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IB/core: Implement a limit on UMAD receive List

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[ Upstream commit ca0b44e20a ]

The existing behavior of ib_umad, which maintains received MAD
packets in an unbounded list, poses a risk of uncontrolled growth.
As user-space applications extract packets from this list, the rate
of extraction may not match the rate of incoming packets, leading
to potential list overflow.

To address this, we introduce a limit to the size of the list. After
considering typical scenarios, such as OpenSM processing, which can
handle approximately 100k packets per second, and the 1-second retry
timeout for most packets, we set the list size limit to 200k. Packets
received beyond this limit are dropped, assuming they are likely timed
out by the time they are handled by user-space.

Notably, packets queued on the receive list due to reasons like
timed-out sends are preserved even when the list is full.

Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Reviewed-by: Mark Zhang <markzhang@nvidia.com>
Link: https://lore.kernel.org/r/7197cb58a7d9e78399008f25036205ceab07fbd5.1713268818.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Michael Guralnik 2024-04-16 15:01:44 +03:00 committed by Greg Kroah-Hartman
parent f273ea5eb8
commit b491370241
1 changed files with 15 additions and 6 deletions
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21
drivers/infiniband/core/user_mad.c
View File

@ -63,6 +63,8 @@ MODULE_AUTHOR("Roland Dreier");
MODULE_DESCRIPTION("InfiniBand userspace MAD packet access");
MODULE_LICENSE("Dual BSD/GPL");
#define MAX_UMAD_RECV_LIST_SIZE 200000
enum {
IB_UMAD_MAX_PORTS = RDMA_MAX_PORTS,
IB_UMAD_MAX_AGENTS = 32,
@ -113,6 +115,7 @@ struct ib_umad_file {
struct mutex mutex;
struct ib_umad_port *port;
struct list_head recv_list;
atomic_t recv_list_size;
struct list_head send_list;
struct list_head port_list;
spinlock_t send_lock;
@ -180,24 +183,28 @@ static struct ib_mad_agent *__get_agent(struct ib_umad_file *file, int id)
return file->agents_dead ? NULL : file->agent[id];
}
static int queue_packet(struct ib_umad_file *file,
struct ib_mad_agent *agent,
struct ib_umad_packet *packet)
static int queue_packet(struct ib_umad_file *file, struct ib_mad_agent *agent,
struct ib_umad_packet *packet, bool is_recv_mad)
{
int ret = 1;
mutex_lock(&file->mutex);
if (is_recv_mad &&
atomic_read(&file->recv_list_size) > MAX_UMAD_RECV_LIST_SIZE)
goto unlock;
for (packet->mad.hdr.id = 0;
packet->mad.hdr.id < IB_UMAD_MAX_AGENTS;
packet->mad.hdr.id++)
if (agent == __get_agent(file, packet->mad.hdr.id)) {
list_add_tail(&packet->list, &file->recv_list);
atomic_inc(&file->recv_list_size);
wake_up_interruptible(&file->recv_wait);
ret = 0;
break;
}
unlock:
mutex_unlock(&file->mutex);
return ret;
@ -224,7 +231,7 @@ static void send_handler(struct ib_mad_agent *agent,
if (send_wc->status == IB_WC_RESP_TIMEOUT_ERR) {
packet->length = IB_MGMT_MAD_HDR;
packet->mad.hdr.status = ETIMEDOUT;
if (!queue_packet(file, agent, packet))
if (!queue_packet(file, agent, packet, false))
return;
}
kfree(packet);
@ -284,7 +291,7 @@ static void recv_handler(struct ib_mad_agent *agent,
rdma_destroy_ah_attr(&ah_attr);
}
if (queue_packet(file, agent, packet))
if (queue_packet(file, agent, packet, true))
goto err2;
return;
@ -409,6 +416,7 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
packet = list_entry(file->recv_list.next, struct ib_umad_packet, list);
list_del(&packet->list);
atomic_dec(&file->recv_list_size);
mutex_unlock(&file->mutex);
@ -421,6 +429,7 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
/* Requeue packet */
mutex_lock(&file->mutex);
list_add(&packet->list, &file->recv_list);
atomic_inc(&file->recv_list_size);
mutex_unlock(&file->mutex);
} else {
if (packet->recv_wc)