags(prot) & ATA_PROT_FLAG_FPDMA;
+}
+
 static inline int is_multi_taskfile(struct ata_taskfile *tf)
 {
 	return (tf->command == ATA_CMD_READ_MULTI) ||