Re: [PATCH v2 11/20] s390/zcrypt/pkey: Rework ep11 findcard() implementation and callers

Harald Freudenberger
2025-03-25T13:12:29Z

On 2025-03-20 09:30, Holger Dengler wrote:
> On 04/03/2025 18:21, Harald Freudenberger wrote:
>> Rework the memory usage of the ep11 findcard() implementation:
>> - findcard does not allocate memory for the list of apqns
>> any more.
>> - the callers are now responsible to provide an array of
>> apqns to store the matching apqns into.
>
> See my comments below.
>
>>
>> Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
>> ---
>> drivers/s390/crypto/pkey_ep11.c | 19 ++++++++-----------
>> drivers/s390/crypto/zcrypt_ep11misc.c | 18 ++++--------------
>> drivers/s390/crypto/zcrypt_ep11misc.h | 12 +++++-------
>> 3 files changed, 17 insertions(+), 32 deletions(-)
>>
> [...]
>> diff --git a/drivers/s390/crypto/zcrypt_ep11misc.c
>> b/drivers/s390/crypto/zcrypt_ep11misc.c
>> index 04153b476168..6005ef79c001 100644
>> --- a/drivers/s390/crypto/zcrypt_ep11misc.c
>> +++ b/drivers/s390/crypto/zcrypt_ep11misc.c
> [...]
>> @@ -1678,17 +1671,14 @@ int ep11_findcard2(u32 **apqns, u32 *nr_apqns,
>> u16 cardnr, u16 domain,
>> continue;
>> }
>> /* apqn passed all filtering criterons, add to the array */
>> - if (_nr_apqns < 256)
>> - _apqns[_nr_apqns++] = (((u16)card) << 16) | ((u16)dom);
>> + if (_nr_apqns < *nr_apqns)
>> + apqns[_nr_apqns++] = (((u16)card) << 16) | ((u16)dom);
>> }
>>
>> /* nothing found ? */
>> if (!_nr_apqns) {
>> - kfree(_apqns);
>> rc = -ENODEV;
>> } else {
>> - /* no re-allocation, simple return the _apqns array */
>> - *apqns = _apqns;
>
> Please update *apqns unconditionally.
>
>> *nr_apqns = _nr_apqns;
>> rc = 0;
>> }
>> diff --git a/drivers/s390/crypto/zcrypt_ep11misc.h
>> b/drivers/s390/crypto/zcrypt_ep11misc.h
>> index a4b98eca8431..cbd615547bc2 100644
>> --- a/drivers/s390/crypto/zcrypt_ep11misc.h
>> +++ b/drivers/s390/crypto/zcrypt_ep11misc.h
>> @@ -136,14 +136,12 @@ int ep11_clr2keyblob(u16 cardnr, u16 domain, u32
>> keybitsize, u32 keygenflags,
>> * key for this domain. When a wkvp is given there will always be a
>> re-fetch
>> * of the domain info for the potential apqn - so this triggers an
>> request
>> * reply to each apqn eligible.
>> - * The array of apqn entries is allocated with kmalloc and returned
>> in *apqns;
>> - * the number of apqns stored into the list is returned in *nr_apqns.
>> One apqn
>> - * entry is simple a 32 bit value with 16 bit cardnr and 16 bit
>> domain nr and
>> - * may be casted to struct pkey_apqn. The return value is either 0
>> for success
>> - * or a negative errno value. If no apqn meeting the criteria is
>> found,
>> - * -ENODEV is returned.
>> + * The caller should set *nr_apqns to the nr of elements available in
>> *apqns.
>> + * On return *nr_apqns is then updated with the nr of apqns filled
>> into *apqns.
>> + * The return value is either 0 for success or a negative errno
>> value.
>> + * If no apqn meeting the criteria is found, -ENODEV is returned.
>
> As mentioned in my comment to patch 10/20: please update nr_apqns in
> any case. If -ENODEV should be dropped for cca, than also drop it
> here.
>
>> */
>> -int ep11_findcard2(u32 **apqns, u32 *nr_apqns, u16 cardnr, u16
>> domain,
>> +int ep11_findcard2(u32 *apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
>> int minhwtype, int minapi, const u8 *wkvp);
>>
>> /*

The *nr_apqns is now unconditional updated. But I keep the behavior with
the -ENODEV as there is code relaying on that.
-> v3