diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-31 18:55:05 -0500 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-31 18:55:05 -0500 |
commit | 1347e965f5bcfffe82e56d2903ea4f32babaff4e (patch) | |
tree | 51f75d125089a25feb12b9e2e1e5273a59836e32 | |
parent | ac56b94f8049b4c246cd86257ae6c03c0ac75a13 (diff) | |
parent | d7240b988017521ebf89edfadd42c0942f166850 (diff) |
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
generic-ipi: use per cpu data for single cpu ipi calls
cpumask: convert lib/smp_processor_id to new cpumask ops
signals, debug: fix BUG: using smp_processor_id() in preemptible code in print_fatal_signal()
-rw-r--r-- | kernel/signal.c | 2 | ||||
-rw-r--r-- | kernel/smp.c | 36 | ||||
-rw-r--r-- | lib/smp_processor_id.c | 2 |
3 files changed, 36 insertions, 4 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index e73759783dc8..b6b36768b758 100644 --- a/kernel/signal.c +++ b/kernel/signal.c | |||
@@ -909,7 +909,9 @@ static void print_fatal_signal(struct pt_regs *regs, int signr) | |||
909 | } | 909 | } |
910 | #endif | 910 | #endif |
911 | printk("\n"); | 911 | printk("\n"); |
912 | preempt_disable(); | ||
912 | show_regs(regs); | 913 | show_regs(regs); |
914 | preempt_enable(); | ||
913 | } | 915 | } |
914 | 916 | ||
915 | static int __init setup_print_fatal_signals(char *str) | 917 | static int __init setup_print_fatal_signals(char *str) |
diff --git a/kernel/smp.c b/kernel/smp.c index 5cfa0e5e3e88..bbedbb7efe32 100644 --- a/kernel/smp.c +++ b/kernel/smp.c | |||
@@ -18,6 +18,7 @@ __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_function_lock); | |||
18 | enum { | 18 | enum { |
19 | CSD_FLAG_WAIT = 0x01, | 19 | CSD_FLAG_WAIT = 0x01, |
20 | CSD_FLAG_ALLOC = 0x02, | 20 | CSD_FLAG_ALLOC = 0x02, |
21 | CSD_FLAG_LOCK = 0x04, | ||
21 | }; | 22 | }; |
22 | 23 | ||
23 | struct call_function_data { | 24 | struct call_function_data { |
@@ -186,6 +187,9 @@ void generic_smp_call_function_single_interrupt(void) | |||
186 | if (data_flags & CSD_FLAG_WAIT) { | 187 | if (data_flags & CSD_FLAG_WAIT) { |
187 | smp_wmb(); | 188 | smp_wmb(); |
188 | data->flags &= ~CSD_FLAG_WAIT; | 189 | data->flags &= ~CSD_FLAG_WAIT; |
190 | } else if (data_flags & CSD_FLAG_LOCK) { | ||
191 | smp_wmb(); | ||
192 | data->flags &= ~CSD_FLAG_LOCK; | ||
189 | } else if (data_flags & CSD_FLAG_ALLOC) | 193 | } else if (data_flags & CSD_FLAG_ALLOC) |
190 | kfree(data); | 194 | kfree(data); |
191 | } | 195 | } |
@@ -196,6 +200,8 @@ void generic_smp_call_function_single_interrupt(void) | |||
196 | } | 200 | } |
197 | } | 201 | } |
198 | 202 | ||
203 | static DEFINE_PER_CPU(struct call_single_data, csd_data); | ||
204 | |||
199 | /* | 205 | /* |
200 | * smp_call_function_single - Run a function on a specific CPU | 206 | * smp_call_function_single - Run a function on a specific CPU |
201 | * @func: The function to run. This must be fast and non-blocking. | 207 | * @func: The function to run. This must be fast and non-blocking. |
@@ -224,14 +230,38 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, | |||
224 | func(info); | 230 | func(info); |
225 | local_irq_restore(flags); | 231 | local_irq_restore(flags); |
226 | } else if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { | 232 | } else if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { |
227 | struct call_single_data *data = NULL; | 233 | struct call_single_data *data; |
228 | 234 | ||
229 | if (!wait) { | 235 | if (!wait) { |
236 | /* | ||
237 | * We are calling a function on a single CPU | ||
238 | * and we are not going to wait for it to finish. | ||
239 | * We first try to allocate the data, but if we | ||
240 | * fail, we fall back to use a per cpu data to pass | ||
241 | * the information to that CPU. Since all callers | ||
242 | * of this code will use the same data, we must | ||
243 | * synchronize the callers to prevent a new caller | ||
244 | * from corrupting the data before the callee | ||
245 | * can access it. | ||
246 | * | ||
247 | * The CSD_FLAG_LOCK is used to let us know when | ||
248 | * the IPI handler is done with the data. | ||
249 | * The first caller will set it, and the callee | ||
250 | * will clear it. The next caller must wait for | ||
251 | * it to clear before we set it again. This | ||
252 | * will make sure the callee is done with the | ||
253 | * data before a new caller will use it. | ||
254 | */ | ||
230 | data = kmalloc(sizeof(*data), GFP_ATOMIC); | 255 | data = kmalloc(sizeof(*data), GFP_ATOMIC); |
231 | if (data) | 256 | if (data) |
232 | data->flags = CSD_FLAG_ALLOC; | 257 | data->flags = CSD_FLAG_ALLOC; |
233 | } | 258 | else { |
234 | if (!data) { | 259 | data = &per_cpu(csd_data, me); |
260 | while (data->flags & CSD_FLAG_LOCK) | ||
261 | cpu_relax(); | ||
262 | data->flags = CSD_FLAG_LOCK; | ||
263 | } | ||
264 | } else { | ||
235 | data = &d; | 265 | data = &d; |
236 | data->flags = CSD_FLAG_WAIT; | 266 | data->flags = CSD_FLAG_WAIT; |
237 | } | 267 | } |
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c index 0f8fc22ed103..4689cb073da4 100644 --- a/lib/smp_processor_id.c +++ b/lib/smp_processor_id.c | |||
@@ -22,7 +22,7 @@ notrace unsigned int debug_smp_processor_id(void) | |||
22 | * Kernel threads bound to a single CPU can safely use | 22 | * Kernel threads bound to a single CPU can safely use |
23 | * smp_processor_id(): | 23 | * smp_processor_id(): |
24 | */ | 24 | */ |
25 | if (cpus_equal(current->cpus_allowed, cpumask_of_cpu(this_cpu))) | 25 | if (cpumask_equal(¤t->cpus_allowed, cpumask_of(this_cpu))) |
26 | goto out; | 26 | goto out; |
27 | 27 | ||
28 | /* | 28 | /* |