[][Backport napi releated bug fixes to openwrt 21.02]
[Description]
Add some napi releated bug fixeds to openwrt 21.02
Please refer to following patches for detail:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/core/dev.c?id=0315a075f1343966ea2d9a085666a88a69ea6a3d
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/core/dev.c?id=3765996e4f0b8a755cab215a08df744490c76052
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/core/dev.c?id=719c571970109b0d0af24745d31b202affc9365f
Please notice following changed:
+ new &= ~(NAPIF_STATE_THREADED | NAPIF_STATE_PREFER_BUSY_POLL);
/* No "NAPIF_STATE_PREFER_BUSY_POLL" in kernel 5.4 */
- clear_bit(NAPI_STATE_PREFER_BUSY_POLL, &n->state);
Test: Build PASS
[Release-log]
N/A
Change-Id: Icb0d352821fb91108eb08f46f8bda8f1419f7777
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6050622
diff --git a/target/linux/mediatek/patches-5.4/7001-net-make-napi-disable-symmetric-with-enable.patch b/target/linux/mediatek/patches-5.4/7001-net-make-napi-disable-symmetric-with-enable.patch
new file mode 100644
index 0000000..ac84ffc
--- /dev/null
+++ b/target/linux/mediatek/patches-5.4/7001-net-make-napi-disable-symmetric-with-enable.patch
@@ -0,0 +1,64 @@
+From git@z Thu Jan 1 00:00:00 1970
+Subject: [PATCH v2] net: make napi_disable() symmetric with enable
+From: Jakub Kicinski <kuba@kernel.org>
+Date: Fri, 24 Sep 2021 13:24:53 -0700
+Message-Id: <20210924202453.1051687-1-kuba@kernel.org>
+To: davem@davemloft.net
+Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, weiwan@google.com, xuanzhuo@linux.alibaba.com, Jakub Kicinski <kuba@kernel.org>
+List-Id: <netdev.vger.kernel.org>
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+Commit 3765996e4f0b ("napi: fix race inside napi_enable") fixed
+an ordering bug in napi_enable() and made the napi_enable() diverge
+from napi_disable(). The state transitions done on disable are
+not symmetric to enable.
+
+There is no known bug in napi_disable() this is just refactoring.
+
+Eric suggests we can also replace msleep(1) with a more opportunistic
+usleep_range().
+
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ net/core/dev.c | 17 ++++++++++++-----
+ 1 file changed, 12 insertions(+), 5 deletions(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index f24c3a9..f0a556a 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -6386,18 +6386,25 @@ EXPORT_SYMBOL(netif_napi_add);
+
+ void napi_disable(struct napi_struct *n)
+ {
++ unsigned long val, new;
++
+ might_sleep();
+ set_bit(NAPI_STATE_DISABLE, &n->state);
+
+- while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
+- msleep(1);
+- while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
+- msleep(1);
++ do {
++ val = READ_ONCE(n->state);
++ if (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)) {
++ usleep_range(20, 200);
++ continue;
++ }
++
++ new = val | NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC;
++ new &= ~(NAPIF_STATE_THREADED);
++ } while (cmpxchg(&n->state, val, new) != val);
+
+ hrtimer_cancel(&n->timer);
+
+ clear_bit(NAPI_STATE_DISABLE, &n->state);
+- clear_bit(NAPI_STATE_THREADED, &n->state);
+ }
+ EXPORT_SYMBOL(napi_disable);
+
+--
+2.31.1