target/linux/generic/backport-5.10/600-v5.12-net-extract-napi-poll-functionality-to-__napi_poll.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Mon, 8 Feb 2021 11:34:08 -0800
   3 Subject: [PATCH] net: extract napi poll functionality to __napi_poll()
   4
   5 This commit introduces a new function __napi_poll() which does the main
   6 logic of the existing napi_poll() function, and will be called by other
   7 functions in later commits.
   8 This idea and implementation is done by Felix Fietkau <nbd@nbd.name> and
   9 is proposed as part of the patch to move napi work to work_queue
  10 context.
  11 This commit by itself is a code restructure.
  12
  13 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  14 Signed-off-by: Wei Wang <weiwan@google.com>
  15 Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
  16 Signed-off-by: David S. Miller <davem@davemloft.net>
  17 ---
  18
  19 --- a/net/core/dev.c
  20 +++ b/net/core/dev.c
  21 @@ -6752,15 +6752,10 @@ void __netif_napi_del(struct napi_struct
  22  }
  23  EXPORT_SYMBOL(__netif_napi_del);
  24
  25 -static int napi_poll(struct napi_struct *n, struct list_head *repoll)
  26 +static int __napi_poll(struct napi_struct *n, bool *repoll)
  27  {
  28 -       void *have;
  29         int work, weight;
  30
  31 -       list_del_init(&n->poll_list);
  32 -
  33 -       have = netpoll_poll_lock(n);
  34 -
  35         weight = n->weight;
  36
  37         /* This NAPI_STATE_SCHED test is for avoiding a race
  38 @@ -6780,7 +6775,7 @@ static int napi_poll(struct napi_struct
  39                             n->poll, work, weight);
  40
  41         if (likely(work < weight))
  42 -               goto out_unlock;
  43 +               return work;
  44
  45         /* Drivers must not modify the NAPI state if they
  46          * consume the entire weight.  In such cases this code
  47 @@ -6789,7 +6784,7 @@ static int napi_poll(struct napi_struct
  48          */
  49         if (unlikely(napi_disable_pending(n))) {
  50                 napi_complete(n);
  51 -               goto out_unlock;
  52 +               return work;
  53         }
  54
  55         if (n->gro_bitmask) {
  56 @@ -6807,12 +6802,29 @@ static int napi_poll(struct napi_struct
  57         if (unlikely(!list_empty(&n->poll_list))) {
  58                 pr_warn_once("%s: Budget exhausted after napi rescheduled\n",
  59                              n->dev ? n->dev->name : "backlog");
  60 -               goto out_unlock;
  61 +               return work;
  62         }
  63
  64 -       list_add_tail(&n->poll_list, repoll);
  65 +       *repoll = true;
  66 +
  67 +       return work;
  68 +}
  69 +
  70 +static int napi_poll(struct napi_struct *n, struct list_head *repoll)
  71 +{
  72 +       bool do_repoll = false;
  73 +       void *have;
  74 +       int work;
  75 +
  76 +       list_del_init(&n->poll_list);
  77 +
  78 +       have = netpoll_poll_lock(n);
  79 +
  80 +       work = __napi_poll(n, &do_repoll);
  81 +
  82 +       if (do_repoll)
  83 +               list_add_tail(&n->poll_list, repoll);
  84
  85 -out_unlock:
  86         netpoll_poll_unlock(have);
  87
  88         return work;