diff mbox series

[bpf-next,v2,2/5] bpf: task_group_seq_get_next: cleanup the usage of get/put_task_struct

Message ID 20230905154649.GA24935@redhat.com (mailing list archive)
State Accepted
Commit ad98e2e5f84f130f4679176a1f382e75050502c5
Delegated to: BPF
Headers show
Series bpf: task_group_seq_get_next: misc cleanups | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-20 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-21 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-8 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-14 fail Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-17 fail Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-10 fail Logs for test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-13 fail Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-12 fail Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-18 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-16 fail Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-22 success Logs for test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-23 success Logs for test_progs_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-24 success Logs for test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-25 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-26 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-27 success Logs for test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-28 success Logs for veristat
bpf/vmtest-bpf-next-VM_Test-11 fail Logs for test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-15 fail Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-19 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1332 this patch: 1332
netdev/cc_maintainers warning 10 maintainers not CCed: martin.lau@linux.dev jolsa@kernel.org haoluo@google.com daniel@iogearbox.net ast@kernel.org sdf@google.com john.fastabend@gmail.com andrii@kernel.org kpsingh@kernel.org song@kernel.org
netdev/build_clang success Errors and warnings before: 1353 this patch: 1353
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1355 this patch: 1355
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 41 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-2 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-0 success Logs for ${{ matrix.test }} on ${{ matrix.arch }} with ${{ matrix.toolchain_full }}
bpf/vmtest-bpf-next-VM_Test-5 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-7 success Logs for veristat
bpf/vmtest-bpf-next-VM_Test-6 success Logs for set-matrix
bpf/vmtest-bpf-next-PR success PR summary

Commit Message

Oleg Nesterov Sept. 5, 2023, 3:46 p.m. UTC 
get_pid_task() makes no sense, the code does put_task_struct() soon after.
Use find_task_by_pid_ns() instead of find_pid_ns + get_pid_task and kill
put_task_struct(), this allows to do get_task_struct() only once before
return.

While at it, kill the unnecessary "if (!pid)" check in the "if (!*tid)"
block, this matches the next usage of find_pid_ns() + get_pid_task() in
this function.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
---
 kernel/bpf/task_iter.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 4d1125108014..1589ec3faded 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -42,9 +42,6 @@  static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_comm
 	if (!*tid) {
 		/* The first time, the iterator calls this function. */
 		pid = find_pid_ns(common->pid, common->ns);
-		if (!pid)
-			return NULL;
-
 		task = get_pid_task(pid, PIDTYPE_TGID);
 		if (!task)
 			return NULL;
@@ -66,17 +63,12 @@  static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_comm
 		return task;
 	}
 
-	pid = find_pid_ns(common->pid_visiting, common->ns);
-	if (!pid)
-		return NULL;
-
-	task = get_pid_task(pid, PIDTYPE_PID);
+	task = find_task_by_pid_ns(common->pid_visiting, common->ns);
 	if (!task)
 		return NULL;
 
 retry:
 	next_task = next_thread(task);
-	put_task_struct(task);
 
 	saved_tid = *tid;
 	*tid = __task_pid_nr_ns(next_task, PIDTYPE_PID, common->ns);
@@ -88,7 +80,6 @@  static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_comm
 		return NULL;
 	}
 
-	get_task_struct(next_task);
 	common->pid_visiting = *tid;
 
 	if (skip_if_dup_files && task->files == task->group_leader->files) {
@@ -96,6 +87,7 @@  static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_comm
 		goto retry;
 	}
 
+	get_task_struct(next_task);
 	return next_task;
 }