161 lines
5.1 KiB
Diff
161 lines
5.1 KiB
Diff
From 3420c5bf9d08df074b67c7feda8a37d951d0b232 Mon Sep 17 00:00:00 2001
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From: Ioana Radulescu <ruxandra.radulescu@nxp.com>
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Date: Wed, 18 Sep 2019 13:31:07 +0300
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Subject: [PATCH] dpaa2-eth: Avoid unbounded while loops
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Throughout the driver there are several places where we wait
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indefinitely for DPIO portal commands to be executed, while
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the portal returns a busy response code.
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Even though in theory we are guaranteed the portals become
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available eventually, in practice the QBMan hardware module
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may become unresponsive in various corner cases.
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Make sure we can never get stuck in an infinite while loop
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by adding a retry counter for all portal commands.
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Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
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---
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drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 30 ++++++++++++++++++++----
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drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h | 8 +++++++
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2 files changed, 33 insertions(+), 5 deletions(-)
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--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
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+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
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@@ -221,6 +221,7 @@ static void xdp_release_buf(struct dpaa2
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struct dpaa2_eth_channel *ch,
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dma_addr_t addr)
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{
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+ int retries = 0;
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int err;
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ch->xdp.drop_bufs[ch->xdp.drop_cnt++] = addr;
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@@ -229,8 +230,11 @@ static void xdp_release_buf(struct dpaa2
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while ((err = dpaa2_io_service_release(ch->dpio, priv->bpid,
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ch->xdp.drop_bufs,
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- ch->xdp.drop_cnt)) == -EBUSY)
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+ ch->xdp.drop_cnt)) == -EBUSY) {
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+ if (retries++ >= DPAA2_ETH_SWP_BUSY_RETRIES)
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+ break;
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cpu_relax();
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+ }
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if (err) {
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free_bufs(priv, ch->xdp.drop_bufs, ch->xdp.drop_cnt);
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@@ -458,7 +462,7 @@ static int consume_frames(struct dpaa2_e
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struct dpaa2_eth_fq *fq = NULL;
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struct dpaa2_dq *dq;
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const struct dpaa2_fd *fd;
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- int cleaned = 0;
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+ int cleaned = 0, retries = 0;
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int is_last;
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do {
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@@ -469,6 +473,11 @@ static int consume_frames(struct dpaa2_e
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* the store until we get some sort of valid response
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* token (either a valid frame or an "empty dequeue")
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*/
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+ if (retries++ >= DPAA2_ETH_SWP_BUSY_RETRIES) {
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+ netdev_err_once(priv->net_dev,
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+ "Unable to read a valid dequeue response\n");
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+ return 0;
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+ }
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continue;
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}
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@@ -477,6 +486,7 @@ static int consume_frames(struct dpaa2_e
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fq->consume(priv, ch, fd, fq);
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cleaned++;
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+ retries = 0;
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} while (!is_last);
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if (!cleaned)
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@@ -949,6 +959,7 @@ static int add_bufs(struct dpaa2_eth_pri
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u64 buf_array[DPAA2_ETH_BUFS_PER_CMD];
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struct page *page;
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dma_addr_t addr;
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+ int retries = 0;
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int i, err;
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for (i = 0; i < DPAA2_ETH_BUFS_PER_CMD; i++) {
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@@ -980,8 +991,11 @@ static int add_bufs(struct dpaa2_eth_pri
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release_bufs:
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/* In case the portal is busy, retry until successful */
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while ((err = dpaa2_io_service_release(ch->dpio, bpid,
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- buf_array, i)) == -EBUSY)
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+ buf_array, i)) == -EBUSY) {
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+ if (retries++ >= DPAA2_ETH_SWP_BUSY_RETRIES)
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+ break;
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cpu_relax();
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+ }
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/* If release command failed, clean up and bail out;
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* not much else we can do about it
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@@ -1032,16 +1046,21 @@ static int seed_pool(struct dpaa2_eth_pr
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static void drain_bufs(struct dpaa2_eth_priv *priv, int count)
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{
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u64 buf_array[DPAA2_ETH_BUFS_PER_CMD];
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+ int retries = 0;
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int ret;
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do {
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ret = dpaa2_io_service_acquire(NULL, priv->bpid,
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buf_array, count);
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if (ret < 0) {
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+ if (ret == -EBUSY &&
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+ retries++ >= DPAA2_ETH_SWP_BUSY_RETRIES)
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+ continue;
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netdev_err(priv->net_dev, "dpaa2_io_service_acquire() failed\n");
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return;
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}
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free_bufs(priv, buf_array, ret);
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+ retries = 0;
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} while (ret);
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}
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@@ -1094,7 +1113,7 @@ static int pull_channel(struct dpaa2_eth
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ch->store);
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dequeues++;
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cpu_relax();
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- } while (err == -EBUSY);
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+ } while (err == -EBUSY && dequeues < DPAA2_ETH_SWP_BUSY_RETRIES);
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ch->stats.dequeue_portal_busy += dequeues;
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if (unlikely(err))
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@@ -1118,6 +1137,7 @@ static int dpaa2_eth_poll(struct napi_st
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struct netdev_queue *nq;
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int store_cleaned, work_done;
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struct list_head rx_list;
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+ int retries = 0;
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int err;
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ch = container_of(napi, struct dpaa2_eth_channel, napi);
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@@ -1163,7 +1183,7 @@ static int dpaa2_eth_poll(struct napi_st
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do {
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err = dpaa2_io_service_rearm(ch->dpio, &ch->nctx);
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cpu_relax();
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- } while (err == -EBUSY);
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+ } while (err == -EBUSY && retries++ < DPAA2_ETH_SWP_BUSY_RETRIES);
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WARN_ONCE(err, "CDAN notifications rearm failed on core %d",
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ch->nctx.desired_cpu);
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--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
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+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
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@@ -245,6 +245,14 @@ static inline struct dpaa2_faead *dpaa2_
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*/
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#define DPAA2_ETH_ENQUEUE_RETRIES 10
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+/* Number of times to retry DPIO portal operations while waiting
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+ * for portal to finish executing current command and become
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+ * available. We want to avoid being stuck in a while loop in case
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+ * hardware becomes unresponsive, but not give up too easily if
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+ * the portal really is busy for valid reasons
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+ */
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+#define DPAA2_ETH_SWP_BUSY_RETRIES 1000
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+
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/* Driver statistics, other than those in struct rtnl_link_stats64.
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* These are usually collected per-CPU and aggregated by ethtool.
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*/
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