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Commit ed384464 authored by Milos Vyletel's avatar Milos Vyletel Committed by Paul E. McKenney
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documentation: State that rcu_dereference() reloads pointer 



Make a note stating that repeated calls of rcu_dereference() may not
return the same pointer if update happens while in critical section.

Reported-by: default avatarJeff Haran <jeff.haran@citrix.com>
Signed-off-by: default avatarMilos Vyletel <milos@redhat.com>
Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent ee7c29be

Documentation/RCU/whatisRCU.txt

+3 −1
Original line number Diff line number Diff line
@@ -256,7 +256,9 @@ rcu_dereference() 
	If you are going to be fetching multiple fields from the

	RCU-protected structure, using the local variable is of

	course preferred.  Repeated rcu_dereference() calls look

	ugly and incur unnecessary overhead on Alpha CPUs.

	ugly, do not guarantee that the same pointer will be returned

	if an update happened while in the critical section, and incur

	unnecessary overhead on Alpha CPUs.



	Note that the value returned by rcu_dereference() is valid

	only within the enclosing RCU read-side critical section.