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net/smc: Stop the CLC flow if no link to map buffers on 

There might be a potential race between SMC-R buffer map and
link group termination.

smc_smcr_terminate_all()     | smc_connect_rdma()
--------------------------------------------------------------
                             | smc_conn_create()
for links in smcibdev        |
        schedule links down  |
                             | smc_buf_create()
                             |  \- smcr_buf_map_usable_links()
                             |      \- no usable links found,
                             |         (rmb->mr = NULL)
                             |
                             | smc_clc_send_confirm()
                             |  \- access conn->rmb_desc->mr[]->rkey
                             |     (panic)

During reboot and IB device module remove, all links will be set
down and no usable links remain in link groups. In such situation
smcr_buf_map_usable_links() should return an error and stop the
CLC flow accessing to uninitialized mr.

Fixes: b9247544c1 ("net/smc: convert static link ID instances to support multiple links")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Link: https://lore.kernel.org/r/1663656189-32090-1-git-send-email-guwen@linux.alibaba.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Wen Gu 2022-09-20 14:43:09 +08:00 committed by Paolo Abeni
parent 624aea6bed
commit e738455b2c
1 changed files with 4 additions and 1 deletions
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5
net/smc/smc_core.c
View File

@ -2239,7 +2239,7 @@ out:
static int smcr_buf_map_usable_links(struct smc_link_group *lgr,
struct smc_buf_desc *buf_desc, bool is_rmb)
{
int i, rc = 0;
int i, rc = 0, cnt = 0;
/* protect against parallel link reconfiguration */
mutex_lock(&lgr->llc_conf_mutex);
@ -2252,9 +2252,12 @@ static int smcr_buf_map_usable_links(struct smc_link_group *lgr,
rc = -ENOMEM;
goto out;
}
cnt++;
}
out:
mutex_unlock(&lgr->llc_conf_mutex);
if (!rc && !cnt)
rc = -EINVAL;
return rc;
}