tools: remove unnecessary calls to bpf_probe_read

Most of these calls have been rendered useless by a9f96c0 ("Recognize context member dereferences despite array accesses (iovisor#1828)").
yingtaojuzi · Jul 1, 2018 · 8d78edd · 8d78edd
1 parent 44c28bf
commit 8d78edd
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Showing 4 changed files with 13 additions and 27 deletions.
diff --git a/tools/runqlat.py b/tools/runqlat.py
@@ -168,11 +168,9 @@
  struct task_struct *prev = (struct task_struct *)ctx->args[1];
  struct task_struct *next = (struct task_struct *)ctx->args[2];
  u32 pid, tgid;
- long state;
 
  // ivcsw: treat like an enqueue event and store timestamp
- bpf_probe_read(&state, sizeof(long), &prev->state);
- if (state == TASK_RUNNING) {
+ if (prev->state == TASK_RUNNING) {
  tgid = prev->tgid;
  pid = prev->pid;
  if (!(FILTER || pid == 0)) {

diff --git a/tools/runqslower.py b/tools/runqslower.py
@@ -145,11 +145,7 @@
 {
  // TP_PROTO(struct task_struct *p)
  struct task_struct *p = (struct task_struct *)ctx->args[0];
- u32 tgid, pid;
-
- bpf_probe_read(&tgid, sizeof(tgid), &p->tgid);
- bpf_probe_read(&pid, sizeof(pid), &p->pid);
- return trace_enqueue(tgid, pid);
+ return trace_enqueue(p->tgid, p->pid);
 }
 
 RAW_TRACEPOINT_PROBE(sched_wakeup_new)

diff --git a/tools/tcpaccept.py b/tools/tcpaccept.py
@@ -107,16 +107,16 @@
  if (sk_lingertime_offset - gso_max_segs_offset == 4) 
  // 4.10+ with little endian
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-  bpf_probe_read(&protocol, 1, (void *)((u64)&newsk->sk_gso_max_segs) - 3);
+ protocol = *(u8 *)((u64)&newsk->sk_gso_max_segs - 3);
  else
  // pre-4.10 with little endian
-  bpf_probe_read(&protocol, 1, (void *)((u64)&newsk->sk_wmem_queued) - 3);
+ protocol = *(u8 *)((u64)&newsk->sk_wmem_queued - 3);
 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
  // 4.10+ with big endian
-  bpf_probe_read(&protocol, 1, (void *)((u64)&newsk->sk_gso_max_segs) - 1);
+ protocol = *(u8 *)((u64)&newsk->sk_gso_max_segs - 1);
  else
  // pre-4.10 with big endian
-  bpf_probe_read(&protocol, 1, (void *)((u64)&newsk->sk_wmem_queued) - 1);
+ protocol = *(u8 *)((u64)&newsk->sk_wmem_queued - 1);
 #else
 # error "Fix your compiler's __BYTE_ORDER__?!"
 #endif

diff --git a/tools/tcptracer.py b/tools/tcptracer.py
@@ -116,8 +116,7 @@
  u16 sport = sockp->inet_sport;
  u16 dport = skp->__sk_common.skc_dport;
 #ifdef CONFIG_NET_NS
- possible_net_t skc_net = skp->__sk_common.skc_net;
- bpf_probe_read(&net_ns_inum, sizeof(net_ns_inum), &skc_net.net->ns.inum);
+ net_ns_inum = skp->__sk_common.skc_net.net->ns.inum;
 #endif
 
  ##FILTER_NETNS##
@@ -144,8 +143,7 @@
  u16 sport = sockp->inet_sport;
  u16 dport = skp->__sk_common.skc_dport;
 #ifdef CONFIG_NET_NS
- possible_net_t skc_net = skp->__sk_common.skc_net;
- bpf_probe_read(&net_ns_inum, sizeof(net_ns_inum), &skc_net.net->ns.inum);
+ net_ns_inum = skp->__sk_common.skc_net.net->ns.inum;
 #endif
  bpf_probe_read(&saddr, sizeof(saddr),
  skp->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32);
@@ -430,16 +428,12 @@
  u32 net_ns_inum = 0;
  u8 ipver = 0;
 
- bpf_probe_read(&dport, sizeof(dport), &newsk->__sk_common.skc_dport);
- bpf_probe_read(&lport, sizeof(lport), &newsk->__sk_common.skc_num);
+ dport = newsk->__sk_common.skc_dport;
+ lport = newsk->__sk_common.skc_num;
 
  // Get network namespace id, if kernel supports it
 #ifdef CONFIG_NET_NS
- possible_net_t skc_net = { };
- bpf_probe_read(&skc_net, sizeof(skc_net), &newsk->__sk_common.skc_net);
- bpf_probe_read(&net_ns_inum, sizeof(net_ns_inum), &skc_net.net->ns.inum);
-#else
- net_ns_inum = 0;
+ net_ns_inum = newsk->__sk_common.skc_net.net->ns.inum;
 #endif
 
  ##FILTER_NETNS##
@@ -455,10 +449,8 @@
  evt4.pid = pid >> 32;
  evt4.ip = ipver;
 
- bpf_probe_read(&evt4.saddr, sizeof(evt4.saddr),
- &newsk->__sk_common.skc_rcv_saddr);
- bpf_probe_read(&evt4.daddr, sizeof(evt4.daddr),
- &newsk->__sk_common.skc_daddr);
+ evt4.saddr = newsk->__sk_common.skc_rcv_saddr;
+ evt4.daddr = newsk->__sk_common.skc_daddr;
 
  evt4.sport = lport;
  evt4.dport = ntohs(dport);