Commit 4351ca3f authored by Håkon Bugge's avatar Håkon Bugge Committed by Jakub Kicinski
Browse files

rds: ib: Increment i_fastreg_wrs before bailing out 



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: 1659185f ("RDS: IB: Support Fastreg MR (FRMR) memory registration mode")
Fixes: 3a2886cc ("net/rds: Keep track of and wait for FRWR segments in use upon shutdown")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarHåkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: default avatarAllison Henderson <allison.henderson@oracle.com>
Link: https://patch.msgid.link/20250911133336.451212-1-haakon.bugge@oracle.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2e5fb2ff

net/rds/ib_frmr.c

+12 −8
Original line number Diff line number Diff line
@@ -133,12 +133,15 @@ static int rds_ib_post_reg_frmr(struct rds_ib_mr *ibmr) 


	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 rds_ib_mr *ibmr) 
		/* 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 rds_ib_mr *ibmr) 
	 */

	wait_event(frmr->fr_reg_done, !frmr->fr_reg);



out:

	return ret;



out_inc:

	atomic_inc(&ibmr->ic->i_fastreg_wrs);

	return ret;

}