Re: [RFC PATCH net-next v4 05/11] net/smc: implement DMB-related operations of loopback-ism
From: Wen Gu
Date: Fri Mar 22 2024 - 08:30:28 EST
On 2024/3/21 16:12, Jan Karcher wrote:
On 17/03/2024 11:05, Wen Gu wrote:
This implements DMB (un)registration and data move operations of
loopback-ism device.
Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
---
net/smc/smc_loopback.c | 131 ++++++++++++++++++++++++++++++++++++++++-
net/smc/smc_loopback.h | 13 ++++
2 files changed, 141 insertions(+), 3 deletions(-)
diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
index 253128c77208..7335acb03920 100644
--- a/net/smc/smc_loopback.c
+++ b/net/smc/smc_loopback.c
@@ -15,11 +15,13 @@
#include <linux/types.h>
#include <net/smc.h>
+#include "smc_cdc.h"
#include "smc_ism.h"
#include "smc_loopback.h"
#if IS_ENABLED(CONFIG_SMC_LO)
#define SMC_LO_V2_CAPABLE 0x1 /* loopback-ism acts as ISMv2 */
+#define SMC_DMA_ADDR_INVALID (~(dma_addr_t)0)
static const char smc_lo_dev_name[] = "loopback-ism";
static struct smc_lo_dev *lo_dev;
@@ -49,6 +51,93 @@ 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_LO_MAX_DMBS) {
+ if (!test_and_set_bit(sba_idx, ldev->sba_idx_mask))
+ break;
+ }
+ if (sba_idx == SMC_LO_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->len = dmb->dmb_len;
+ dmb_node->cpu_addr = kzalloc(dmb_node->len, GFP_KERNEL |
+ __GFP_NOWARN | __GFP_NORETRY |
+ __GFP_NOMEMALLOC);
+ if (!dmb_node->cpu_addr) {
+ rc = -ENOMEM;
+ goto err_node;
+ }
+ dmb_node->dma_addr = SMC_DMA_ADDR_INVALID;
+
+again:
+ /* add new dmb into hash table */
+ get_random_bytes(&dmb_node->token, sizeof(dmb_node->token));
+ write_lock_bh(&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_bh(&ldev->dmb_ht_lock);
+ goto again;
+ }
+ }
+ hash_add(ldev->dmb_ht, &dmb_node->list, dmb_node->token);
+ write_unlock_bh(&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_bh(&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_bh(&ldev->dmb_ht_lock);
+ return -EINVAL;
+ }
+ hash_del(&dmb_node->list);
+ write_unlock_bh(&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;
@@ -75,6 +164,40 @@ 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_bh(&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_bh(&ldev->dmb_ht_lock);
+ return -EINVAL;
+ }
+ read_unlock_bh(&ldev->dmb_ht_lock);
+
+ memcpy((char *)rmb_node->cpu_addr + offset, data, size);
Hi Wen Gu,
Could we get into use after free trouble here if the dmb gets unregistered between the read_unlock and memcpy?
rmb_node won't be unregistered until smc_lgr_free_bufs() in __smc_lgr_free(). At
that time, the connections on this lgr should be all freed (smc_conn_free() and
then lgr->refcnt == 0), so I think there will be no move data operation at that
point. But in case there is something unforeseen, I will put memcpy between dmb_ht_lock.
Thanks!
+
+ if (sf) {
+ struct smc_connection *conn =
+ smcd->conn[rmb_node->sba_idx];
Please put the `struct smc_connection *conn = NULL` at the top of the function and assign the value here.
OK, I will put it at the top. Thanks!
Thanks
- Jan
+
+ if (conn && !conn->killed)
+ tasklet_schedule(&conn->rx_tsklet);
+ else
+ return -EPIPE;
+ }
+ return 0;
+}
+
static int smc_lo_supports_v2(void)
{
return SMC_LO_V2_CAPABLE;
@@ -101,14 +224,14 @@ 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_local_gid = smc_lo_get_local_gid,
.get_chid = smc_lo_get_chid,
@@ -173,6 +296,8 @@ static void smcd_lo_unregister_dev(struct smc_lo_dev *ldev)
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 55b41133a97f..24ab9d747613 100644
--- a/net/smc/smc_loopback.h
+++ b/net/smc/smc_loopback.h
@@ -20,13 +20,26 @@
#if IS_ENABLED(CONFIG_SMC_LO)
#define SMC_LO_MAX_DMBS 5000
+#define SMC_LO_DMBS_HASH_BITS 12
#define SMC_LO_CHID 0xFFFF
+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;
+ rwlock_t dmb_ht_lock;
+ DECLARE_BITMAP(sba_idx_mask, SMC_LO_MAX_DMBS);
+ DECLARE_HASHTABLE(dmb_ht, SMC_LO_DMBS_HASH_BITS);
};
#endif