[v5,39/39] ip_frag: use C11 alignas

Message ID 1708715054-22386-40-git-send-email-roretzla@linux.microsoft.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Series use C11 alignas |


Context Check Description
ci/checkpatch success coding style OK
ci/loongarch-compilation success Compilation OK
ci/loongarch-unit-testing success Unit Testing PASS
ci/Intel-compilation success Compilation OK
ci/intel-Testing success Testing PASS
ci/intel-Functional success Functional PASS
ci/github-robot: build success github build: passed
ci/iol-mellanox-Performance success Performance Testing PASS
ci/iol-abi-testing success Testing PASS
ci/iol-intel-Performance success Performance Testing PASS
ci/iol-intel-Functional success Functional Testing PASS
ci/iol-compile-amd64-testing success Testing PASS
ci/iol-unit-amd64-testing success Testing PASS
ci/iol-unit-arm64-testing success Testing PASS
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ci/iol-sample-apps-testing success Testing PASS
ci/iol-broadcom-Functional success Functional Testing PASS

Commit Message

Tyler Retzlaff Feb. 23, 2024, 7:04 p.m. UTC
  The current location used for __rte_aligned(a) for alignment of types
and variables is not compatible with MSVC. There is only a single
location accepted by both toolchains.

For variables standard C11 offers alignas(a) supported by conformant
compilers i.e. both MSVC and GCC.

For types the standard offers no alignment facility that compatibly
interoperates with C and C++ but may be achieved by relocating the
placement of __rte_aligned(a) to the aforementioned location accepted
by all currently supported toolchains.

To allow alignment for both compilers do the following:

* Move __rte_aligned from the end of {struct,union} definitions to
  be between {struct,union} and tag.

  The placement between {struct,union} and the tag allows the desired
  alignment to be imparted on the type regardless of the toolchain being
  used for all of GCC, LLVM, MSVC compilers building both C and C++.

* Replace use of __rte_aligned(a) on variables/fields with alignas(a).

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
 lib/ip_frag/ip_reassembly.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)


diff --git a/lib/ip_frag/ip_reassembly.h b/lib/ip_frag/ip_reassembly.h
index a9f97ae..5443c73 100644
--- a/lib/ip_frag/ip_reassembly.h
+++ b/lib/ip_frag/ip_reassembly.h
@@ -47,7 +47,7 @@  struct ip_frag_key {
  * Fragmented packet to reassemble.
  * First two entries in the frags[] array are for the last and first fragments.
-struct ip_frag_pkt {
+struct __rte_cache_aligned ip_frag_pkt {
 	RTE_TAILQ_ENTRY(ip_frag_pkt) lru;      /* LRU list */
 	struct ip_frag_key key;                /* fragmentation key */
 	uint64_t start;                        /* creation timestamp */
@@ -55,20 +55,20 @@  struct ip_frag_pkt {
 	uint32_t frag_size;                    /* size of fragments received */
 	uint32_t last_idx;                     /* index of next entry to fill */
 	struct ip_frag frags[IP_MAX_FRAG_NUM]; /* fragments */
-} __rte_cache_aligned;
  /* fragments tailq */
 RTE_TAILQ_HEAD(ip_pkt_list, ip_frag_pkt);
 /* fragmentation table statistics */
-struct ip_frag_tbl_stat {
+struct __rte_cache_aligned ip_frag_tbl_stat {
 	uint64_t find_num;     /* total # of find/insert attempts. */
 	uint64_t add_num;      /* # of add ops. */
 	uint64_t del_num;      /* # of del ops. */
 	uint64_t reuse_num;    /* # of reuse (del/add) ops. */
 	uint64_t fail_total;   /* total # of add failures. */
 	uint64_t fail_nospace; /* # of 'no space' add failures. */
-} __rte_cache_aligned;
 /* fragmentation table */
 struct rte_ip_frag_tbl {