target/linux/generic/backport-6.1/770-net-introduce-napi_is_scheduled-helper.patch

   1 From 7f3eb2174512fe6c9c0f062e96eccb0d3cc6d5cd Mon Sep 17 00:00:00 2001
   2 From: Christian Marangi <ansuelsmth@gmail.com>
   3 Date: Wed, 18 Oct 2023 14:35:47 +0200
   4 Subject: [PATCH] net: introduce napi_is_scheduled helper
   5
   6 We currently have napi_if_scheduled_mark_missed that can be used to
   7 check if napi is scheduled but that does more thing than simply checking
   8 it and return a bool. Some driver already implement custom function to
   9 check if napi is scheduled.
  10
  11 Drop these custom function and introduce napi_is_scheduled that simply
  12 check if napi is scheduled atomically.
  13
  14 Update any driver and code that implement a similar check and instead
  15 use this new helper.
  16
  17 Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
  18 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
  19 ---
  20  drivers/net/ethernet/chelsio/cxgb3/sge.c  |  8 --------
  21  drivers/net/wireless/realtek/rtw89/core.c |  2 +-
  22  include/linux/netdevice.h                 | 23 +++++++++++++++++++++++
  23  net/core/dev.c                            |  2 +-
  24  4 files changed, 25 insertions(+), 10 deletions(-)
  25
  26 --- a/drivers/net/ethernet/chelsio/cxgb3/sge.c
  27 +++ b/drivers/net/ethernet/chelsio/cxgb3/sge.c
  28 @@ -2507,14 +2507,6 @@ static int napi_rx_handler(struct napi_s
  29         return work_done;
  30  }
  31
  32 -/*
  33 - * Returns true if the device is already scheduled for polling.
  34 - */
  35 -static inline int napi_is_scheduled(struct napi_struct *napi)
  36 -{
  37 -       return test_bit(NAPI_STATE_SCHED, &napi->state);
  38 -}
  39 -
  40  /**
  41   *     process_pure_responses - process pure responses from a response queue
  42   *     @adap: the adapter
  43 --- a/drivers/net/wireless/realtek/rtw89/core.c
  44 +++ b/drivers/net/wireless/realtek/rtw89/core.c
  45 @@ -1479,7 +1479,7 @@ static void rtw89_core_rx_to_mac80211(st
  46         struct napi_struct *napi = &rtwdev->napi;
  47
  48         /* In low power mode, napi isn't scheduled. Receive it to netif. */
  49 -       if (unlikely(!test_bit(NAPI_STATE_SCHED, &napi->state)))
  50 +       if (unlikely(!napi_is_scheduled(napi)))
  51                 napi = NULL;
  52
  53         rtw89_core_hw_to_sband_rate(rx_status);
  54 --- a/include/linux/netdevice.h
  55 +++ b/include/linux/netdevice.h
  56 @@ -468,6 +468,29 @@ static inline bool napi_prefer_busy_poll
  57         return test_bit(NAPI_STATE_PREFER_BUSY_POLL, &n->state);
  58  }
  59
  60 +/**
  61 + * napi_is_scheduled - test if NAPI is scheduled
  62 + * @n: NAPI context
  63 + *
  64 + * This check is "best-effort". With no locking implemented,
  65 + * a NAPI can be scheduled or terminate right after this check
  66 + * and produce not precise results.
  67 + *
  68 + * NAPI_STATE_SCHED is an internal state, napi_is_scheduled
  69 + * should not be used normally and napi_schedule should be
  70 + * used instead.
  71 + *
  72 + * Use only if the driver really needs to check if a NAPI
  73 + * is scheduled for example in the context of delayed timer
  74 + * that can be skipped if a NAPI is already scheduled.
  75 + *
  76 + * Return True if NAPI is scheduled, False otherwise.
  77 + */
  78 +static inline bool napi_is_scheduled(struct napi_struct *n)
  79 +{
  80 +       return test_bit(NAPI_STATE_SCHED, &n->state);
  81 +}
  82 +
  83  bool napi_schedule_prep(struct napi_struct *n);
  84
  85  /**
  86 --- a/net/core/dev.c
  87 +++ b/net/core/dev.c
  88 @@ -6533,7 +6533,7 @@ static int __napi_poll(struct napi_struc
  89          * accidentally calling ->poll() when NAPI is not scheduled.
  90          */
  91         work = 0;
  92 -       if (test_bit(NAPI_STATE_SCHED, &n->state)) {
  93 +       if (napi_is_scheduled(n)) {
  94                 work = n->poll(n, weight);
  95                 trace_napi_poll(n, work, weight);
  96         }