| 1 | #ifndef _LTTNG_WRAPPER_WRITEBACK_H |
| 2 | #define _LTTNG_WRAPPER_WRITEBACK_H |
| 3 | |
| 4 | /* |
| 5 | * wrapper/writeback.h |
| 6 | * |
| 7 | * wrapper around global_dirty_limit read. Using KALLSYMS with KALLSYMS_ALL |
| 8 | * to get its address when available, else we need to have a kernel that |
| 9 | * exports this variable to GPL modules. |
| 10 | * |
| 11 | * Copyright (C) 2013 Mentor Graphics Corp. |
| 12 | * |
| 13 | * This library is free software; you can redistribute it and/or |
| 14 | * modify it under the terms of the GNU Lesser General Public |
| 15 | * License as published by the Free Software Foundation; only |
| 16 | * version 2.1 of the License. |
| 17 | * |
| 18 | * This library is distributed in the hope that it will be useful, |
| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 21 | * Lesser General Public License for more details. |
| 22 | * |
| 23 | * You should have received a copy of the GNU Lesser General Public |
| 24 | * License along with this library; if not, write to the Free Software |
| 25 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 26 | */ |
| 27 | |
| 28 | #include <lttng-kernel-version.h> |
| 29 | |
| 30 | #ifdef CONFIG_KALLSYMS_ALL |
| 31 | #include <linux/kallsyms.h> |
| 32 | #include <wrapper/kallsyms.h> |
| 33 | |
| 34 | |
| 35 | |
| 36 | #if LINUX_VERSION_CODE >= KERNEL_VERSION(4,2,0) |
| 37 | |
| 38 | static struct wb_domain *global_wb_domain_sym; |
| 39 | |
| 40 | static inline |
| 41 | unsigned long wrapper_global_dirty_limit(void) |
| 42 | { |
| 43 | if (!global_wb_domain_sym) |
| 44 | global_wb_domain_sym = |
| 45 | (void *) kallsyms_lookup_dataptr("global_wb_domain"); |
| 46 | if (global_wb_domain_sym) { |
| 47 | return global_wb_domain_sym->dirty_limit; |
| 48 | } else { |
| 49 | printk_once(KERN_WARNING "LTTng: global_wb_domain symbol lookup failed.\n"); |
| 50 | return 0; |
| 51 | } |
| 52 | } |
| 53 | #else |
| 54 | |
| 55 | static unsigned long *global_dirty_limit_sym; |
| 56 | |
| 57 | static inline |
| 58 | unsigned long wrapper_global_dirty_limit(void) |
| 59 | { |
| 60 | if (!global_dirty_limit_sym) |
| 61 | global_dirty_limit_sym = |
| 62 | (void *) kallsyms_lookup_dataptr("global_dirty_limit"); |
| 63 | if (global_dirty_limit_sym) { |
| 64 | return *global_dirty_limit_sym; |
| 65 | } else { |
| 66 | printk_once(KERN_WARNING "LTTng: global_dirty_limit symbol lookup failed.\n"); |
| 67 | return 0; |
| 68 | } |
| 69 | } |
| 70 | #endif |
| 71 | |
| 72 | #else /* CONFIG_KALLSYMS_ALL */ |
| 73 | |
| 74 | #include <linux/writeback.h> |
| 75 | |
| 76 | static inline |
| 77 | unsigned long wrapper_global_dirty_limit(void) |
| 78 | { |
| 79 | return global_dirty_limit; |
| 80 | } |
| 81 | |
| 82 | #endif |
| 83 | |
| 84 | #endif /* _LTTNG_WRAPPER_WRITEBACK_H */ |