2024-05-23 13:19:59

by Ahmad Fatoum

Subject: [PATCH] docs: crypto: async-tx-api: fix broken code example

The code example fails to compile:

1) ddr_conv is defined twice, once as a VLA, which have been phased out

2) submit is not a pointer, but is still dereferenced with ->

Fix these issues and while at it, make the functions static as users
are unlikely to export them.

Fixes: 04ce9ab385dc ("async_xor: permit callers to pass in a 'dma/page scribble' region")
Signed-off-by: Ahmad Fatoum <[email protected]>
---
Documentation/crypto/async-tx-api.rst | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/crypto/async-tx-api.rst b/Documentation/crypto/async-tx-api.rst
index 27c146b54d71..2fa260f2a222 100644
--- a/Documentation/crypto/async-tx-api.rst
+++ b/Documentation/crypto/async-tx-api.rst
@@ -150,38 +150,38 @@ of an operation.
Perform a xor->copy->xor operation where each operation depends on the
result from the previous operation::

- void callback(void *param)
+ static void callback(void *param)
{
struct completion *cmp = param;

complete(cmp);
}

- void run_xor_copy_xor(struct page **xor_srcs,
- int xor_src_cnt,
- struct page *xor_dest,
- size_t xor_len,
- struct page *copy_src,
- struct page *copy_dest,
- size_t copy_len)
+ #define NDISKS 2
+
+ static void run_xor_copy_xor(struct page **xor_srcs,
+ struct page *xor_dest,
+ size_t xor_len,
+ struct page *copy_src,
+ struct page *copy_dest,
+ size_t copy_len)
{
struct dma_async_tx_descriptor *tx;
- addr_conv_t addr_conv[xor_src_cnt];
struct async_submit_ctl submit;
addr_conv_t addr_conv[NDISKS];
struct completion cmp;

init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST, NULL, NULL, NULL,
addr_conv);
- tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, &submit)
+ tx = async_xor(xor_dest, xor_srcs, 0, NDISKS, xor_len, &submit);

- submit->depend_tx = tx;
+ submit.depend_tx = tx;
tx = async_memcpy(copy_dest, copy_src, 0, 0, copy_len, &submit);

init_completion(&cmp);
init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST | ASYNC_TX_ACK, tx,
callback, &cmp, addr_conv);
- tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, &submit);
+ tx = async_xor(xor_dest, xor_srcs, 0, NDISKS, xor_len, &submit);

async_tx_issue_pending_all();


---
base-commit: a38297e3fb012ddfa7ce0321a7e5a8daeb1872b6
change-id: 20240523-async-dma-docs-00eb18a4e01c

Best regards,
--
Ahmad Fatoum <[email protected]>

2024-05-29 08:23:10

by Ahmad Fatoum

Subject: Re: [PATCH] docs: crypto: async-tx-api: fix broken code example

Hello Andre,

On 23.05.24 16:17, Andre Noll wrote:
> On Thu, May 23, 15:18, Ahmad Fatoum wrote
>> The code example fails to compile:
>>
>> 1) ddr_conv is defined twice, once as a VLA, which have been phased out
>
> addr_conv
>>
>> 2) submit is not a pointer, but is still dereferenced with ->
>
> 3) The first call to async_xor() lacked the trailing semicolon.
>
>> Fix these issues and while at it, make the functions static as users
>> are unlikely to export them.
>
> No objections, but please don't consider me authoritative. Two nits
> below, FWIW.

Oh, thanks for catching these. I just sent a v2 with your feedback
incorporated including the nitpicks.

Cheers,
Ahmad

>
>> --- a/Documentation/crypto/async-tx-api.rst
>> +++ b/Documentation/crypto/async-tx-api.rst
>> @@ -150,38 +150,38 @@ of an operation.
>> Perform a xor->copy->xor operation where each operation depends on the
>> result from the previous operation::
>
> Maybe add
>
> #include <linux/async_tx.h>
>
>>
>> - void callback(void *param)
>> + static void callback(void *param)
>> {
>> struct completion *cmp = param;
>>
>> complete(cmp);
>> }
>
> This could be simplified to
>
> static void callback(void *param)
> {
> complete(param);
> }
>
> Best
> Andre

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