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authorLi Zefan <lizf@cn.fujitsu.com>2009-07-07 07:52:52 +0200
committerIngo Molnar <mingo@elte.hu>2009-07-10 11:59:40 +0200
commitbe9742e6cb107fe1d77db7a081ea4eb25e79e1ad (patch)
tree02730de2546677700ba98944b755c1bfbeee27ed /kernel/trace
parentksym_tracer: Extract trace entry from struct trace_ksym (diff)
downloadlinux-be9742e6cb107fe1d77db7a081ea4eb25e79e1ad.tar.xz
linux-be9742e6cb107fe1d77db7a081ea4eb25e79e1ad.zip
ksym_tracer: Rewrite ksym_trace_filter_read()
Reading ksym_trace_filter gave me some arbitrary characters, when it should show nothing. It's because buf is not initialized when there's no filter. Also reduce stack usage by about 512 bytes. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: "K.Prasad" <prasad@linux.vnet.ibm.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A52E2B4.6030706@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_ksym.c29
1 files changed, 18 insertions, 11 deletions
diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index 085ff055fdfa..b6710d31bdf0 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -35,7 +35,6 @@
#define KSYM_TRACER_MAX HBP_NUM
#define KSYM_TRACER_OP_LEN 3 /* rw- */
-#define KSYM_FILTER_ENTRY_LEN (KSYM_NAME_LEN + KSYM_TRACER_OP_LEN + 1)
struct trace_ksym {
struct hw_breakpoint *ksym_hbp;
@@ -230,25 +229,33 @@ static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
{
struct trace_ksym *entry;
struct hlist_node *node;
- char buf[KSYM_FILTER_ENTRY_LEN * KSYM_TRACER_MAX];
- ssize_t ret, cnt = 0;
+ struct trace_seq *s;
+ ssize_t cnt = 0;
+ int ret;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+ trace_seq_init(s);
mutex_lock(&ksym_tracer_mutex);
hlist_for_each_entry(entry, node, &ksym_filter_head, ksym_hlist) {
- cnt += snprintf(&buf[cnt], KSYM_FILTER_ENTRY_LEN - cnt, "%s:",
- entry->ksym_hbp->info.name);
+ ret = trace_seq_printf(s, "%s:", entry->ksym_hbp->info.name);
if (entry->ksym_hbp->info.type == HW_BREAKPOINT_WRITE)
- cnt += snprintf(&buf[cnt], KSYM_FILTER_ENTRY_LEN - cnt,
- "-w-\n");
+ ret = trace_seq_puts(s, "-w-\n");
else if (entry->ksym_hbp->info.type == HW_BREAKPOINT_RW)
- cnt += snprintf(&buf[cnt], KSYM_FILTER_ENTRY_LEN - cnt,
- "rw-\n");
+ ret = trace_seq_puts(s, "rw-\n");
+ WARN_ON_ONCE(!ret);
}
- ret = simple_read_from_buffer(ubuf, count, ppos, buf, strlen(buf));
+
+ cnt = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
+
mutex_unlock(&ksym_tracer_mutex);
- return ret;
+ kfree(s);
+
+ return cnt;
}
static ssize_t ksym_trace_filter_write(struct file *file,