linux-kernel - [PATCH] kdb: avoid on-stack cpumask, old-style accessors

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Message-Id: <201010272030.34310.rusty@rustcorp.com.au>
Date:	Wed, 27 Oct 2010 20:30:34 +1030
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Jason Wessel <jason.wessel@...driver.com>
Cc:	linux-kernel@...r.kernel.org, kgdb-bugreport@...ts.sourceforge.net
Subject: [PATCH] kdb: avoid on-stack cpumask, old-style accessors

That's quite a big stack already; I assume moving it to a static bitmap
is OK for this usage (a cpumask_var_t might require kmalloc, not sure
that's a good idea here).

Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Cc: kgdb-bugreport@...ts.sourceforge.net
Cc: Jason Wessel <jason.wessel@...driver.com>
---
 kernel/debug/kdb/kdb_main.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2598,6 +2598,9 @@ static int kdb_summary(int argc, const c
 	return 0;
 }
 
+/* Not sure when to initialize this, so make it a static bitmap. */
+static DECLARE_BITMAP(per_cpu_suppress, NR_CPUS);
+
 /*
  * kdb_per_cpu - This function implements the 'per_cpu' command.
  */
@@ -2605,7 +2608,7 @@ static int kdb_per_cpu(int argc, const c
 {
 	char buf[256], fmtstr[64];
 	kdb_symtab_t symtab;
-	cpumask_t suppress = CPU_MASK_NONE;
+	struct cpumask *suppress = to_cpumask(per_cpu_suppress);
 	int cpu, diag;
 	unsigned long addr, val, bytesperword = 0, whichcpu = ~0UL;
 
@@ -2649,7 +2652,7 @@ static int kdb_per_cpu(int argc, const c
 #define KDB_PCU(cpu) 0
 #endif
 #endif
-
+	cpumask_clear(suppress);
 	for_each_online_cpu(cpu) {
 		if (whichcpu != ~0UL && whichcpu != cpu)
 			continue;
@@ -2662,7 +2665,7 @@ static int kdb_per_cpu(int argc, const c
 		}
 #ifdef	CONFIG_SMP
 		if (!val) {
-			cpu_set(cpu, suppress);
+			cpumask_set_cpu(cpu, suppress);
 			continue;
 		}
 #endif	/* CONFIG_SMP */
@@ -2671,17 +2674,16 @@ static int kdb_per_cpu(int argc, const c
 			bytesperword == KDB_WORD_SIZE,
 			1, bytesperword, 1, 1, 0);
 	}
-	if (cpus_weight(suppress) == 0)
+	if (cpumask_weight(suppress) == 0)
 		return 0;
 	kdb_printf("Zero suppressed cpu(s):");
-	for (cpu = first_cpu(suppress); cpu < num_possible_cpus();
-	     cpu = next_cpu(cpu, suppress)) {
+	for_each_cpu(cpu, suppress) {
 		kdb_printf(" %d", cpu);
-		if (cpu == num_possible_cpus() - 1 ||
-		    next_cpu(cpu, suppress) != cpu + 1)
+		if (cpu == nr_cpu_ids - 1 ||
+		    cpumask_next(cpu, suppress) != cpu + 1)
 			continue;
-		while (cpu < num_possible_cpus() &&
-		       next_cpu(cpu, suppress) == cpu + 1)
+		while (cpu < nr_cpu_ids &&
+		       cpumask_next(cpu, suppress) == cpu + 1)
 			++cpu;
 		kdb_printf("-%d", cpu);
 	}
--
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