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[PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

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  [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-25 20:40 +0200
    Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map  helper function Herbert Xu <herbert@gondor.apana.org.au> - 2017-04-27 06:00 +0200
      Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map  helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-27 17:50 +0200
        Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map  helper function Herbert Xu <herbert@gondor.apana.org.au> - 2017-04-28 08:40 +0200
          Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map  helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-28 19:00 +0200
            Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map  helper function Herbert Xu <herbert@gondor.apana.org.au> - 2017-04-28 20:40 +0200
              Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map  helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-28 21:10 +0200

#1630891 — [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

Very straightforward conversion to the new function in the caam driver
and shash library.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
---
 crypto/shash.c                | 9 ++++++---
 drivers/crypto/caam/caamalg.c | 8 +++-----
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/crypto/shash.c b/crypto/shash.c
index 5e31c8d..5914881 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -283,10 +283,13 @@ int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
 	if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
 		void *data;
 
-		data = kmap_atomic(sg_page(sg));
-		err = crypto_shash_digest(desc, data + offset, nbytes,
+		data = sg_map(sg, 0, SG_KMAP_ATOMIC);
+		if (IS_ERR(data))
+			return PTR_ERR(data);
+
+		err = crypto_shash_digest(desc, data, nbytes,
 					  req->result);
-		kunmap_atomic(data);
+		sg_unmap(sg, data, 0, SG_KMAP_ATOMIC);
 		crypto_yield(desc->flags);
 	} else
 		err = crypto_shash_init(desc) ?:
diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index 398807d..62d2f5d 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -89,7 +89,6 @@ static void dbg_dump_sg(const char *level, const char *prefix_str,
 			struct scatterlist *sg, size_t tlen, bool ascii)
 {
 	struct scatterlist *it;
-	void *it_page;
 	size_t len;
 	void *buf;
 
@@ -98,19 +97,18 @@ static void dbg_dump_sg(const char *level, const char *prefix_str,
 		 * make sure the scatterlist's page
 		 * has a valid virtual memory mapping
 		 */
-		it_page = kmap_atomic(sg_page(it));
-		if (unlikely(!it_page)) {
+		buf = sg_map(it, 0, SG_KMAP_ATOMIC);
+		if (IS_ERR(buf)) {
 			printk(KERN_ERR "dbg_dump_sg: kmap failed\n");
 			return;
 		}
 
-		buf = it_page + it->offset;
 		len = min_t(size_t, tlen, it->length);
 		print_hex_dump(level, prefix_str, prefix_type, rowsize,
 			       groupsize, buf, len, ascii);
 		tlen -= len;
 
-		kunmap_atomic(it_page);
+		sg_unmap(it, buf, 0, SG_KMAP_ATOMIC);
 	}
 }
 #endif
-- 
2.1.4

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#1631849 — Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

On Tue, Apr 25, 2017 at 12:20:54PM -0600, Logan Gunthorpe wrote:
> Very straightforward conversion to the new function in the caam driver
> and shash library.
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: "David S. Miller" <davem@davemloft.net>
> ---
>  crypto/shash.c                | 9 ++++++---
>  drivers/crypto/caam/caamalg.c | 8 +++-----
>  2 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/crypto/shash.c b/crypto/shash.c
> index 5e31c8d..5914881 100644
> --- a/crypto/shash.c
> +++ b/crypto/shash.c
> @@ -283,10 +283,13 @@ int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
>  	if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
>  		void *data;
>  
> -		data = kmap_atomic(sg_page(sg));
> -		err = crypto_shash_digest(desc, data + offset, nbytes,
> +		data = sg_map(sg, 0, SG_KMAP_ATOMIC);
> +		if (IS_ERR(data))
> +			return PTR_ERR(data);
> +
> +		err = crypto_shash_digest(desc, data, nbytes,
>  					  req->result);
> -		kunmap_atomic(data);
> +		sg_unmap(sg, data, 0, SG_KMAP_ATOMIC);
>  		crypto_yield(desc->flags);
>  	} else
>  		err = crypto_shash_init(desc) ?:

Nack.  This is an optimisation for the special case of a single
SG list entry.  In fact in the common case the kmap_atomic should
disappear altogether in the no-highmem case.  So replacing it
with sg_map is not acceptable.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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#1632195 — Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

On 26/04/17 09:56 PM, Herbert Xu wrote:
> On Tue, Apr 25, 2017 at 12:20:54PM -0600, Logan Gunthorpe wrote:
>> Very straightforward conversion to the new function in the caam driver
>> and shash library.
>>
>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>> Cc: Herbert Xu <herbert@gondor.apana.org.au>
>> Cc: "David S. Miller" <davem@davemloft.net>
>> ---
>>  crypto/shash.c                | 9 ++++++---
>>  drivers/crypto/caam/caamalg.c | 8 +++-----
>>  2 files changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/crypto/shash.c b/crypto/shash.c
>> index 5e31c8d..5914881 100644
>> --- a/crypto/shash.c
>> +++ b/crypto/shash.c
>> @@ -283,10 +283,13 @@ int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
>>  	if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
>>  		void *data;
>>  
>> -		data = kmap_atomic(sg_page(sg));
>> -		err = crypto_shash_digest(desc, data + offset, nbytes,
>> +		data = sg_map(sg, 0, SG_KMAP_ATOMIC);
>> +		if (IS_ERR(data))
>> +			return PTR_ERR(data);
>> +
>> +		err = crypto_shash_digest(desc, data, nbytes,
>>  					  req->result);
>> -		kunmap_atomic(data);
>> +		sg_unmap(sg, data, 0, SG_KMAP_ATOMIC);
>>  		crypto_yield(desc->flags);
>>  	} else
>>  		err = crypto_shash_init(desc) ?:
> 
> Nack.  This is an optimisation for the special case of a single
> SG list entry.  In fact in the common case the kmap_atomic should
> disappear altogether in the no-highmem case.  So replacing it
> with sg_map is not acceptable.

What you seem to have missed is that sg_map is just a thin wrapper
around kmap_atomic. Perhaps with a future check for a mappable page.
This change should have zero impact on performance.

Logan

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#1632559 — Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

On Thu, Apr 27, 2017 at 09:45:57AM -0600, Logan Gunthorpe wrote:
> 
> 
> On 26/04/17 09:56 PM, Herbert Xu wrote:
> > On Tue, Apr 25, 2017 at 12:20:54PM -0600, Logan Gunthorpe wrote:
> >> Very straightforward conversion to the new function in the caam driver
> >> and shash library.
> >>
> >> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> >> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> >> Cc: "David S. Miller" <davem@davemloft.net>
> >> ---
> >>  crypto/shash.c                | 9 ++++++---
> >>  drivers/crypto/caam/caamalg.c | 8 +++-----
> >>  2 files changed, 9 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/crypto/shash.c b/crypto/shash.c
> >> index 5e31c8d..5914881 100644
> >> --- a/crypto/shash.c
> >> +++ b/crypto/shash.c
> >> @@ -283,10 +283,13 @@ int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
> >>  	if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
> >>  		void *data;
> >>  
> >> -		data = kmap_atomic(sg_page(sg));
> >> -		err = crypto_shash_digest(desc, data + offset, nbytes,
> >> +		data = sg_map(sg, 0, SG_KMAP_ATOMIC);
> >> +		if (IS_ERR(data))
> >> +			return PTR_ERR(data);
> >> +
> >> +		err = crypto_shash_digest(desc, data, nbytes,
> >>  					  req->result);
> >> -		kunmap_atomic(data);
> >> +		sg_unmap(sg, data, 0, SG_KMAP_ATOMIC);
> >>  		crypto_yield(desc->flags);
> >>  	} else
> >>  		err = crypto_shash_init(desc) ?:
> > 
> > Nack.  This is an optimisation for the special case of a single
> > SG list entry.  In fact in the common case the kmap_atomic should
> > disappear altogether in the no-highmem case.  So replacing it
> > with sg_map is not acceptable.
> 
> What you seem to have missed is that sg_map is just a thin wrapper
> around kmap_atomic. Perhaps with a future check for a mappable page.
> This change should have zero impact on performance.

You are right.  Indeed the existing code looks buggy as they
don't take sg->offset into account when doing the kmap.  Could
you send me some patches that fix these problems first so that
they can be easily backported?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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#1633026 — Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

On 28/04/17 12:30 AM, Herbert Xu wrote:
> You are right.  Indeed the existing code looks buggy as they
> don't take sg->offset into account when doing the kmap.  Could
> you send me some patches that fix these problems first so that
> they can be easily backported?

Ok, I think the only buggy one in crypto is hifn_795x. Shash and caam
both do have the sg->offset accounted for. I'll send a patch for the
buggy one shortly.

Logan

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#1633084 — Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

On Fri, Apr 28, 2017 at 10:53:45AM -0600, Logan Gunthorpe wrote:
> 
> 
> On 28/04/17 12:30 AM, Herbert Xu wrote:
> > You are right.  Indeed the existing code looks buggy as they
> > don't take sg->offset into account when doing the kmap.  Could
> > you send me some patches that fix these problems first so that
> > they can be easily backported?
> 
> Ok, I think the only buggy one in crypto is hifn_795x. Shash and caam
> both do have the sg->offset accounted for. I'll send a patch for the
> buggy one shortly.

I think they're all buggy when sg->offset is greater than PAGE_SIZE.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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#1633092 — Re: [PATCH v2 07/21] crypto: shash, caam: Make use of the new sg_map helper function

On 28/04/17 11:51 AM, Herbert Xu wrote:
> On Fri, Apr 28, 2017 at 10:53:45AM -0600, Logan Gunthorpe wrote:
>>
>>
>> On 28/04/17 12:30 AM, Herbert Xu wrote:
>>> You are right.  Indeed the existing code looks buggy as they
>>> don't take sg->offset into account when doing the kmap.  Could
>>> you send me some patches that fix these problems first so that
>>> they can be easily backported?
>>
>> Ok, I think the only buggy one in crypto is hifn_795x. Shash and caam
>> both do have the sg->offset accounted for. I'll send a patch for the
>> buggy one shortly.
> 
> I think they're all buggy when sg->offset is greater than PAGE_SIZE.

Yes, technically. But that's a _very_ common mistake. Pretty nearly
every case I looked at did not take that into account. I don't think
sg's that point to more than one continuous page are all that common.

Fixing all those cases without making a common function is a waste of
time IMO.

Logan

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