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Merge branch 'Two fixes for cpu-map'

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Hou Tao says:

====================

The patchset fixes two reported warning in cpu-map when running
xdp_redirect_cpu and some RT threads concurrently. Patch #1 fixes
the warning in __cpu_map_ring_cleanup() when kthread is stopped
prematurely. Patch #2 fixes the warning in __xdp_return() when
there are pending skbs in ptr_ring.

Please see individual patches for more details. And comments are always
welcome.

====================

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Martin KaFai Lau
2023-07-31 15:37:13 -07:00
parent bcc29b7f5a 7c62b75cd1
commit 4c9fbff542
1 changed files with 21 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
kernel/bpf/cpumap.c
View File

@@ -28,6 +28,7 @@
#include <linux/sched.h>
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <linux/completion.h>
#include <trace/events/xdp.h>
#include <linux/btf_ids.h>
@@ -73,6 +74,7 @@ struct bpf_cpu_map_entry {
struct rcu_head rcu;
struct work_struct kthread_stop_wq;
struct completion kthread_running;
};
struct bpf_cpu_map {
@@ -129,11 +131,17 @@ static void __cpu_map_ring_cleanup(struct ptr_ring *ring)
* invoked cpu_map_kthread_stop(). Catch any broken behaviour
* gracefully and warn once.
*/
struct xdp_frame *xdpf;
void *ptr;
while ((xdpf = ptr_ring_consume(ring)))
if (WARN_ON_ONCE(xdpf))
xdp_return_frame(xdpf);
while ((ptr = ptr_ring_consume(ring))) {
WARN_ON_ONCE(1);
if (unlikely(__ptr_test_bit(0, &ptr))) {
__ptr_clear_bit(0, &ptr);
kfree_skb(ptr);
continue;
}
xdp_return_frame(ptr);
}
}
static void put_cpu_map_entry(struct bpf_cpu_map_entry *rcpu)
@@ -153,7 +161,6 @@ static void put_cpu_map_entry(struct bpf_cpu_map_entry *rcpu)
static void cpu_map_kthread_stop(struct work_struct *work)
{
struct bpf_cpu_map_entry *rcpu;
int err;
rcpu = container_of(work, struct bpf_cpu_map_entry, kthread_stop_wq);
@@ -163,14 +170,7 @@ static void cpu_map_kthread_stop(struct work_struct *work)
rcu_barrier();
/* kthread_stop will wake_up_process and wait for it to complete */
err = kthread_stop(rcpu->kthread);
if (err) {
/* kthread_stop may be called before cpu_map_kthread_run
* is executed, so we need to release the memory related
* to rcpu.
*/
put_cpu_map_entry(rcpu);
}
kthread_stop(rcpu->kthread);
}
static void cpu_map_bpf_prog_run_skb(struct bpf_cpu_map_entry *rcpu,
@@ -298,11 +298,11 @@ static int cpu_map_bpf_prog_run(struct bpf_cpu_map_entry *rcpu, void **frames,
return nframes;
}
static int cpu_map_kthread_run(void *data)
{
struct bpf_cpu_map_entry *rcpu = data;
complete(&rcpu->kthread_running);
set_current_state(TASK_INTERRUPTIBLE);
/* When kthread gives stop order, then rcpu have been disconnected
@@ -467,6 +467,7 @@ __cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value,
goto free_ptr_ring;
/* Setup kthread */
init_completion(&rcpu->kthread_running);
rcpu->kthread = kthread_create_on_node(cpu_map_kthread_run, rcpu, numa,
"cpumap/%d/map:%d", cpu,
map->id);
@@ -480,6 +481,12 @@ __cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value,
kthread_bind(rcpu->kthread, cpu);
wake_up_process(rcpu->kthread);
/* Make sure kthread has been running, so kthread_stop() will not
* stop the kthread prematurely and all pending frames or skbs
* will be handled by the kthread before kthread_stop() returns.
*/
wait_for_completion(&rcpu->kthread_running);
return rcpu;
free_prog: