Re: [dpdk-dev] [PATCH v3] mempool: return 0 if area is too small on populate

[Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>]

W dniu 27.04.2020 o 13:44, Ray Kinsella pisze:
>
> On 25/04/2020 23:23, Thomas Monjalon wrote:
>> From: Olivier Matz <olivier.matz@6wind.com>
>>
>> Change rte_mempool_populate_iova() and rte_mempool_populate_iova() to
... and rte_mempool_populate_virt()
>> return 0 instead of -EINVAL when there is not enough room to store one
>> object, as it can be helpful for applications to distinguish this
>> specific case.
>>
>> As this is an ABI change, use symbol versioning to preserve old
>> behavior for binary applications.
>>
>> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
>> ---
>>
>> changes in v3:
>>      - rebase
>>      - remove deprecation notice
>>      - notify API change in release notes
>>      - fix ABI version from 20.0.1 to 20.0.2 (should be 21 maybe)
> yes, should be v21.
>
>> This v3 cannot be merged because of a false positive ABI check:
>>
>> 2 Removed functions:
>>    'function int rte_mempool_populate_iova(rte_mempool*, char*, rte_iova_t, size_t, rte_mempool_memchunk_free_cb_t*, void*)'    {rte_mempool_populate_iova@@DPDK_20.0}
>>    'function int rte_mempool_populate_virt(rte_mempool*, char*, size_t, size_t, rte_mempool_memchunk_free_cb_t*, void*)'    {rte_mempool_populate_virt@@DPDK_20.0}
> Well it's not really a false positive, as the v20 symbols are now missing.
> See notes on VERSION_SYMBOL.
>
>> ---
>>   doc/guides/rel_notes/deprecation.rst       |  5 --
>>   doc/guides/rel_notes/release_20_05.rst     |  4 ++
>>   examples/ntb/ntb_fwd.c                     |  2 +-
>>   lib/librte_mempool/meson.build             |  2 +
>>   lib/librte_mempool/rte_mempool.c           | 77 ++++++++++++++++++----
>>   lib/librte_mempool/rte_mempool.h           | 14 ++--
>>   lib/librte_mempool/rte_mempool_version.map |  7 ++
>>   7 files changed, 90 insertions(+), 21 deletions(-)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
>> index 1339f54f5f..20aa745b77 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -65,11 +65,6 @@ Deprecation Notices
>>     structure would be made internal (or removed if all dependencies are cleared)
>>     in future releases.
>>   
>> -* mempool: starting from v20.05, the API of rte_mempool_populate_iova()
>> -  and rte_mempool_populate_virt() will change to return 0 instead
>> -  of -EINVAL when there is not enough room to store one object. The ABI
>> -  will be preserved until 20.11.
>> -
>>   * ethdev: the legacy filter API, including
>>     ``rte_eth_dev_filter_supported()``, ``rte_eth_dev_filter_ctrl()`` as well
>>     as filter types MACVLAN, ETHERTYPE, FLEXIBLE, SYN, NTUPLE, TUNNEL, FDIR,
>> diff --git a/doc/guides/rel_notes/release_20_05.rst b/doc/guides/rel_notes/release_20_05.rst
>> index b124c3f287..ab20a7d021 100644
>> --- a/doc/guides/rel_notes/release_20_05.rst
>> +++ b/doc/guides/rel_notes/release_20_05.rst
>> @@ -241,6 +241,10 @@ API Changes
>>      Also, make sure to start the actual text at the margin.
>>      =========================================================
>>   
>> +* mempool: The API of ``rte_mempool_populate_iova()`` and
>> +  ``rte_mempool_populate_virt()`` changed to return 0 instead of -EINVAL
>> +  when there is not enough room to store one object.
>> +
>>   
>>   ABI Changes
>>   -----------
>> diff --git a/examples/ntb/ntb_fwd.c b/examples/ntb/ntb_fwd.c
>> index d49189e175..eba8ebf9fa 100644
>> --- a/examples/ntb/ntb_fwd.c
>> +++ b/examples/ntb/ntb_fwd.c
>> @@ -1319,7 +1319,7 @@ ntb_mbuf_pool_create(uint16_t mbuf_seg_size, uint32_t nb_mbuf,
>>   					mz->len - ntb_info.ntb_hdr_size,
>>   					ntb_mempool_mz_free,
>>   					(void *)(uintptr_t)mz);
>> -		if (ret < 0) {
>> +		if (ret <= 0) {
>>   			rte_memzone_free(mz);
>>   			rte_mempool_free(mp);
>>   			return NULL;
>> diff --git a/lib/librte_mempool/meson.build b/lib/librte_mempool/meson.build
>> index a6e861cbfc..7dbe6b9bea 100644
>> --- a/lib/librte_mempool/meson.build
>> +++ b/lib/librte_mempool/meson.build
>> @@ -9,6 +9,8 @@ foreach flag: extra_flags
>>   	endif
>>   endforeach
>>   
>> +use_function_versioning = true
>> +
>>   sources = files('rte_mempool.c', 'rte_mempool_ops.c',
>>   		'rte_mempool_ops_default.c', 'mempool_trace_points.c')
>>   headers = files('rte_mempool.h', 'rte_mempool_trace.h',
>> diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
>> index 0be8f9f59d..edbdafaafb 100644
>> --- a/lib/librte_mempool/rte_mempool.c
>> +++ b/lib/librte_mempool/rte_mempool.c
>> @@ -31,6 +31,7 @@
>>   #include <rte_string_fns.h>
>>   #include <rte_spinlock.h>
>>   #include <rte_tailq.h>
>> +#include <rte_function_versioning.h>
>>   
>>   #include "rte_mempool.h"
>>   #include "rte_mempool_trace.h"
>> @@ -303,12 +304,17 @@ mempool_ops_alloc_once(struct rte_mempool *mp)
>>   	return 0;
>>   }
>>   
>> +__vsym int
>> +rte_mempool_populate_iova_v20_0_2(struct rte_mempool *mp, char *vaddr,
>> +	rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
>> +	void *opaque);
>> +
>>   /* Add objects in the pool, using a physically contiguous memory
>>    * zone. Return the number of objects added, or a negative value
>>    * on error.
>>    */
>> -static int
>> -__rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>> +__vsym int
>> +rte_mempool_populate_iova_v20_0_2(struct rte_mempool *mp, char *vaddr,
>>   	rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
>>   	void *opaque)
>>   {
>> @@ -366,14 +372,27 @@ __rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>>   	return ret;
>>   }
>>   
>> -int
>> -rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>> +BIND_DEFAULT_SYMBOL(rte_mempool_populate_iova, _v20_0_2, 20.0.2);
> as discussed v21.
>
>> +MAP_STATIC_SYMBOL(
>> +	int rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>> +				rte_iova_t iova, size_t len,
>> +				rte_mempool_memchunk_free_cb_t *free_cb,
>> +				void *opaque),
>> +	rte_mempool_populate_iova_v20_0_2);
>> +
>> +__vsym int
>> +rte_mempool_populate_iova_v20(struct rte_mempool *mp, char *vaddr,
>> +	rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
>> +	void *opaque);
>> +
>> +__vsym int
>> +rte_mempool_populate_iova_v20(struct rte_mempool *mp, char *vaddr,
>>   	rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
>>   	void *opaque)
>>   {
>>   	int ret;
>>   
>> -	ret = __rte_mempool_populate_iova(mp, vaddr, iova, len, free_cb,
>> +	ret = rte_mempool_populate_iova_v20_0_2(mp, vaddr, iova, len, free_cb,
>>   					opaque);
>>   	if (ret == 0)
>>   		ret = -EINVAL;
>> @@ -381,6 +400,7 @@ rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>>   	rte_mempool_trace_populate_iova(mp, vaddr, iova, len, free_cb, opaque);
>>   	return ret;
>>   }
>> +VERSION_SYMBOL(rte_mempool_populate_iova, _v20_0, 20.0);
> this should be
>
> VERSION_SYMBOL(rte_mempool_populate_iova, _v20, 20.0);
>
>>   
>>   static rte_iova_t
>>   get_iova(void *addr)
>> @@ -395,11 +415,16 @@ get_iova(void *addr)
>>   	return ms->iova + RTE_PTR_DIFF(addr, ms->addr);
>>   }
>>   
>> +__vsym int
>> +rte_mempool_populate_virt_v20_0_2(struct rte_mempool *mp, char *addr,
>> +	size_t len, size_t pg_sz, rte_mempool_memchunk_free_cb_t *free_cb,
>> +	void *opaque);
>> +
>>   /* Populate the mempool with a virtual area. Return the number of
>>    * objects added, or a negative value on error.
>>    */
>> -int
>> -rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
>> +__vsym int
>> +rte_mempool_populate_virt_v20_0_2(struct rte_mempool *mp, char *addr,
>>   	size_t len, size_t pg_sz, rte_mempool_memchunk_free_cb_t *free_cb,
>>   	void *opaque)
>>   {
>> @@ -432,7 +457,7 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
>>   				break;
>>   		}
>>   
>> -		ret = __rte_mempool_populate_iova(mp, addr + off, iova,
>> +		ret = rte_mempool_populate_iova_v20_0_2(mp, addr + off, iova,
>>   			phys_len, free_cb, opaque);
>>   		if (ret == 0)
>>   			continue;
>> @@ -443,9 +468,6 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
>>   		cnt += ret;
>>   	}
>>   
>> -	if (cnt == 0)
>> -		return -EINVAL;
>> -
>>   	rte_mempool_trace_populate_virt(mp, addr, len, pg_sz, free_cb, opaque);
>>   	return cnt;
>>   
>> @@ -453,6 +475,35 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
>>   	rte_mempool_free_memchunks(mp);
>>   	return ret;
>>   }
>> +BIND_DEFAULT_SYMBOL(rte_mempool_populate_virt, _v20_0_2, 20.0.2);
> as discussed v21.
>
>> +MAP_STATIC_SYMBOL(
>> +	int rte_mempool_populate_virt(struct rte_mempool *mp,
>> +				char *addr, size_t len, size_t pg_sz,
>> +				rte_mempool_memchunk_free_cb_t *free_cb,
>> +				void *opaque),
>> +	rte_mempool_populate_virt_v20_0_2);
>> +
>> +__vsym int
>> +rte_mempool_populate_virt_v20(struct rte_mempool *mp, char *addr,
>> +	size_t len, size_t pg_sz, rte_mempool_memchunk_free_cb_t *free_cb,
>> +	void *opaque);
>> +
>> +__vsym int
>> +rte_mempool_populate_virt_v20(struct rte_mempool *mp, char *addr,
>> +	size_t len, size_t pg_sz, rte_mempool_memchunk_free_cb_t *free_cb,
>> +	void *opaque)
>> +{
>> +	int ret;
>> +
>> +	ret = rte_mempool_populate_virt_v20_0_2(mp, addr, len, pg_sz,
>> +						free_cb, opaque);
>> +
>> +	if (ret == 0)
>> +		ret = -EINVAL;
>> +
>> +	return ret;
>> +}
>> +VERSION_SYMBOL(rte_mempool_populate_virt, _v20_0, 20.0);
> this should be
> VERSION_SYMBOL(rte_mempool_populate_virt, _v20, 20.0);
>
>
>>   
>>   /* Get the minimal page size used in a mempool before populating it. */
>>   int
>> @@ -609,6 +660,8 @@ rte_mempool_populate_default(struct rte_mempool *mp)
>>   				mz->len, pg_sz,
>>   				rte_mempool_memchunk_mz_free,
>>   				(void *)(uintptr_t)mz);
>> +		if (ret == 0) /* should not happen */
>> +			ret = -ENOBUFS;
>>   		if (ret < 0) {
>>   			rte_memzone_free(mz);
>>   			goto fail;
>> @@ -701,6 +754,8 @@ rte_mempool_populate_anon(struct rte_mempool *mp)
>>   
>>   	ret = rte_mempool_populate_virt(mp, addr, size, getpagesize(),
>>   		rte_mempool_memchunk_anon_free, addr);
>> +	if (ret == 0) /* should not happen */
>> +		ret = -ENOBUFS;
>>   	if (ret < 0) {
>>   		rte_errno = -ret;
>>   		goto fail;
>> diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
>> index 6e0573ea42..652d19f9f1 100644
>> --- a/lib/librte_mempool/rte_mempool.h
>> +++ b/lib/librte_mempool/rte_mempool.h
>> @@ -1112,9 +1112,12 @@ rte_mempool_free(struct rte_mempool *mp);
>>    * @param opaque
>>    *   An opaque argument passed to free_cb.
>>    * @return
>> - *   The number of objects added on success.
>> + *   The number of objects added on success (strictly positive).
>>    *   On error, the chunk is not added in the memory list of the
>> - *   mempool and a negative errno is returned.
>> + *   mempool the following code is returned:
>> + *     (0): not enough room in chunk for one object.
>> + *     (-ENOSPC): mempool is already populated.
>> + *     (-ENOMEM): allocation failure.
>>    */
>>   int rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>>   	rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
>> @@ -1139,9 +1142,12 @@ int rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
>>    * @param opaque
>>    *   An opaque argument passed to free_cb.
>>    * @return
>> - *   The number of objects added on success.
>> + *   The number of objects added on success (strictly positive).
>>    *   On error, the chunk is not added in the memory list of the
>> - *   mempool and a negative errno is returned.
>> + *   mempool the following code is returned:
>> + *     (0): not enough room in chunk for one object.
>> + *     (-ENOSPC): mempool is already populated.
>> + *     (-ENOMEM): allocation failure.
>>    */
>>   int
>>   rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
>> diff --git a/lib/librte_mempool/rte_mempool_version.map b/lib/librte_mempool/rte_mempool_version.map
>> index 695dd6e04f..9e58093665 100644
>> --- a/lib/librte_mempool/rte_mempool_version.map
>> +++ b/lib/librte_mempool/rte_mempool_version.map
>> @@ -31,6 +31,13 @@ DPDK_20.0 {
>>   	local: *;
>>   };
>>   
>> +DPDK_20.0.2 {
> as discussed DPDK_21
>
>> +	global:
>> +
>> +	rte_mempool_populate_iova;
>> +	rte_mempool_populate_virt;
>> +} DPDK_20.0;
>> +
>>   EXPERIMENTAL {
>>   	global:
>>   
>>
-- 

Lukasz Wojciechowski
Principal Software Engineer

Samsung R&D Institute Poland
Samsung Electronics
Office +48 22 377 88 25
l.wojciechow@partner.samsung.com