Commit 7e417a66 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: napi: use READ_ONCE()/WRITE_ONCE() 



gro_flush_timeout and napi_defer_hard_irqs can be read
from napi_complete_done() while other cpus write the value,
whithout explicit synchronization.

Use READ_ONCE()/WRITE_ONCE() to annotate the races.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6f8b12d6

net/core/dev.c

+3 −3
Original line number Diff line number Diff line
@@ -6242,12 +6242,12 @@ bool napi_complete_done(struct napi_struct *n, int work_done) 


	if (work_done) {

		if (n->gro_bitmask)

			timeout = n->dev->gro_flush_timeout;

		n->defer_hard_irqs_count = n->dev->napi_defer_hard_irqs;

			timeout = READ_ONCE(n->dev->gro_flush_timeout);

		n->defer_hard_irqs_count = READ_ONCE(n->dev->napi_defer_hard_irqs);

	}

	if (n->defer_hard_irqs_count > 0) {

		n->defer_hard_irqs_count--;

		timeout = n->dev->gro_flush_timeout;

		timeout = READ_ONCE(n->dev->gro_flush_timeout);

		if (timeout)

			ret = false;

	}

net/core/net-sysfs.c

+2 −2
Original line number Diff line number Diff line
@@ -367,7 +367,7 @@ NETDEVICE_SHOW_RW(tx_queue_len, fmt_dec); 


static int change_gro_flush_timeout(struct net_device *dev, unsigned long val)

{

	dev->gro_flush_timeout = val;

	WRITE_ONCE(dev->gro_flush_timeout, val);

	return 0;

}
@@ -384,7 +384,7 @@ NETDEVICE_SHOW_RW(gro_flush_timeout, fmt_ulong); 


static int change_napi_defer_hard_irqs(struct net_device *dev, unsigned long val)

{

	dev->napi_defer_hard_irqs = val;

	WRITE_ONCE(dev->napi_defer_hard_irqs, val);

	return 0;

}

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