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Subject[PATCH AUTOSEL 5.4 140/350] RDMA/siw: Fix SQ/RQ drain logic
Date
From: Bernard Metzler <bmt@zurich.ibm.com>

[ Upstream commit cf049bb31f7101d9672eaf97ade4fdd5171ddf26 ]

Storage ULPs (e.g. iSER & NVMeOF) use ib_drain_qp() to drain
QP/CQ. Current SIW's own drain routines do not properly wait until all
SQ/RQ elements are completed and reaped from the CQ. This may cause touch
after free issues. New logic relies on generic
__ib_drain_sq()/__ib_drain_rq() posting a final work request, which SIW
immediately flushes to CQ.

Fixes: 303ae1cdfdf7 ("rdma/siw: application interface")
Link: https://lore.kernel.org/r/20191004125356.20673-1-bmt@zurich.ibm.com
Signed-off-by: Krishnamraju Eraparaju <krishna2@chelsio.com>
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/sw/siw/siw_main.c | 20 ----
drivers/infiniband/sw/siw/siw_verbs.c | 144 ++++++++++++++++++++++----
2 files changed, 122 insertions(+), 42 deletions(-)

diff --git a/drivers/infiniband/sw/siw/siw_main.c b/drivers/infiniband/sw/siw/siw_main.c
index 05a92f997f603..fb01407a310fa 100644
--- a/drivers/infiniband/sw/siw/siw_main.c
+++ b/drivers/infiniband/sw/siw/siw_main.c
@@ -248,24 +248,6 @@ static struct ib_qp *siw_get_base_qp(struct ib_device *base_dev, int id)
return NULL;
}

-static void siw_verbs_sq_flush(struct ib_qp *base_qp)
-{
- struct siw_qp *qp = to_siw_qp(base_qp);
-
- down_write(&qp->state_lock);
- siw_sq_flush(qp);
- up_write(&qp->state_lock);
-}
-
-static void siw_verbs_rq_flush(struct ib_qp *base_qp)
-{
- struct siw_qp *qp = to_siw_qp(base_qp);
-
- down_write(&qp->state_lock);
- siw_rq_flush(qp);
- up_write(&qp->state_lock);
-}
-
static const struct ib_device_ops siw_device_ops = {
.owner = THIS_MODULE,
.uverbs_abi_ver = SIW_ABI_VERSION,
@@ -284,8 +266,6 @@ static const struct ib_device_ops siw_device_ops = {
.destroy_cq = siw_destroy_cq,
.destroy_qp = siw_destroy_qp,
.destroy_srq = siw_destroy_srq,
- .drain_rq = siw_verbs_rq_flush,
- .drain_sq = siw_verbs_sq_flush,
.get_dma_mr = siw_get_dma_mr,
.get_port_immutable = siw_get_port_immutable,
.iw_accept = siw_accept,
diff --git a/drivers/infiniband/sw/siw/siw_verbs.c b/drivers/infiniband/sw/siw/siw_verbs.c
index b18a677832e10..7d0a7edc533d1 100644
--- a/drivers/infiniband/sw/siw/siw_verbs.c
+++ b/drivers/infiniband/sw/siw/siw_verbs.c
@@ -685,6 +685,47 @@ static int siw_copy_inline_sgl(const struct ib_send_wr *core_wr,
return bytes;
}

+/* Complete SQ WR's without processing */
+static int siw_sq_flush_wr(struct siw_qp *qp, const struct ib_send_wr *wr,
+ const struct ib_send_wr **bad_wr)
+{
+ struct siw_sqe sqe = {};
+ int rv = 0;
+
+ while (wr) {
+ sqe.id = wr->wr_id;
+ sqe.opcode = wr->opcode;
+ rv = siw_sqe_complete(qp, &sqe, 0, SIW_WC_WR_FLUSH_ERR);
+ if (rv) {
+ if (bad_wr)
+ *bad_wr = wr;
+ break;
+ }
+ wr = wr->next;
+ }
+ return rv;
+}
+
+/* Complete RQ WR's without processing */
+static int siw_rq_flush_wr(struct siw_qp *qp, const struct ib_recv_wr *wr,
+ const struct ib_recv_wr **bad_wr)
+{
+ struct siw_rqe rqe = {};
+ int rv = 0;
+
+ while (wr) {
+ rqe.id = wr->wr_id;
+ rv = siw_rqe_complete(qp, &rqe, 0, 0, SIW_WC_WR_FLUSH_ERR);
+ if (rv) {
+ if (bad_wr)
+ *bad_wr = wr;
+ break;
+ }
+ wr = wr->next;
+ }
+ return rv;
+}
+
/*
* siw_post_send()
*
@@ -703,26 +744,54 @@ int siw_post_send(struct ib_qp *base_qp, const struct ib_send_wr *wr,
unsigned long flags;
int rv = 0;

+ if (wr && !qp->kernel_verbs) {
+ siw_dbg_qp(qp, "wr must be empty for user mapped sq\n");
+ *bad_wr = wr;
+ return -EINVAL;
+ }
+
/*
* Try to acquire QP state lock. Must be non-blocking
* to accommodate kernel clients needs.
*/
if (!down_read_trylock(&qp->state_lock)) {
- *bad_wr = wr;
- siw_dbg_qp(qp, "QP locked, state %d\n", qp->attrs.state);
- return -ENOTCONN;
+ if (qp->attrs.state == SIW_QP_STATE_ERROR) {
+ /*
+ * ERROR state is final, so we can be sure
+ * this state will not change as long as the QP
+ * exists.
+ *
+ * This handles an ib_drain_sq() call with
+ * a concurrent request to set the QP state
+ * to ERROR.
+ */
+ rv = siw_sq_flush_wr(qp, wr, bad_wr);
+ } else {
+ siw_dbg_qp(qp, "QP locked, state %d\n",
+ qp->attrs.state);
+ *bad_wr = wr;
+ rv = -ENOTCONN;
+ }
+ return rv;
}
if (unlikely(qp->attrs.state != SIW_QP_STATE_RTS)) {
+ if (qp->attrs.state == SIW_QP_STATE_ERROR) {
+ /*
+ * Immediately flush this WR to CQ, if QP
+ * is in ERROR state. SQ is guaranteed to
+ * be empty, so WR complets in-order.
+ *
+ * Typically triggered by ib_drain_sq().
+ */
+ rv = siw_sq_flush_wr(qp, wr, bad_wr);
+ } else {
+ siw_dbg_qp(qp, "QP out of state %d\n",
+ qp->attrs.state);
+ *bad_wr = wr;
+ rv = -ENOTCONN;
+ }
up_read(&qp->state_lock);
- *bad_wr = wr;
- siw_dbg_qp(qp, "QP out of state %d\n", qp->attrs.state);
- return -ENOTCONN;
- }
- if (wr && !qp->kernel_verbs) {
- siw_dbg_qp(qp, "wr must be empty for user mapped sq\n");
- up_read(&qp->state_lock);
- *bad_wr = wr;
- return -EINVAL;
+ return rv;
}
spin_lock_irqsave(&qp->sq_lock, flags);

@@ -917,24 +986,55 @@ int siw_post_receive(struct ib_qp *base_qp, const struct ib_recv_wr *wr,
*bad_wr = wr;
return -EOPNOTSUPP; /* what else from errno.h? */
}
- /*
- * Try to acquire QP state lock. Must be non-blocking
- * to accommodate kernel clients needs.
- */
- if (!down_read_trylock(&qp->state_lock)) {
- *bad_wr = wr;
- return -ENOTCONN;
- }
if (!qp->kernel_verbs) {
siw_dbg_qp(qp, "no kernel post_recv for user mapped sq\n");
up_read(&qp->state_lock);
*bad_wr = wr;
return -EINVAL;
}
+
+ /*
+ * Try to acquire QP state lock. Must be non-blocking
+ * to accommodate kernel clients needs.
+ */
+ if (!down_read_trylock(&qp->state_lock)) {
+ if (qp->attrs.state == SIW_QP_STATE_ERROR) {
+ /*
+ * ERROR state is final, so we can be sure
+ * this state will not change as long as the QP
+ * exists.
+ *
+ * This handles an ib_drain_rq() call with
+ * a concurrent request to set the QP state
+ * to ERROR.
+ */
+ rv = siw_rq_flush_wr(qp, wr, bad_wr);
+ } else {
+ siw_dbg_qp(qp, "QP locked, state %d\n",
+ qp->attrs.state);
+ *bad_wr = wr;
+ rv = -ENOTCONN;
+ }
+ return rv;
+ }
if (qp->attrs.state > SIW_QP_STATE_RTS) {
+ if (qp->attrs.state == SIW_QP_STATE_ERROR) {
+ /*
+ * Immediately flush this WR to CQ, if QP
+ * is in ERROR state. RQ is guaranteed to
+ * be empty, so WR complets in-order.
+ *
+ * Typically triggered by ib_drain_rq().
+ */
+ rv = siw_rq_flush_wr(qp, wr, bad_wr);
+ } else {
+ siw_dbg_qp(qp, "QP out of state %d\n",
+ qp->attrs.state);
+ *bad_wr = wr;
+ rv = -ENOTCONN;
+ }
up_read(&qp->state_lock);
- *bad_wr = wr;
- return -EINVAL;
+ return rv;
}
/*
* Serialize potentially multiple producers.
--
2.20.1
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