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Message-ID: <881e43f8-54e0-4847-67c4-82b9c0b3e50c@linux.ibm.com>
Date:   Fri, 22 Sep 2023 01:31:52 +0200
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From:   Wenjia Zhang <wenjia@linux.ibm.com>
Subject: Re: [PATCH net-next v3 12/18] net/smc: implement DMB-related
 operations of loopback
To:     Wen Gu <guwen@linux.alibaba.com>, kgraul@linux.ibm.com,
        jaka@linux.ibm.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com
Cc:     alibuda@linux.alibaba.com, tonylu@linux.alibaba.com,
        linux-s390@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1695302360-46691-1-git-send-email-guwen@linux.alibaba.com>
 <1695302360-46691-13-git-send-email-guwen@linux.alibaba.com>
In-Reply-To: <1695302360-46691-13-git-send-email-guwen@linux.alibaba.com>
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On 21.09.23 15:19, Wen Gu wrote:
> This patch implements DMB registration, unregistration and data move
> operations of SMC-D loopback.
> 
> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
> ---
>   net/smc/smc_cdc.c      |   6 +++
>   net/smc/smc_cdc.h      |   1 +
>   net/smc/smc_loopback.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++--
>   net/smc/smc_loopback.h |  13 +++++
>   4 files changed, 145 insertions(+), 3 deletions(-)
> 
> diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
> index 89105e9..2641800 100644
> --- a/net/smc/smc_cdc.c
> +++ b/net/smc/smc_cdc.c
> @@ -411,6 +411,12 @@ static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
>   static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
>   {
>   	struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
> +
> +	smcd_cdc_rx_handler(conn);
> +}
> +
> +void smcd_cdc_rx_handler(struct smc_connection *conn)
> +{
>   	struct smcd_cdc_msg *data_cdc;
>   	struct smcd_cdc_msg cdc;
>   	struct smc_sock *smc;
> diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h
> index 696cc11..11559d4 100644
> --- a/net/smc/smc_cdc.h
> +++ b/net/smc/smc_cdc.h
> @@ -301,5 +301,6 @@ int smcr_cdc_msg_send_validation(struct smc_connection *conn,
>   				 struct smc_wr_buf *wr_buf);
>   int smc_cdc_init(void) __init;
>   void smcd_cdc_rx_init(struct smc_connection *conn);
> +void smcd_cdc_rx_handler(struct smc_connection *conn);
>   
>   #endif /* SMC_CDC_H */
> diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
> index 9034ebd..cfbcabf 100644
> --- a/net/smc/smc_loopback.c
> +++ b/net/smc/smc_loopback.c
> @@ -16,6 +16,7 @@
>   #include <linux/smc.h>
>   #include <net/smc.h>
>   
> +#include "smc_cdc.h"
>   #include "smc_ism.h"
>   #include "smc_loopback.h"
>   
> @@ -74,6 +75,93 @@ static int smc_lo_query_rgid(struct smcd_dev *smcd, struct smcd_gid *rgid,
>   	return 0;
>   }
>   
> +static int smc_lo_register_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb,
> +			       void *client_priv)
> +{
> +	struct smc_lo_dmb_node *dmb_node, *tmp_node;
> +	struct smc_lo_dev *ldev = smcd->priv;
> +	int sba_idx, rc;
> +
> +	/* check space for new dmb */
> +	for_each_clear_bit(sba_idx, ldev->sba_idx_mask, SMC_LODEV_MAX_DMBS) {
> +		if (!test_and_set_bit(sba_idx, ldev->sba_idx_mask))
> +			break;
> +	}
> +	if (sba_idx == SMC_LODEV_MAX_DMBS)
> +		return -ENOSPC;
> +
> +	dmb_node = kzalloc(sizeof(*dmb_node), GFP_KERNEL);
> +	if (!dmb_node) {
> +		rc = -ENOMEM;
> +		goto err_bit;
> +	}
> +
> +	dmb_node->sba_idx = sba_idx;
> +	dmb_node->cpu_addr = kzalloc(dmb->dmb_len, GFP_KERNEL |
> +				     __GFP_NOWARN | __GFP_NORETRY |
> +				     __GFP_NOMEMALLOC);
kzalloc()/kmalloc() allocates physically contigueous memory. Are you 
sure it is suitable for allocating the dmb?

> +	if (!dmb_node->cpu_addr) {
> +		rc = -ENOMEM;
> +		goto err_node;
> +	}
> +	dmb_node->len = dmb->dmb_len;
> +	dmb_node->dma_addr = (dma_addr_t)dmb_node->cpu_addr;
> +
> +again:
> +	/* add new dmb into hash table */
> +	get_random_bytes(&dmb_node->token, sizeof(dmb_node->token));
> +	write_lock(&ldev->dmb_ht_lock);
> +	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_node->token) {
> +		if (tmp_node->token == dmb_node->token) {
> +			write_unlock(&ldev->dmb_ht_lock);
> +			goto again;
> +		}
> +	}
> +	hash_add(ldev->dmb_ht, &dmb_node->list, dmb_node->token);
> +	write_unlock(&ldev->dmb_ht_lock);
> +
> +	dmb->sba_idx = dmb_node->sba_idx;
> +	dmb->dmb_tok = dmb_node->token;
> +	dmb->cpu_addr = dmb_node->cpu_addr;
> +	dmb->dma_addr = dmb_node->dma_addr;
> +	dmb->dmb_len = dmb_node->len;
> +
> +	return 0;
> +
> +err_node:
> +	kfree(dmb_node);
> +err_bit:
> +	clear_bit(sba_idx, ldev->sba_idx_mask);
> +	return rc;
> +}
> +
> +static int smc_lo_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
> +{
> +	struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
> +	struct smc_lo_dev *ldev = smcd->priv;
> +
> +	/* remove dmb from hash table */
> +	write_lock(&ldev->dmb_ht_lock);
> +	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {
> +		if (tmp_node->token == dmb->dmb_tok) {
> +			dmb_node = tmp_node;
> +			break;
> +		}
> +	}
> +	if (!dmb_node) {
> +		write_unlock(&ldev->dmb_ht_lock);
> +		return -EINVAL;
> +	}
> +	hash_del(&dmb_node->list);
> +	write_unlock(&ldev->dmb_ht_lock);
> +
> +	clear_bit(dmb_node->sba_idx, ldev->sba_idx_mask);
> +	kfree(dmb_node->cpu_addr);
> +	kfree(dmb_node);
> +
> +	return 0;
> +}
> +
>   static int smc_lo_add_vlan_id(struct smcd_dev *smcd, u64 vlan_id)
>   {
>   	return -EOPNOTSUPP;
> @@ -100,6 +188,38 @@ static int smc_lo_signal_event(struct smcd_dev *dev, struct smcd_gid *rgid,
>   	return 0;
>   }
>   
> +static int smc_lo_move_data(struct smcd_dev *smcd, u64 dmb_tok, unsigned int idx,
> +			    bool sf, unsigned int offset, void *data,
> +			    unsigned int size)
> +{
> +	struct smc_lo_dmb_node *rmb_node = NULL, *tmp_node;
> +	struct smc_lo_dev *ldev = smcd->priv;
> +
> +	read_lock(&ldev->dmb_ht_lock);
> +	hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_tok) {
> +		if (tmp_node->token == dmb_tok) {
> +			rmb_node = tmp_node;
> +			break;
> +		}
> +	}
> +	if (!rmb_node) {
> +		read_unlock(&ldev->dmb_ht_lock);
> +		return -EINVAL;
> +	}
> +	read_unlock(&ldev->dmb_ht_lock);
> +
> +	memcpy((char *)rmb_node->cpu_addr + offset, data, size);
> +
> +	if (sf) {
> +		struct smc_connection *conn =
> +			smcd->conn[rmb_node->sba_idx];
> +
> +		if (conn && !conn->killed)
> +			smcd_cdc_rx_handler(conn);
> +	}
> +	return 0;
> +}
> +
>   static int smc_lo_supports_v2(void)
>   {
>   	return SMC_LO_SUPPORTS_V2;
> @@ -131,14 +251,14 @@ static struct device *smc_lo_get_dev(struct smcd_dev *smcd)
>   
>   static const struct smcd_ops lo_ops = {
>   	.query_remote_gid = smc_lo_query_rgid,
> -	.register_dmb		= NULL,
> -	.unregister_dmb		= NULL,
> +	.register_dmb = smc_lo_register_dmb,
> +	.unregister_dmb = smc_lo_unregister_dmb,
>   	.add_vlan_id = smc_lo_add_vlan_id,
>   	.del_vlan_id = smc_lo_del_vlan_id,
>   	.set_vlan_required = smc_lo_set_vlan_required,
>   	.reset_vlan_required = smc_lo_reset_vlan_required,
>   	.signal_event = smc_lo_signal_event,
> -	.move_data		= NULL,
> +	.move_data = smc_lo_move_data,
>   	.supports_v2 = smc_lo_supports_v2,
>   	.get_system_eid = smc_lo_get_system_eid,
>   	.get_local_gid = smc_lo_get_local_gid,
> @@ -212,6 +332,8 @@ static void smc_lo_dev_release(struct device *dev)
>   static int smc_lo_dev_init(struct smc_lo_dev *ldev)
>   {
>   	smc_lo_generate_id(ldev);
> +	rwlock_init(&ldev->dmb_ht_lock);
> +	hash_init(ldev->dmb_ht);
>   
>   	return smcd_lo_register_dev(ldev);
>   }
> diff --git a/net/smc/smc_loopback.h b/net/smc/smc_loopback.h
> index 2156f22..943424f 100644
> --- a/net/smc/smc_loopback.h
> +++ b/net/smc/smc_loopback.h
> @@ -20,12 +20,25 @@
>   
>   #define SMC_LO_CHID 0xFFFF
>   #define SMC_LODEV_MAX_DMBS 5000
> +#define SMC_LODEV_DMBS_HASH_BITS 12
> +
> +struct smc_lo_dmb_node {
> +	struct hlist_node list;
> +	u64 token;
> +	u32 len;
> +	u32 sba_idx;
> +	void *cpu_addr;
> +	dma_addr_t dma_addr;
> +};
>   
>   struct smc_lo_dev {
>   	struct smcd_dev *smcd;
>   	struct device dev;
>   	u16 chid;
>   	struct smcd_gid local_gid;
> +	DECLARE_BITMAP(sba_idx_mask, SMC_LODEV_MAX_DMBS);
> +	rwlock_t dmb_ht_lock;
> +	DECLARE_HASHTABLE(dmb_ht, SMC_LODEV_DMBS_HASH_BITS);
>   };
>   
>   int smc_loopback_init(void);