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net: make napi_disable() symmetric with enable
Commit 3765996e4f
("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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
930dfa5631
commit
719c571970
1 changed files with 12 additions and 6 deletions
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@ -6900,19 +6900,25 @@ EXPORT_SYMBOL(netif_napi_add);
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void napi_disable(struct napi_struct *n)
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void napi_disable(struct napi_struct *n)
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{
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{
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unsigned long val, new;
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might_sleep();
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might_sleep();
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set_bit(NAPI_STATE_DISABLE, &n->state);
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set_bit(NAPI_STATE_DISABLE, &n->state);
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while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
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do {
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msleep(1);
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val = READ_ONCE(n->state);
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while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
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if (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)) {
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msleep(1);
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usleep_range(20, 200);
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continue;
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}
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new = val | NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC;
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new &= ~(NAPIF_STATE_THREADED | NAPIF_STATE_PREFER_BUSY_POLL);
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} while (cmpxchg(&n->state, val, new) != val);
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hrtimer_cancel(&n->timer);
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hrtimer_cancel(&n->timer);
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clear_bit(NAPI_STATE_PREFER_BUSY_POLL, &n->state);
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clear_bit(NAPI_STATE_DISABLE, &n->state);
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clear_bit(NAPI_STATE_DISABLE, &n->state);
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clear_bit(NAPI_STATE_THREADED, &n->state);
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}
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}
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EXPORT_SYMBOL(napi_disable);
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EXPORT_SYMBOL(napi_disable);
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