Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. As a precursor to removing[2] this[3] macro[4], refactor code to avoid its need. The original reason for its use here was to work around the #ifdef being the only place the variable was used. This is better expressed using IS_ENABLED() and a new code block where the variable can be used unconditionally. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/
Unified · Split
| @@ -543,7 +543,6 @@ static void __init numa_clear_kernel_node_hotplug(void) · 542 unmodified lines | ||
| 543 | 543 | |
| 544 | 544 | static int __init numa_register_memblks(struct numa_meminfo *mi) |
| 545 | 545 | { |
| 546 | − unsigned long uninitialized_var(pfn_align); | |
| 547 | 546 | int i, nid; |
| 548 | 547 | |
| 549 | 548 | /* Account for nodes with cpus and no memory */ |
| @@ -571,15 +570,16 @@ static int __init numa_register_memblks(struct numa_meminfo *mi) · 21 unmodified lines | ||
| 571 | 570 | * If sections array is gonna be used for pfn -> nid mapping, check |
| 572 | 571 | * whether its granularity is fine enough. |
| 573 | 572 | */ |
| 574 | −#ifdef NODE_NOT_IN_PAGE_FLAGS | |
| 575 | − pfn_align = node_map_pfn_alignment(); | |
| 576 | − if (pfn_align && pfn_align < PAGES_PER_SECTION) { | |
| 577 | − printk(KERN_WARNING "Node alignment %LuMB < min %LuMB, rejecting NUMA config\n", | |
| 578 | − PFN_PHYS(pfn_align) >> 20, | |
| 579 | − PFN_PHYS(PAGES_PER_SECTION) >> 20); | |
| 580 | − return -EINVAL; | |
| 573 | + if (IS_ENABLED(NODE_NOT_IN_PAGE_FLAGS)) { | |
| 574 | + unsigned long pfn_align = node_map_pfn_alignment(); | |
| 575 | + | |
| 576 | + if (pfn_align && pfn_align < PAGES_PER_SECTION) { | |
| 577 | + pr_warn("Node alignment %LuMB < min %LuMB, rejecting NUMA config\n", | |
| 578 | + PFN_PHYS(pfn_align) >> 20, | |
| 579 | + PFN_PHYS(PAGES_PER_SECTION) >> 20); | |
| 580 | + return -EINVAL; | |
| 581 | + } | |
| 581 | 582 | } |
| 582 | −#endif | |
| 583 | 583 | if (!numa_meminfo_cover_memory(mi)) |
| 584 | 584 | return -EINVAL; |
| 585 | 585 | |
| @@ -98,9 +98,11 @@ · 97 unmodified lines | ||
| 98 | 98 | /* |
| 99 | 99 | * We are going to use the flags for the page to node mapping if its in |
| 100 | 100 | * there. This includes the case where there is no node, so it is implicit. |
| 101 | + * Note that this #define MUST have a value so that it can be tested with | |
| 102 | + * the IS_ENABLED() macro. | |
| 101 | 103 | */ |
| 102 | 104 | #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0) |
| 103 | −#define NODE_NOT_IN_PAGE_FLAGS | |
| 105 | +#define NODE_NOT_IN_PAGE_FLAGS 1 | |
| 104 | 106 | #endif |
| 105 | 107 | |
| 106 | 108 | #if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0 |