On Thu, Apr 19 2018, Herbert Xu wrote: > On Thu, Apr 19, 2018 at 08:56:28AM +1000, NeilBrown wrote: >> >> I don't want to do that - I just want the documentation to be correct >> (or at least, not be blatantly incorrect). The function does not sleep, >> and is safe to call with spin locks held. >> Do we need to spell out when it can be called? If so, maybe: >> >> This function may be called from any process context, including >> non-preemptable context, but cannot be called from interrupts. > > Just to make it perfectly clear, how about "cannot be called from > softirq or hardirq context"? Previously the not able to sleep part > completely ruled out any ambiguity but the new wording could confuse > people into thinking that this can be called from softirq context > where it would be unsafe if mixed with process context usage. >
Sound fair. Could you Ack the following? Then I'll resend all the
patches that have an ack.
I've realised that the "further improve stability of rhashtable_walk"
patch isn't actually complete, so I'll withdraw that for now.
Thanks,
NeilBrown
From e16c037398b6c057787437f3a0aaa7fd44c3bee3 Mon Sep 17 00:00:00 2001
From: NeilBrown <ne...@suse.com>
Date: Mon, 16 Apr 2018 11:05:39 +1000
Subject: [PATCH] rhashtable: Revise incorrect comment on
r{hl,hash}table_walk_enter()
Neither rhashtable_walk_enter() or rhltable_walk_enter() sleep, though
they do take a spinlock without irq protection.
So revise the comments to accurately state the contexts in which
these functions can be called.
Signed-off-by: NeilBrown <ne...@suse.com>
---
include/linux/rhashtable.h | 5 +++--
lib/rhashtable.c | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 87d443a5b11d..4e1f535c2034 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1268,8 +1268,9 @@ static inline int rhashtable_walk_init(struct rhashtable
*ht,
* For a completely stable walk you should construct your own data
* structure outside the hash table.
*
- * This function may sleep so you must not call it from interrupt
- * context or with spin locks held.
+ * This function may be called from any process context, including
+ * non-preemptable context, but cannot be called from softirq or
+ * hardirq context.
*
* You must call rhashtable_walk_exit after this function returns.
*/
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 2b2b79974b61..6d490f51174e 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -668,8 +668,9 @@ EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
* For a completely stable walk you should construct your own data
* structure outside the hash table.
*
- * This function may sleep so you must not call it from interrupt
- * context or with spin locks held.
+ * This function may be called from any process context, including
+ * non-preemptable context, but cannot be called from softirq or
+ * hardirq context.
*
* You must call rhashtable_walk_exit after this function returns.
*/
--
2.14.0.rc0.dirty
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