On Tue, Oct 9, 2018 at 6:05 AM Mauricio Vasquez
<mauricio.vasq...@polito.it> wrote:
>
>
>
> On 10/08/2018 08:36 PM, Song Liu wrote:
> > On Mon, Oct 8, 2018 at 12:12 PM Mauricio Vasquez B
> > <mauricio.vasq...@polito.it> wrote:
> >> Queue/stack maps implement a FIFO/LIFO data storage for ebpf programs.
> >> These maps support peek, pop and push operations that are exposed to eBPF
> >> programs through the new bpf_map[peek/pop/push] helpers. Those operations
> >> are exposed to userspace applications through the already existing
> >> syscalls in the following way:
> >>
> >> BPF_MAP_LOOKUP_ELEM -> peek
> >> BPF_MAP_LOOKUP_AND_DELETE_ELEM -> pop
> >> BPF_MAP_UPDATE_ELEM -> push
> >>
> >> Queue/stack maps are implemented using a buffer, tail and head indexes,
> >> hence BPF_F_NO_PREALLOC is not supported.
> >>
> >> As opposite to other maps, queue and stack do not use RCU for protecting
> >> maps values, the bpf_map[peek/pop] have a ARG_PTR_TO_UNINIT_MAP_VALUE
> >> argument that is a pointer to a memory zone where to save the value of a
> >> map. Basically the same as ARG_PTR_TO_UNINIT_MEM, but the size has not
> >> be passed as an extra argument.
> >>
> >> Our main motivation for implementing queue/stack maps was to keep track
> >> of a pool of elements, like network ports in a SNAT, however we forsee
> >> other use cases, like for exampling saving last N kernel events in a map
> >> and then analysing from userspace.
> >>
> >> Signed-off-by: Mauricio Vasquez B <mauricio.vasq...@polito.it>
> >> ---
> >> include/linux/bpf.h | 7 +
> >> include/linux/bpf_types.h | 2
> >> include/uapi/linux/bpf.h | 35 ++++-
> >> kernel/bpf/Makefile | 2
> >> kernel/bpf/core.c | 3
> >> kernel/bpf/helpers.c | 43 ++++++
> >> kernel/bpf/queue_stack_maps.c | 288
> >> +++++++++++++++++++++++++++++++++++++++++
> >> kernel/bpf/syscall.c | 30 +++-
> >> kernel/bpf/verifier.c | 28 +++-
> >> net/core/filter.c | 6 +
> >> 10 files changed, 426 insertions(+), 18 deletions(-)
> >> create mode 100644 kernel/bpf/queue_stack_maps.c
> >>
> >> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> >> index 98c7eeb6d138..cad3bc5cffd1 100644
> >> --- a/include/linux/bpf.h
> >> +++ b/include/linux/bpf.h
> >> @@ -40,6 +40,9 @@ struct bpf_map_ops {
> >> int (*map_update_elem)(struct bpf_map *map, void *key, void
> >> *value, u64 flags);
> >> int (*map_delete_elem)(struct bpf_map *map, void *key);
> >> void *(*map_lookup_and_delete_elem)(struct bpf_map *map, void
> >> *key);
> >> + int (*map_push_elem)(struct bpf_map *map, void *value, u64 flags);
> >> + int (*map_pop_elem)(struct bpf_map *map, void *value);
> >> + int (*map_peek_elem)(struct bpf_map *map, void *value);
> >>
> >> /* funcs called by prog_array and perf_event_array map */
> >> void *(*map_fd_get_ptr)(struct bpf_map *map, struct file
> >> *map_file,
> >> @@ -139,6 +142,7 @@ enum bpf_arg_type {
> >> ARG_CONST_MAP_PTR, /* const argument used as pointer to
> >> bpf_map */
> >> ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */
> >> ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */
> >> + ARG_PTR_TO_UNINIT_MAP_VALUE, /* pointer to valid memory used to
> >> store a map value */
> > How about we put ARG_PTR_TO_UNINIT_MAP_VALUE and related logic to a
> > separate patch?
>
> I thought it too, but this is a really small change (6 additions, 3
> deletions). Does it worth a separated patch?
I think a separate patch is better. You can also put small changes in
uapi header
in a separate patch.
Thanks,
Song
> >
> >> /* the following constraints used to prototype bpf_memcmp() and
> >> other
> >> * functions that access data on eBPF program stack
> >> @@ -825,6 +829,9 @@ static inline int
> >> bpf_fd_reuseport_array_update_elem(struct bpf_map *map,
> >> extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
> >> extern const struct bpf_func_proto bpf_map_update_elem_proto;
> >> extern const struct bpf_func_proto bpf_map_delete_elem_proto;
> >> +extern const struct bpf_func_proto bpf_map_push_elem_proto;
> >> +extern const struct bpf_func_proto bpf_map_pop_elem_proto;
> >> +extern const struct bpf_func_proto bpf_map_peek_elem_proto;
> >>
> >> extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
> >> extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
> >> diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> >> index 658509daacd4..a2ec73aa1ec7 100644
> >> --- a/include/linux/bpf_types.h
> >> +++ b/include/linux/bpf_types.h
> >> @@ -69,3 +69,5 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops)
> >> BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops)
> >> #endif
> >> #endif
> >> +BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops)
> >> +BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops)
> >> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> >> index 3bb94aa2d408..bfa042273fad 100644
> >> --- a/include/uapi/linux/bpf.h
> >> +++ b/include/uapi/linux/bpf.h
> >> @@ -129,6 +129,8 @@ enum bpf_map_type {
> >> BPF_MAP_TYPE_CGROUP_STORAGE,
> >> BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
> >> BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
> >> + BPF_MAP_TYPE_QUEUE,
> >> + BPF_MAP_TYPE_STACK,
> >> };
> >>
> >> enum bpf_prog_type {
> >> @@ -463,6 +465,28 @@ union bpf_attr {
> >> * Return
> >> * 0 on success, or a negative error in case of failure.
> >> *
> >> + * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64
> >> flags)
> >> + * Description
> >> + * Push an element *value* in *map*. *flags* is one of:
> >> + *
> >> + * **BPF_EXIST**
> >> + * If the queue/stack is full, the oldest element is removed
> >> to
> >> + * make room for this.
> >> + * Return
> >> + * 0 on success, or a negative error in case of failure.
> >> + *
> >> + * int bpf_map_pop_elem(struct bpf_map *map, void *value)
> >> + * Description
> >> + * Pop an element from *map*.
> >> + * Return
> >> + * 0 on success, or a negative error in case of failure.
> >> + *
> >> + * int bpf_map_peek_elem(struct bpf_map *map, void *value)
> >> + * Description
> >> + * Get an element from *map* without removing it.
> >> + * Return
> >> + * 0 on success, or a negative error in case of failure.
> >> + *
> >> * int bpf_probe_read(void *dst, u32 size, const void *src)
> >> * Description
> >> * For tracing programs, safely attempt to read *size* bytes
> >> from
> >> @@ -790,14 +814,14 @@ union bpf_attr {
> >> *
> >> * int ret;
> >> * struct bpf_tunnel_key key = {};
> >> - *
> >> + *
> >> * ret = bpf_skb_get_tunnel_key(skb, &key,
> >> sizeof(key), 0);
> >> * if (ret < 0)
> >> * return TC_ACT_SHOT; // drop packet
> >> - *
> >> + *
> >> * if (key.remote_ipv4 != 0x0a000001)
> >> * return TC_ACT_SHOT; // drop packet
> >> - *
> >> + *
> >> * return TC_ACT_OK; // accept packet
> >> *
> >> * This interface can also be used with all encapsulation
> >> devices
> >> @@ -2304,7 +2328,10 @@ union bpf_attr {
> >> FN(skb_ancestor_cgroup_id), \
> >> FN(sk_lookup_tcp), \
> >> FN(sk_lookup_udp), \
> >> - FN(sk_release),
> >> + FN(sk_release), \
> >> + FN(map_push_elem), \
> >> + FN(map_pop_elem), \
> >> + FN(map_peek_elem),
> >>
> >> /* integer value in 'imm' field of BPF_CALL instruction selects which
> >> helper
> >> * function eBPF program intends to call
> >> diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
> >> index 0488b8258321..17afae9e65f3 100644
> >> --- a/kernel/bpf/Makefile
> >> +++ b/kernel/bpf/Makefile
> >> @@ -3,7 +3,7 @@ obj-y := core.o
> >>
> >> obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o
> >> tnum.o
> >> obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o
> >> bpf_lru_list.o lpm_trie.o map_in_map.o
> >> -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o
> >> +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o
> >> obj-$(CONFIG_BPF_SYSCALL) += disasm.o
> >> obj-$(CONFIG_BPF_SYSCALL) += btf.o
> >> ifeq ($(CONFIG_NET),y)
> >> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> >> index 3f5bf1af0826..8d2db076d123 100644
> >> --- a/kernel/bpf/core.c
> >> +++ b/kernel/bpf/core.c
> >> @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32)
> >> const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
> >> const struct bpf_func_proto bpf_map_update_elem_proto __weak;
> >> const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
> >> +const struct bpf_func_proto bpf_map_push_elem_proto __weak;
> >> +const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
> >> +const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
> >>
> >> const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
> >> const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
> >> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> >> index 6502115e8f55..ab0d5e3f9892 100644
> >> --- a/kernel/bpf/helpers.c
> >> +++ b/kernel/bpf/helpers.c
> >> @@ -76,6 +76,49 @@ const struct bpf_func_proto bpf_map_delete_elem_proto =
> >> {
> >> .arg2_type = ARG_PTR_TO_MAP_KEY,
> >> };
> >>
> >> +BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64,
> >> flags)
> >> +{
> >> + return map->ops->map_push_elem(map, value, flags);
> >> +}
> >> +
> >> +const struct bpf_func_proto bpf_map_push_elem_proto = {
> >> + .func = bpf_map_push_elem,
> >> + .gpl_only = false,
> >> + .pkt_access = true,
> >> + .ret_type = RET_INTEGER,
> >> + .arg1_type = ARG_CONST_MAP_PTR,
> >> + .arg2_type = ARG_PTR_TO_MAP_VALUE,
> >> + .arg3_type = ARG_ANYTHING,
> >> +};
> >> +
> >> +BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
> >> +{
> >> + return map->ops->map_pop_elem(map, value);
> >> +}
> >> +
> >> +const struct bpf_func_proto bpf_map_pop_elem_proto = {
> >> + .func = bpf_map_pop_elem,
> >> + .gpl_only = false,
> >> + .pkt_access = true,
> >> + .ret_type = RET_INTEGER,
> >> + .arg1_type = ARG_CONST_MAP_PTR,
> >> + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE,
> >> +};
> >> +
> >> +BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
> >> +{
> >> + return map->ops->map_peek_elem(map, value);
> >> +}
> >> +
> >> +const struct bpf_func_proto bpf_map_peek_elem_proto = {
> >> + .func = bpf_map_pop_elem,
> >> + .gpl_only = false,
> >> + .pkt_access = true,
> >> + .ret_type = RET_INTEGER,
> >> + .arg1_type = ARG_CONST_MAP_PTR,
> >> + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE,
> >> +};
> >> +
> >> const struct bpf_func_proto bpf_get_prandom_u32_proto = {
> >> .func = bpf_user_rnd_u32,
> >> .gpl_only = false,
> >> diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c
> >> new file mode 100644
> >> index 000000000000..12a93fb37449
> >> --- /dev/null
> >> +++ b/kernel/bpf/queue_stack_maps.c
> >> @@ -0,0 +1,288 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * queue_stack_maps.c: BPF queue and stack maps
> >> + *
> >> + * Copyright (c) 2018 Politecnico di Torino
> >> + */
> >> +#include <linux/bpf.h>
> >> +#include <linux/list.h>
> >> +#include <linux/slab.h>
> >> +#include "percpu_freelist.h"
> >> +
> >> +#define QUEUE_STACK_CREATE_FLAG_MASK \
> >> + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
> >> +
> >> +
> >> +struct bpf_queue_stack {
> >> + struct bpf_map map;
> >> + raw_spinlock_t lock;
> >> + u32 head, tail;
> >> + u32 size; /* max_entries + 1 */
> >> +
> >> + char elements[0] __aligned(8);
> >> +};
> >> +
> >> +static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map)
> >> +{
> >> + return container_of(map, struct bpf_queue_stack, map);
> >> +}
> >> +
> >> +static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs)
> >> +{
> >> + return qs->head == qs->tail;
> >> +}
> >> +
> >> +static bool queue_stack_map_is_full(struct bpf_queue_stack *qs)
> >> +{
> >> + u32 head = qs->head + 1;
> >> +
> >> + if (unlikely(head >= qs->size))
> >> + head = 0;
> >> +
> >> + return head == qs->tail;
> >> +}
> >> +
> >> +/* Called from syscall */
> >> +static int queue_stack_map_alloc_check(union bpf_attr *attr)
> >> +{
> >> + /* check sanity of attributes */
> >> + if (attr->max_entries == 0 || attr->key_size != 0 ||
> >> + attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK)
> >> + return -EINVAL;
> >> +
> >> + if (attr->value_size > KMALLOC_MAX_SIZE)
> >> + /* if value_size is bigger, the user space won't be able to
> >> + * access the elements.
> >> + */
> >> + return -E2BIG;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr)
> >> +{
> >> + int ret, numa_node = bpf_map_attr_numa_node(attr);
> >> + struct bpf_queue_stack *qs;
> >> + u32 size, value_size;
> >> + u64 queue_size, cost;
> >> +
> >> + size = attr->max_entries + 1;
> >> + value_size = attr->value_size;
> >> +
> >> + queue_size = sizeof(*qs) + (u64) value_size * size;
> >> +
> >> + cost = queue_size;
> >> + if (cost >= U32_MAX - PAGE_SIZE)
> >> + return ERR_PTR(-E2BIG);
> >> +
> >> + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
> >> +
> >> + ret = bpf_map_precharge_memlock(cost);
> >> + if (ret < 0)
> >> + return ERR_PTR(ret);
> >> +
> >> + qs = bpf_map_area_alloc(queue_size, numa_node);
> >> + if (!qs)
> >> + return ERR_PTR(-ENOMEM);
> >> +
> >> + memset(qs, 0, sizeof(*qs));
> >> +
> >> + bpf_map_init_from_attr(&qs->map, attr);
> >> +
> >> + qs->map.pages = cost;
> >> + qs->size = size;
> >> +
> >> + raw_spin_lock_init(&qs->lock);
> >> +
> >> + return &qs->map;
> >> +}
> >> +
> >> +/* Called when map->refcnt goes to zero, either from workqueue or from
> >> syscall */
> >> +static void queue_stack_map_free(struct bpf_map *map)
> >> +{
> >> + struct bpf_queue_stack *qs = bpf_queue_stack(map);
> >> +
> >> + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt
> >> == 0,
> >> + * so the programs (can be more than one that used this map) were
> >> + * disconnected from events. Wait for outstanding critical
> >> sections in
> >> + * these programs to complete
> >> + */
> >> + synchronize_rcu();
> >> +
> >> + bpf_map_area_free(qs);
> >> +}
> >> +
> >> +static int __queue_map_get(struct bpf_map *map, void *value, bool delete)
> >> +{
> >> + struct bpf_queue_stack *qs = bpf_queue_stack(map);
> >> + unsigned long flags;
> >> + int err = 0;
> >> + void *ptr;
> >> +
> >> + raw_spin_lock_irqsave(&qs->lock, flags);
> >> +
> >> + if (queue_stack_map_is_empty(qs)) {
> >> + err = -ENOENT;
> >> + goto out;
> >> + }
> >> +
> >> + ptr = &qs->elements[qs->tail * qs->map.value_size];
> >> + memcpy(value, ptr, qs->map.value_size);
> >> +
> >> + if (delete) {
> >> + if (unlikely(++qs->tail >= qs->size))
> >> + qs->tail = 0;
> >> + }
> >> +
> >> +out:
> >> + raw_spin_unlock_irqrestore(&qs->lock, flags);
> >> + return err;
> >> +}
> >> +
> >> +
> >> +static int __stack_map_get(struct bpf_map *map, void *value, bool delete)
> >> +{
> >> + struct bpf_queue_stack *qs = bpf_queue_stack(map);
> >> + unsigned long flags;
> >> + int err = 0;
> >> + void *ptr;
> >> + u32 index;
> >> +
> >> + raw_spin_lock_irqsave(&qs->lock, flags);
> >> +
> >> + if (queue_stack_map_is_empty(qs)) {
> >> + err = -ENOENT;
> >> + goto out;
> >> + }
> >> +
> >> + index = qs->head - 1;
> >> + if (unlikely(index >= qs->size))
> >> + index = qs->size - 1;
> >> +
> >> + ptr = &qs->elements[index * qs->map.value_size];
> >> + memcpy(value, ptr, qs->map.value_size);
> >> +
> >> + if (delete)
> >> + qs->head = index;
> >> +
> >> +out:
> >> + raw_spin_unlock_irqrestore(&qs->lock, flags);
> >> + return err;
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int queue_map_peek_elem(struct bpf_map *map, void *value)
> >> +{
> >> + return __queue_map_get(map, value, false);
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int stack_map_peek_elem(struct bpf_map *map, void *value)
> >> +{
> >> + return __stack_map_get(map, value, false);
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int queue_map_pop_elem(struct bpf_map *map, void *value)
> >> +{
> >> + return __queue_map_get(map, value, true);
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int stack_map_pop_elem(struct bpf_map *map, void *value)
> >> +{
> >> + return __stack_map_get(map, value, true);
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int queue_stack_map_push_elem(struct bpf_map *map, void *value,
> >> + u64 flags)
> >> +{
> >> + struct bpf_queue_stack *qs = bpf_queue_stack(map);
> >> + unsigned long irq_flags;
> >> + int err = 0;
> >> + void *dst;
> >> +
> >> + /* BPF_EXIST is used to force making room for a new element in
> >> case the
> >> + * map is full
> >> + */
> >> + bool replace = (flags & BPF_EXIST);
> >> +
> >> + /* Check supported flags for queue and stack maps */
> >> + if (flags & BPF_NOEXIST || flags > BPF_EXIST)
> >> + return -EINVAL;
> >> +
> >> + raw_spin_lock_irqsave(&qs->lock, irq_flags);
> >> +
> >> + if (queue_stack_map_is_full(qs)) {
> >> + if (!replace) {
> >> + err = -E2BIG;
> >> + goto out;
> >> + }
> >> + /* advance tail pointer to overwrite oldest element */
> >> + if (unlikely(++qs->tail >= qs->size))
> >> + qs->tail = 0;
> >> + }
> >> +
> >> + dst = &qs->elements[qs->head * qs->map.value_size];
> >> + memcpy(dst, value, qs->map.value_size);
> >> +
> >> + if (unlikely(++qs->head >= qs->size))
> >> + qs->head = 0;
> >> +
> >> +out:
> >> + raw_spin_unlock_irqrestore(&qs->lock, irq_flags);
> >> + return err;
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key)
> >> +{
> >> + return NULL;
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int queue_stack_map_update_elem(struct bpf_map *map, void *key,
> >> + void *value, u64 flags)
> >> +{
> >> + return -EINVAL;
> >> +}
> >> +
> >> +/* Called from syscall or from eBPF program */
> >> +static int queue_stack_map_delete_elem(struct bpf_map *map, void *key)
> >> +{
> >> + return -EINVAL;
> >> +}
> >> +
> >> +/* Called from syscall */
> >> +static int queue_stack_map_get_next_key(struct bpf_map *map, void *key,
> >> + void *next_key)
> >> +{
> >> + return -EINVAL;
> >> +}
> >> +
> >> +const struct bpf_map_ops queue_map_ops = {
> >> + .map_alloc_check = queue_stack_map_alloc_check,
> >> + .map_alloc = queue_stack_map_alloc,
> >> + .map_free = queue_stack_map_free,
> >> + .map_lookup_elem = queue_stack_map_lookup_elem,
> >> + .map_update_elem = queue_stack_map_update_elem,
> >> + .map_delete_elem = queue_stack_map_delete_elem,
> >> + .map_push_elem = queue_stack_map_push_elem,
> >> + .map_pop_elem = queue_map_pop_elem,
> >> + .map_peek_elem = queue_map_peek_elem,
> >> + .map_get_next_key = queue_stack_map_get_next_key,
> >> +};
> >> +
> >> +const struct bpf_map_ops stack_map_ops = {
> >> + .map_alloc_check = queue_stack_map_alloc_check,
> >> + .map_alloc = queue_stack_map_alloc,
> >> + .map_free = queue_stack_map_free,
> >> + .map_lookup_elem = queue_stack_map_lookup_elem,
> >> + .map_update_elem = queue_stack_map_update_elem,
> >> + .map_delete_elem = queue_stack_map_delete_elem,
> >> + .map_push_elem = queue_stack_map_push_elem,
> >> + .map_pop_elem = stack_map_pop_elem,
> >> + .map_peek_elem = stack_map_peek_elem,
> >> + .map_get_next_key = queue_stack_map_get_next_key,
> >> +};
> >> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> >> index c33d9303f72f..c135d205fd09 100644
> >> --- a/kernel/bpf/syscall.c
> >> +++ b/kernel/bpf/syscall.c
> >> @@ -727,6 +727,9 @@ static int map_lookup_elem(union bpf_attr *attr)
> >> err = bpf_fd_htab_map_lookup_elem(map, key, value);
> >> } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
> >> err = bpf_fd_reuseport_array_lookup_elem(map, key, value);
> >> + } else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
> >> + map->map_type == BPF_MAP_TYPE_STACK) {
> >> + err = map->ops->map_peek_elem(map, value);
> >> } else {
> >> rcu_read_lock();
> >> ptr = map->ops->map_lookup_elem(map, key);
> >> @@ -841,6 +844,9 @@ static int map_update_elem(union bpf_attr *attr)
> >> /* rcu_read_lock() is not needed */
> >> err = bpf_fd_reuseport_array_update_elem(map, key, value,
> >> attr->flags);
> >> + } else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
> >> + map->map_type == BPF_MAP_TYPE_STACK) {
> >> + err = map->ops->map_push_elem(map, value, attr->flags);
> >> } else {
> >> rcu_read_lock();
> >> err = map->ops->map_update_elem(map, key, value,
> >> attr->flags);
> >> @@ -1023,16 +1029,22 @@ static int map_lookup_and_delete_elem(union
> >> bpf_attr *attr)
> >> */
> >> preempt_disable();
> >> __this_cpu_inc(bpf_prog_active);
> >> - if (!map->ops->map_lookup_and_delete_elem) {
> >> - err = -ENOTSUPP;
> >> - goto free_value;
> >> + if (map->map_type == BPF_MAP_TYPE_QUEUE ||
> >> + map->map_type == BPF_MAP_TYPE_STACK) {
> >> + err = map->ops->map_pop_elem(map, value);
> >> + } else {
> >> + if (!map->ops->map_lookup_and_delete_elem) {
> >> + err = -ENOTSUPP;
> >> + goto free_value;
> > similar to previous patch: either we move this check, or we add
> > __this_cpu_dec() and preempt_enable().
>
> In this case the check cannot be moved, I'll change it to fix the
> problem and make it more readable.
>
> >
> > Thanks,
> > Song
> >
>
