Re: [PATCH v2 4/5] blk-iocost: fix sleeping in atomic context warnning

Yu Kuai
2022-11-17T11:29:02Z

Hi, Tejun!

在 2022/11/15 6:07, Tejun Heo 写道:

>
> Any chance I can persuade you into updating match_NUMBER() helpers to not
> use match_strdup()? They can easily disable irq/preemption and use percpu
> buffers and we won't need most of this patchset.

Does the following patch match your proposal?

diff --git a/lib/parser.c b/lib/parser.c
index bcb23484100e..ded652471919 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -11,6 +11,24 @@
#include <linux/slab.h>
#include <linux/string.h>

+#define U64_MAX_SIZE 20
+
+static DEFINE_PER_CPU(char, buffer[U64_MAX_SIZE]);
+
+static char *get_buffer(void)
+{
+ preempt_disable();
+ local_irq_disable();
+
+ return this_cpu_ptr(buffer);
+}
+
+static void put_buffer(void)
+{
+ local_irq_enable();
+ preempt_enable();
+}
+

Then match_strdup() and kfree() in match_NUMBER() can be replaced with
get_buffer() and put_buffer().

Thanks,
Kuai
>
> Thanks.
>