For each mbuf byte, free_space[i] == 0 means the space is occupied,
free_space[i] != 0 means space is free.
Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
Cc: stable@dpdk.org
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
The value free_space[i] is used to save the size of biggest aligned
element that can fit in the zone, current implementation has one flaw,
for example, if user registers dynfield1 (size = 4, align = 4, req = 124)
first, the free_space would be as below after registration:
0070: 08 08 08 08 08 08 08 08
0078: 08 08 08 08 00 00 00 00
Then if user continues to register dynfield2 (size = 4, align = 4),
free_space would become:
0070: 00 00 00 00 04 04 04 04
0078: 04 04 04 04 00 00 00 00
Further request dynfield3 (size = 8, align = 8) would fail to register
due to alignment requirement can't be satisfied, though there is enough
space remained in mbuf.
This patch fixes above issue by saving alignment only in aligned zone,
after the fix, above registrations order can be satisfied, free_space
would be like:
After dynfield1 registration:
0070: 08 08 08 08 08 08 08 08
0078: 04 04 04 04 00 00 00 00
After dynfield2 registration:
0070: 08 08 08 08 08 08 08 08
0078: 00 00 00 00 00 00 00 00
After dynfield3 registration:
0070: 00 00 00 00 00 00 00 00
0078: 00 00 00 00 00 00 00 00
This patch also reduces iterations in process_score() by jumping align
steps in each loop.
Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
Cc: stable@dpdk.org
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Set rte_errno as ENOMEM when allocation failure.
Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
Cc: stable@dpdk.org
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
We should make sure off + size < sizeof(struct rte_mbuf) to avoid
possible out-of-bounds access of free_space array, there is no issue
currently due to the low bits of free_flags (which is adjacent to
free_space) are always set to 0. But we shouldn't rely on it since it's
fragile and layout of struct mbuf_dyn_shm may be changed in the future.
This patch adds boundary check explicitly to avoid potential risk of
out-of-bounds access.
Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
Cc: stable@dpdk.org
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
TAILQ_ENTRY next is not needed in struct mbuf_dynfield_elt and
mbuf_dynflag_elt, since they are actually chained by rte_tailq_entry's
next field when calling TAILQ_INSERT_TAIL(mbuf_dynfield/dynflag_list, te,
next).
Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
Cc: stable@dpdk.org
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Many features require to store data inside the mbuf. As the room in mbuf
structure is limited, it is not possible to have a field for each
feature. Also, changing fields in the mbuf structure can break the API
or ABI.
This commit addresses these issues, by enabling the dynamic registration
of fields or flags:
- a dynamic field is a named area in the rte_mbuf structure, with a
given size (>= 1 byte) and alignment constraint.
- a dynamic flag is a named bit in the rte_mbuf structure.
The typical use case is a PMD that registers space for an offload
feature, when the application requests to enable this feature. As
the space in mbuf is limited, the space should only be reserved if it
is going to be used (i.e when the application explicitly asks for it).
The registration can be done at any moment, but it is not possible
to unregister fields or flags.
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
