diff mbox series

[net,v3] octeontx2-pf: Fix page pool cache index corruption.

Message ID 20230908025309.45096-1-rkannoth@marvell.com (mailing list archive)
State Accepted
Commit 88e69af061f2e061a68751ef9cad47a674527a1b
Delegated to: Netdev Maintainers
Headers show
Series [net,v3] octeontx2-pf: Fix page pool cache index corruption. | expand

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netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/build_clang success Errors and warnings before: 1353 this patch: 1353
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1365 this patch: 1365
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 199 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Ratheesh Kannoth Sept. 8, 2023, 2:53 a.m. UTC
The access to page pool `cache' array and the `count' variable
is not locked. Page pool cache access is fine as long as there
is only one consumer per pool.

octeontx2 driver fills in rx buffers from page pool in NAPI context.
If system is stressed and could not allocate buffers, refiiling work
will be delegated to a delayed workqueue. This means that there are
two cosumers to the page pool cache.

Either workqueue or IRQ/NAPI can be run on other CPU. This will lead
to lock less access, hence corruption of cache pool indexes.

To fix this issue, NAPI is rescheduled from workqueue context to refill
rx buffers.

Fixes: b2e3406a38f0 ("octeontx2-pf: Add support for page pool")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>

---
ChangeLogs
v2 -> v3: Reverse xmas tree fixes for local variables.
v1 -> v2: Added local_bh_disable() to be precise on napi scheduling.

v0 -> v1: udelay will waste CPU cycles in UP. So call napi_schedule from
	  delayed work queue context.

---
---
 .../ethernet/marvell/octeontx2/nic/cn10k.c    |  6 ++-
 .../ethernet/marvell/octeontx2/nic/cn10k.h    |  2 +-
 .../marvell/octeontx2/nic/otx2_common.c       | 43 +++----------------
 .../marvell/octeontx2/nic/otx2_common.h       |  3 +-
 .../ethernet/marvell/octeontx2/nic/otx2_pf.c  |  7 +--
 .../marvell/octeontx2/nic/otx2_txrx.c         | 30 ++++++++++---
 .../marvell/octeontx2/nic/otx2_txrx.h         |  4 +-
 7 files changed, 44 insertions(+), 51 deletions(-)

Comments

Sebastian Andrzej Siewior Sept. 8, 2023, 11:02 a.m. UTC | #1
On 2023-09-08 08:23:09 [+0530], Ratheesh Kannoth wrote:
> Fixes: b2e3406a38f0 ("octeontx2-pf: Add support for page pool")
> Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

You keep loosing these :)

Sebastian
patchwork-bot+netdevbpf@kernel.org Sept. 10, 2023, 6:30 p.m. UTC | #2
Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Fri, 8 Sep 2023 08:23:09 +0530 you wrote:
> The access to page pool `cache' array and the `count' variable
> is not locked. Page pool cache access is fine as long as there
> is only one consumer per pool.
> 
> octeontx2 driver fills in rx buffers from page pool in NAPI context.
> If system is stressed and could not allocate buffers, refiiling work
> will be delegated to a delayed workqueue. This means that there are
> two cosumers to the page pool cache.
> 
> [...]

Here is the summary with links:
  - [net,v3] octeontx2-pf: Fix page pool cache index corruption.
    https://git.kernel.org/netdev/net/c/88e69af061f2

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.c b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.c
index 826f691de259..a4a258da8dd5 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.c
@@ -107,12 +107,13 @@  int cn10k_sq_aq_init(void *dev, u16 qidx, u16 sqb_aura)
 }
 
 #define NPA_MAX_BURST 16
-void cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq)
+int cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq)
 {
 	struct otx2_nic *pfvf = dev;
+	int cnt = cq->pool_ptrs;
 	u64 ptrs[NPA_MAX_BURST];
-	int num_ptrs = 1;
 	dma_addr_t bufptr;
+	int num_ptrs = 1;
 
 	/* Refill pool with new buffers */
 	while (cq->pool_ptrs) {
@@ -131,6 +132,7 @@  void cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq)
 			num_ptrs = 1;
 		}
 	}
+	return cnt - cq->pool_ptrs;
 }
 
 void cn10k_sqe_flush(void *dev, struct otx2_snd_queue *sq, int size, int qidx)
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.h b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.h
index 8ae96815865e..c1861f7de254 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k.h
@@ -24,7 +24,7 @@  static inline int mtu_to_dwrr_weight(struct otx2_nic *pfvf, int mtu)
 	return weight;
 }
 
-void cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq);
+int cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq);
 void cn10k_sqe_flush(void *dev, struct otx2_snd_queue *sq, int size, int qidx);
 int cn10k_sq_aq_init(void *dev, u16 qidx, u16 sqb_aura);
 int cn10k_lmtst_init(struct otx2_nic *pfvf);
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index 8511906cb4e2..997fedac3a98 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -574,20 +574,8 @@  int otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
 int otx2_alloc_buffer(struct otx2_nic *pfvf, struct otx2_cq_queue *cq,
 		      dma_addr_t *dma)
 {
-	if (unlikely(__otx2_alloc_rbuf(pfvf, cq->rbpool, dma))) {
-		struct refill_work *work;
-		struct delayed_work *dwork;
-
-		work = &pfvf->refill_wrk[cq->cq_idx];
-		dwork = &work->pool_refill_work;
-		/* Schedule a task if no other task is running */
-		if (!cq->refill_task_sched) {
-			cq->refill_task_sched = true;
-			schedule_delayed_work(dwork,
-					      msecs_to_jiffies(100));
-		}
+	if (unlikely(__otx2_alloc_rbuf(pfvf, cq->rbpool, dma)))
 		return -ENOMEM;
-	}
 	return 0;
 }
 
@@ -1082,39 +1070,20 @@  static int otx2_cq_init(struct otx2_nic *pfvf, u16 qidx)
 static void otx2_pool_refill_task(struct work_struct *work)
 {
 	struct otx2_cq_queue *cq;
-	struct otx2_pool *rbpool;
 	struct refill_work *wrk;
-	int qidx, free_ptrs = 0;
 	struct otx2_nic *pfvf;
-	dma_addr_t bufptr;
+	int qidx;
 
 	wrk = container_of(work, struct refill_work, pool_refill_work.work);
 	pfvf = wrk->pf;
 	qidx = wrk - pfvf->refill_wrk;
 	cq = &pfvf->qset.cq[qidx];
-	rbpool = cq->rbpool;
-	free_ptrs = cq->pool_ptrs;
 
-	while (cq->pool_ptrs) {
-		if (otx2_alloc_rbuf(pfvf, rbpool, &bufptr)) {
-			/* Schedule a WQ if we fails to free atleast half of the
-			 * pointers else enable napi for this RQ.
-			 */
-			if (!((free_ptrs - cq->pool_ptrs) > free_ptrs / 2)) {
-				struct delayed_work *dwork;
-
-				dwork = &wrk->pool_refill_work;
-				schedule_delayed_work(dwork,
-						      msecs_to_jiffies(100));
-			} else {
-				cq->refill_task_sched = false;
-			}
-			return;
-		}
-		pfvf->hw_ops->aura_freeptr(pfvf, qidx, bufptr + OTX2_HEAD_ROOM);
-		cq->pool_ptrs--;
-	}
 	cq->refill_task_sched = false;
+
+	local_bh_disable();
+	napi_schedule(wrk->napi);
+	local_bh_enable();
 }
 
 int otx2_config_nix_queues(struct otx2_nic *pfvf)
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
index 4c6032ee7800..c04a8ee53a82 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
@@ -302,6 +302,7 @@  struct flr_work {
 struct refill_work {
 	struct delayed_work pool_refill_work;
 	struct otx2_nic *pf;
+	struct napi_struct *napi;
 };
 
 /* PTPv2 originTimestamp structure */
@@ -370,7 +371,7 @@  struct dev_hw_ops {
 	int	(*sq_aq_init)(void *dev, u16 qidx, u16 sqb_aura);
 	void	(*sqe_flush)(void *dev, struct otx2_snd_queue *sq,
 			     int size, int qidx);
-	void	(*refill_pool_ptrs)(void *dev, struct otx2_cq_queue *cq);
+	int	(*refill_pool_ptrs)(void *dev, struct otx2_cq_queue *cq);
 	void	(*aura_freeptr)(void *dev, int aura, u64 buf);
 };
 
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
index 70b9065f7d10..6daf4d58c25d 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
@@ -1943,6 +1943,10 @@  int otx2_stop(struct net_device *netdev)
 
 	netif_tx_disable(netdev);
 
+	for (wrk = 0; wrk < pf->qset.cq_cnt; wrk++)
+		cancel_delayed_work_sync(&pf->refill_wrk[wrk].pool_refill_work);
+	devm_kfree(pf->dev, pf->refill_wrk);
+
 	otx2_free_hw_resources(pf);
 	otx2_free_cints(pf, pf->hw.cint_cnt);
 	otx2_disable_napi(pf);
@@ -1950,9 +1954,6 @@  int otx2_stop(struct net_device *netdev)
 	for (qidx = 0; qidx < netdev->num_tx_queues; qidx++)
 		netdev_tx_reset_queue(netdev_get_tx_queue(netdev, qidx));
 
-	for (wrk = 0; wrk < pf->qset.cq_cnt; wrk++)
-		cancel_delayed_work_sync(&pf->refill_wrk[wrk].pool_refill_work);
-	devm_kfree(pf->dev, pf->refill_wrk);
 
 	kfree(qset->sq);
 	kfree(qset->cq);
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
index e369baf11530..e77d43848955 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c
@@ -424,9 +424,10 @@  static int otx2_rx_napi_handler(struct otx2_nic *pfvf,
 	return processed_cqe;
 }
 
-void otx2_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq)
+int otx2_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq)
 {
 	struct otx2_nic *pfvf = dev;
+	int cnt = cq->pool_ptrs;
 	dma_addr_t bufptr;
 
 	while (cq->pool_ptrs) {
@@ -435,6 +436,8 @@  void otx2_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq)
 		otx2_aura_freeptr(pfvf, cq->cq_idx, bufptr + OTX2_HEAD_ROOM);
 		cq->pool_ptrs--;
 	}
+
+	return cnt - cq->pool_ptrs;
 }
 
 static int otx2_tx_napi_handler(struct otx2_nic *pfvf,
@@ -521,6 +524,7 @@  int otx2_napi_handler(struct napi_struct *napi, int budget)
 	struct otx2_cq_queue *cq;
 	struct otx2_qset *qset;
 	struct otx2_nic *pfvf;
+	int filled_cnt = -1;
 
 	cq_poll = container_of(napi, struct otx2_cq_poll, napi);
 	pfvf = (struct otx2_nic *)cq_poll->dev;
@@ -541,7 +545,7 @@  int otx2_napi_handler(struct napi_struct *napi, int budget)
 	}
 
 	if (rx_cq && rx_cq->pool_ptrs)
-		pfvf->hw_ops->refill_pool_ptrs(pfvf, rx_cq);
+		filled_cnt = pfvf->hw_ops->refill_pool_ptrs(pfvf, rx_cq);
 	/* Clear the IRQ */
 	otx2_write64(pfvf, NIX_LF_CINTX_INT(cq_poll->cint_idx), BIT_ULL(0));
 
@@ -561,9 +565,25 @@  int otx2_napi_handler(struct napi_struct *napi, int budget)
 				otx2_config_irq_coalescing(pfvf, i);
 		}
 
-		/* Re-enable interrupts */
-		otx2_write64(pfvf, NIX_LF_CINTX_ENA_W1S(cq_poll->cint_idx),
-			     BIT_ULL(0));
+		if (unlikely(!filled_cnt)) {
+			struct refill_work *work;
+			struct delayed_work *dwork;
+
+			work = &pfvf->refill_wrk[cq->cq_idx];
+			dwork = &work->pool_refill_work;
+			/* Schedule a task if no other task is running */
+			if (!cq->refill_task_sched) {
+				work->napi = napi;
+				cq->refill_task_sched = true;
+				schedule_delayed_work(dwork,
+						      msecs_to_jiffies(100));
+			}
+		} else {
+			/* Re-enable interrupts */
+			otx2_write64(pfvf,
+				     NIX_LF_CINTX_ENA_W1S(cq_poll->cint_idx),
+				     BIT_ULL(0));
+		}
 	}
 	return workdone;
 }
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.h
index 9e3bfbe5c480..a82ffca8ce1b 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.h
@@ -170,6 +170,6 @@  void cn10k_sqe_flush(void *dev, struct otx2_snd_queue *sq,
 		     int size, int qidx);
 void otx2_sqe_flush(void *dev, struct otx2_snd_queue *sq,
 		    int size, int qidx);
-void otx2_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq);
-void cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq);
+int otx2_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq);
+int cn10k_refill_pool_ptrs(void *dev, struct otx2_cq_queue *cq);
 #endif /* OTX2_TXRX_H */