diff options
Diffstat (limited to 'kernel/trace/pid_list.c')
| -rw-r--r-- | kernel/trace/pid_list.c | 45 |
1 files changed, 27 insertions, 18 deletions
diff --git a/kernel/trace/pid_list.c b/kernel/trace/pid_list.c index 95106d02b32d..dbee72d69d0a 100644 --- a/kernel/trace/pid_list.c +++ b/kernel/trace/pid_list.c @@ -3,6 +3,7 @@ * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org> */ #include <linux/spinlock.h> +#include <linux/seqlock.h> #include <linux/irq_work.h> #include <linux/slab.h> #include "trace.h" @@ -81,13 +82,9 @@ static inline bool upper_empty(union upper_chunk *chunk) { /* * If chunk->data has no lower chunks, it will be the same - * as a zeroed bitmask. Use find_first_bit() to test it - * and if it doesn't find any bits set, then the array - * is empty. + * as a zeroed bitmask. */ - int bit = find_first_bit((unsigned long *)chunk->data, - sizeof(chunk->data) * 8); - return bit >= sizeof(chunk->data) * 8; + return bitmap_empty((unsigned long *)chunk->data, BITS_PER_TYPE(chunk->data)); } static inline int pid_split(unsigned int pid, unsigned int *upper1, @@ -130,7 +127,7 @@ bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid) { union upper_chunk *upper_chunk; union lower_chunk *lower_chunk; - unsigned long flags; + unsigned int seq; unsigned int upper1; unsigned int upper2; unsigned int lower; @@ -142,14 +139,16 @@ bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid) if (pid_split(pid, &upper1, &upper2, &lower) < 0) return false; - raw_spin_lock_irqsave(&pid_list->lock, flags); - upper_chunk = pid_list->upper[upper1]; - if (upper_chunk) { - lower_chunk = upper_chunk->data[upper2]; - if (lower_chunk) - ret = test_bit(lower, lower_chunk->data); - } - raw_spin_unlock_irqrestore(&pid_list->lock, flags); + do { + seq = read_seqcount_begin(&pid_list->seqcount); + ret = false; + upper_chunk = pid_list->upper[upper1]; + if (upper_chunk) { + lower_chunk = upper_chunk->data[upper2]; + if (lower_chunk) + ret = test_bit(lower, lower_chunk->data); + } + } while (read_seqcount_retry(&pid_list->seqcount, seq)); return ret; } @@ -182,6 +181,7 @@ int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid) return -EINVAL; raw_spin_lock_irqsave(&pid_list->lock, flags); + write_seqcount_begin(&pid_list->seqcount); upper_chunk = pid_list->upper[upper1]; if (!upper_chunk) { upper_chunk = get_upper_chunk(pid_list); @@ -203,6 +203,7 @@ int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid) set_bit(lower, lower_chunk->data); ret = 0; out: + write_seqcount_end(&pid_list->seqcount); raw_spin_unlock_irqrestore(&pid_list->lock, flags); return ret; } @@ -234,6 +235,7 @@ int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid) return -EINVAL; raw_spin_lock_irqsave(&pid_list->lock, flags); + write_seqcount_begin(&pid_list->seqcount); upper_chunk = pid_list->upper[upper1]; if (!upper_chunk) goto out; @@ -254,6 +256,7 @@ int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid) } } out: + write_seqcount_end(&pid_list->seqcount); raw_spin_unlock_irqrestore(&pid_list->lock, flags); return 0; } @@ -344,8 +347,10 @@ static void pid_list_refill_irq(struct irq_work *iwork) again: raw_spin_lock(&pid_list->lock); + write_seqcount_begin(&pid_list->seqcount); upper_count = CHUNK_ALLOC - pid_list->free_upper_chunks; lower_count = CHUNK_ALLOC - pid_list->free_lower_chunks; + write_seqcount_end(&pid_list->seqcount); raw_spin_unlock(&pid_list->lock); if (upper_count <= 0 && lower_count <= 0) @@ -354,7 +359,7 @@ static void pid_list_refill_irq(struct irq_work *iwork) while (upper_count-- > 0) { union upper_chunk *chunk; - chunk = kzalloc(sizeof(*chunk), GFP_KERNEL); + chunk = kzalloc(sizeof(*chunk), GFP_NOWAIT); if (!chunk) break; *upper_next = chunk; @@ -365,7 +370,7 @@ static void pid_list_refill_irq(struct irq_work *iwork) while (lower_count-- > 0) { union lower_chunk *chunk; - chunk = kzalloc(sizeof(*chunk), GFP_KERNEL); + chunk = kzalloc(sizeof(*chunk), GFP_NOWAIT); if (!chunk) break; *lower_next = chunk; @@ -374,6 +379,7 @@ static void pid_list_refill_irq(struct irq_work *iwork) } raw_spin_lock(&pid_list->lock); + write_seqcount_begin(&pid_list->seqcount); if (upper) { *upper_next = pid_list->upper_list; pid_list->upper_list = upper; @@ -384,6 +390,7 @@ static void pid_list_refill_irq(struct irq_work *iwork) pid_list->lower_list = lower; pid_list->free_lower_chunks += lcnt; } + write_seqcount_end(&pid_list->seqcount); raw_spin_unlock(&pid_list->lock); /* @@ -414,7 +421,7 @@ struct trace_pid_list *trace_pid_list_alloc(void) int i; /* According to linux/thread.h, pids can be no bigger that 30 bits */ - WARN_ON_ONCE(pid_max > (1 << 30)); + WARN_ON_ONCE(init_pid_ns.pid_max > (1 << 30)); pid_list = kzalloc(sizeof(*pid_list), GFP_KERNEL); if (!pid_list) @@ -423,6 +430,7 @@ struct trace_pid_list *trace_pid_list_alloc(void) init_irq_work(&pid_list->refill_irqwork, pid_list_refill_irq); raw_spin_lock_init(&pid_list->lock); + seqcount_raw_spinlock_init(&pid_list->seqcount, &pid_list->lock); for (i = 0; i < CHUNK_ALLOC; i++) { union upper_chunk *chunk; @@ -451,6 +459,7 @@ struct trace_pid_list *trace_pid_list_alloc(void) /** * trace_pid_list_free - Frees an allocated pid_list. + * @pid_list: The pid list to free. * * Frees the memory for a pid_list that was allocated. */ |