libbpf-tools: Fix dropped request->rq_disk for kernel 5.17+

githubTang-T · Apr 27, 2022 · 7231ddb · 7231ddb
1 parent 28f2af9
commit 7231ddb
Show file tree

Hide file tree

Showing 4 changed files with 51 additions and 5 deletions.
diff --git a/libbpf-tools/biolatency.bpf.c b/libbpf-tools/biolatency.bpf.c
@@ -19,6 +19,10 @@ const volatile bool targ_ms = false;
 const volatile bool filter_dev = false;
 const volatile __u32 targ_dev = 0;
 
+struct request_queue___x {
+ struct gendisk *disk;
+} __attribute__((preserve_access_index));
+
 struct {
  __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
  __type(key, u32);
@@ -53,9 +57,15 @@ int trace_rq_start(struct request *rq, int issue)
  u64 ts = bpf_ktime_get_ns();
 
  if (filter_dev) {
- struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
+ struct request_queue___x *q = (void *)BPF_CORE_READ(rq, q);
+ struct gendisk *disk;
  u32 dev;
 
+ if (bpf_core_field_exists(q->disk))
+ disk = BPF_CORE_READ(q, disk);
+ else
+ disk = BPF_CORE_READ(rq, rq_disk);
+
  dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
  BPF_CORE_READ(disk, first_minor)) : 0;
  if (targ_dev != dev)
@@ -119,7 +129,13 @@ int BPF_PROG(block_rq_complete, struct request *rq, int error,
  goto cleanup;
 
  if (targ_per_disk) {
- struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
+ struct request_queue___x *q = (void *)BPF_CORE_READ(rq, q);
+ struct gendisk *disk;
+
+ if (bpf_core_field_exists(q->disk))
+ disk = BPF_CORE_READ(q, disk);
+ else
+ disk = BPF_CORE_READ(rq, rq_disk);
 
  hkey.dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
  BPF_CORE_READ(disk, first_minor)) : 0;

diff --git a/libbpf-tools/biosnoop.bpf.c b/libbpf-tools/biosnoop.bpf.c
@@ -15,6 +15,10 @@ const volatile __u32 targ_dev = 0;
 
 extern __u32 LINUX_KERNEL_VERSION __kconfig;
 
+struct request_queue___x {
+ struct gendisk *disk;
+} __attribute__((preserve_access_index));
+
 struct {
  __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
  __type(key, u32);
@@ -92,7 +96,13 @@ int trace_rq_start(struct request *rq, bool insert)
 
  stagep = bpf_map_lookup_elem(&start, &rq);
  if (!stagep) {
- struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
+ struct request_queue___x *q = (void *)BPF_CORE_READ(rq, q);
+ struct gendisk *disk;
+
+ if (bpf_core_field_exists(q->disk))
+ disk = BPF_CORE_READ(q, disk);
+ else
+ disk = BPF_CORE_READ(rq, rq_disk);
 
  stage.dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
  BPF_CORE_READ(disk, first_minor)) : 0;

diff --git a/libbpf-tools/biostacks.bpf.c b/libbpf-tools/biostacks.bpf.c
@@ -14,6 +14,10 @@ const volatile bool targ_ms = false;
 const volatile bool filter_dev = false;
 const volatile __u32 targ_dev = -1;
 
+struct request_queue___x {
+ struct gendisk *disk;
+} __attribute__((preserve_access_index));
+
 struct internal_rqinfo {
  u64 start_ts;
  struct rqinfo rqinfo;
@@ -41,9 +45,15 @@ static __always_inline
 int trace_start(void *ctx, struct request *rq, bool merge_bio)
 {
  struct internal_rqinfo *i_rqinfop = NULL, i_rqinfo = {};
- struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
+ struct request_queue___x *q = (void *)BPF_CORE_READ(rq, q);
+ struct gendisk *disk;
  u32 dev;
 
+ if (bpf_core_field_exists(q->disk))
+ disk = BPF_CORE_READ(q, disk);
+ else
+ disk = BPF_CORE_READ(rq, rq_disk);
+
  dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
  BPF_CORE_READ(disk, first_minor)) : 0;
  if (filter_dev && targ_dev != dev)

diff --git a/libbpf-tools/bitesize.bpf.c b/libbpf-tools/bitesize.bpf.c
@@ -13,6 +13,10 @@ const volatile __u32 targ_dev = 0;
 
 extern __u32 LINUX_KERNEL_VERSION __kconfig;
 
+struct request_queue___x {
+ struct gendisk *disk;
+} __attribute__((preserve_access_index));
+
 struct {
  __uint(type, BPF_MAP_TYPE_HASH);
  __uint(max_entries, 10240);
@@ -41,9 +45,15 @@ static int trace_rq_issue(struct request *rq)
  u64 slot;
 
  if (filter_dev) {
- struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
+ struct request_queue___x *q = (void *)BPF_CORE_READ(rq, q);
+ struct gendisk *disk;
  u32 dev;
 
+ if (bpf_core_field_exists(q->disk))
+ disk = BPF_CORE_READ(q, disk);
+ else
+ disk = BPF_CORE_READ(rq, rq_disk);
+
  dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
  BPF_CORE_READ(disk, first_minor)) : 0;
  if (targ_dev != dev)