add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/md/dm-stats.c
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@@ -56,7 +56,7 @@
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 	size_t percpu_alloc_size;
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 	size_t histogram_alloc_size;
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 	struct dm_stat_percpu *stat_percpu[NR_CPUS];
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-	struct dm_stat_shared stat_shared[0];
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+	struct dm_stat_shared stat_shared[];
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 };
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 #define STAT_PRECISE_TIMESTAMPS		1
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@@ -85,7 +85,7 @@
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 	a = shared_memory_amount + alloc_size;
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 	if (a < shared_memory_amount)
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 		return false;
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-	if (a >> PAGE_SHIFT > totalram_pages / DM_STATS_MEMORY_FACTOR)
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+	if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
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 		return false;
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 #ifdef CONFIG_MMU
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 	if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
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@@ -188,7 +188,7 @@
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 	       atomic_read(&shared->in_flight[WRITE]);
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 }
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-void dm_stats_init(struct dm_stats *stats)
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+int dm_stats_init(struct dm_stats *stats)
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 {
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 	int cpu;
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 	struct dm_stats_last_position *last;
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@@ -196,11 +196,16 @@
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 	mutex_init(&stats->mutex);
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 	INIT_LIST_HEAD(&stats->list);
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 	stats->last = alloc_percpu(struct dm_stats_last_position);
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+	if (!stats->last)
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+		return -ENOMEM;
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+
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 	for_each_possible_cpu(cpu) {
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 		last = per_cpu_ptr(stats->last, cpu);
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 		last->last_sector = (sector_t)ULLONG_MAX;
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 		last->last_rw = UINT_MAX;
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 	}
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+
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+	return 0;
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 }
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 void dm_stats_cleanup(struct dm_stats *stats)
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@@ -224,6 +229,7 @@
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 				       atomic_read(&shared->in_flight[READ]),
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 				       atomic_read(&shared->in_flight[WRITE]));
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 			}
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+			cond_resched();
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 		}
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 		dm_stat_free(&s->rcu_head);
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 	}
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@@ -262,7 +268,7 @@
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 	if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
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 		return -EOVERFLOW;
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-	shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
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+	shared_alloc_size = struct_size(s, stat_shared, n_entries);
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 	if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
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 		return -EOVERFLOW;
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@@ -313,6 +319,7 @@
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 	for (ni = 0; ni < n_entries; ni++) {
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 		atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
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 		atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
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+		cond_resched();
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 	}
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 	if (s->n_histogram_entries) {
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@@ -325,6 +332,7 @@
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 		for (ni = 0; ni < n_entries; ni++) {
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 			s->stat_shared[ni].tmp.histogram = hi;
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 			hi += s->n_histogram_entries + 1;
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+			cond_resched();
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 		}
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 	}
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@@ -345,6 +353,7 @@
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 			for (ni = 0; ni < n_entries; ni++) {
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 				p[ni].histogram = hi;
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 				hi += s->n_histogram_entries + 1;
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+				cond_resched();
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 			}
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 		}
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 	}
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@@ -474,6 +483,7 @@
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 			}
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 			DMEMIT("\n");
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 		}
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+		cond_resched();
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 	}
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 	mutex_unlock(&stats->mutex);
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@@ -750,6 +760,7 @@
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 				local_irq_enable();
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 			}
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 		}
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+		cond_resched();
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 	}
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 }
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@@ -865,6 +876,8 @@
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 		if (unlikely(sz + 1 >= maxlen))
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 			goto buffer_overflow;
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+
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+		cond_resched();
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 	}
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 	if (clear)