Hi Andre, Thanks for your help, patch enqueued to 23.11 LTS patch list. Regards, Xueming ________________________________ From: Andre Muezerie Sent: Monday, December 9, 2024 11:56 PM To: stable@dpdk.org Cc: Andre Muezerie Subject: [PATCH 23.11] rcu: fix implicit conversion in bit shift [ upstream commit ffe827f38e6e0be8a307d7ef9c0e1347874f0af7 ] ../lib/rcu/rte_rcu_qsbr.c(101): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?) ../lib/rcu/rte_rcu_qsbr.c(107): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?) ../lib/rcu/rte_rcu_qsbr.c(145): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?) These warnings are being issued by the MSVC compiler. Since the result is being stored in a variable of type uint64_t, it makes sense to shift a 64-bit number instead of shifting a 32-bit number and then having the compiler to convert the result implicitly to 64 bits. UINT64_C was used in the fix as it is the portable way to define a 64-bit constant (ULL suffix is architecture dependent). From reading the code this is also a bugfix: (1 << id), where id = thread_id & 0x3f, was wrong when thread_id > 0x1f. Signed-off-by: Andre Muezerie --- lib/rcu/rte_rcu_qsbr.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/lib/rcu/rte_rcu_qsbr.c b/lib/rcu/rte_rcu_qsbr.c index 41a44be4b9..e46ce7958e 100644 --- a/lib/rcu/rte_rcu_qsbr.c +++ b/lib/rcu/rte_rcu_qsbr.c @@ -104,11 +104,11 @@ rte_rcu_qsbr_thread_register(struct rte_rcu_qsbr *v, unsigned int thread_id) /* Check if the thread is already registered */ old_bmap = rte_atomic_load_explicit(__RTE_QSBR_THRID_ARRAY_ELM(v, i), rte_memory_order_relaxed); - if (old_bmap & 1UL << id) + if (old_bmap & RTE_BIT64(id)) return 0; do { - new_bmap = old_bmap | (1UL << id); + new_bmap = old_bmap | RTE_BIT64(id); success = rte_atomic_compare_exchange_strong_explicit( __RTE_QSBR_THRID_ARRAY_ELM(v, i), &old_bmap, new_bmap, @@ -117,7 +117,7 @@ rte_rcu_qsbr_thread_register(struct rte_rcu_qsbr *v, unsigned int thread_id) if (success) rte_atomic_fetch_add_explicit(&v->num_threads, 1, rte_memory_order_relaxed); - else if (old_bmap & (1UL << id)) + else if (old_bmap & RTE_BIT64(id)) /* Someone else registered this thread. * Counter should not be incremented. */ @@ -156,11 +156,11 @@ rte_rcu_qsbr_thread_unregister(struct rte_rcu_qsbr *v, unsigned int thread_id) /* Check if the thread is already unregistered */ old_bmap = rte_atomic_load_explicit(__RTE_QSBR_THRID_ARRAY_ELM(v, i), rte_memory_order_relaxed); - if (!(old_bmap & (1UL << id))) + if (!(old_bmap & RTE_BIT64(id))) return 0; do { - new_bmap = old_bmap & ~(1UL << id); + new_bmap = old_bmap & ~RTE_BIT64(id); /* Make sure any loads of the shared data structure are * completed before removal of the thread from the list of * reporting threads. @@ -173,7 +173,7 @@ rte_rcu_qsbr_thread_unregister(struct rte_rcu_qsbr *v, unsigned int thread_id) if (success) rte_atomic_fetch_sub_explicit(&v->num_threads, 1, rte_memory_order_relaxed); - else if (!(old_bmap & (1UL << id))) + else if (!(old_bmap & RTE_BIT64(id))) /* Someone else unregistered this thread. * Counter should not be incremented. */ @@ -234,7 +234,7 @@ rte_rcu_qsbr_dump(FILE *f, struct rte_rcu_qsbr *v) t = rte_ctz64(bmap); fprintf(f, "%u ", id + t); - bmap &= ~(1UL << t); + bmap &= ~RTE_BIT64(t); } } @@ -261,7 +261,7 @@ rte_rcu_qsbr_dump(FILE *f, struct rte_rcu_qsbr *v) rte_atomic_load_explicit( &v->qsbr_cnt[id + t].lock_cnt, rte_memory_order_relaxed)); - bmap &= ~(1UL << t); + bmap &= ~RTE_BIT64(t); } } -- 2.47.0.vfs.0.3