6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Håkon Bugge haakon.bugge@oracle.com
commit 4351ca3fcb3ffecf12631b4996bf085a2dad0db6 upstream.
We need to increment i_fastreg_wrs before we bail out from rds_ib_post_reg_frmr().
We have a fixed budget of how many FRWR operations that can be outstanding using the dedicated QP used for memory registrations and de-registrations. This budget is enforced by the atomic_t i_fastreg_wrs. If we bail out early in rds_ib_post_reg_frmr(), we will "leak" the possibility of posting an FRWR operation, and if that accumulates, no FRWR operation can be carried out.
Fixes: 1659185fb4d0 ("RDS: IB: Support Fastreg MR (FRMR) memory registration mode") Fixes: 3a2886cca703 ("net/rds: Keep track of and wait for FRWR segments in use upon shutdown") Cc: stable@vger.kernel.org Signed-off-by: Håkon Bugge haakon.bugge@oracle.com Reviewed-by: Allison Henderson allison.henderson@oracle.com Link: https://patch.msgid.link/20250911133336.451212-1-haakon.bugge@oracle.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/rds/ib_frmr.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-)
--- a/net/rds/ib_frmr.c +++ b/net/rds/ib_frmr.c @@ -133,12 +133,15 @@ static int rds_ib_post_reg_frmr(struct r
ret = ib_map_mr_sg_zbva(frmr->mr, ibmr->sg, ibmr->sg_dma_len, &off, PAGE_SIZE); - if (unlikely(ret != ibmr->sg_dma_len)) - return ret < 0 ? ret : -EINVAL; + if (unlikely(ret != ibmr->sg_dma_len)) { + ret = ret < 0 ? ret : -EINVAL; + goto out_inc; + }
- if (cmpxchg(&frmr->fr_state, - FRMR_IS_FREE, FRMR_IS_INUSE) != FRMR_IS_FREE) - return -EBUSY; + if (cmpxchg(&frmr->fr_state, FRMR_IS_FREE, FRMR_IS_INUSE) != FRMR_IS_FREE) { + ret = -EBUSY; + goto out_inc; + }
atomic_inc(&ibmr->ic->i_fastreg_inuse_count);
@@ -166,11 +169,10 @@ static int rds_ib_post_reg_frmr(struct r /* Failure here can be because of -ENOMEM as well */ rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
- atomic_inc(&ibmr->ic->i_fastreg_wrs); if (printk_ratelimit()) pr_warn("RDS/IB: %s returned error(%d)\n", __func__, ret); - goto out; + goto out_inc; }
/* Wait for the registration to complete in order to prevent an invalid @@ -179,8 +181,10 @@ static int rds_ib_post_reg_frmr(struct r */ wait_event(frmr->fr_reg_done, !frmr->fr_reg);
-out: + return ret;
+out_inc: + atomic_inc(&ibmr->ic->i_fastreg_wrs); return ret; }