Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected() with rcu_replace_pointer()
On 12/12/19 2:46 AM, Paul E. McKenney wrote:
> On Wed, Dec 11, 2019 at 12:42:00PM +0800, Ying Xue wrote:
>> On 12/11/19 10:00 AM, Tuong Lien Tong wrote:
/* Move passive key if any */
if (key.passive) {
- tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, >lock);
+ tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2,
>>> >lock);
>>> The 3rd parameter should be the lockdep condition checking instead of the
>>> spinlock's pointer i.e. "lockdep_is_held(>lock)"?
>>> That's why I'd prefer to use the 'tipc_aead_rcu_swap ()' macro, which is
>>> clear & concise at least for the context here. It might be re-used later as
>>> well...
>>>
>>
>> Right. The 3rd parameter of rcu_replace_pointer() should be
>> "lockdep_is_held(>lock)" instead of ">lock".
>
> Like this?
Yes, I think it's better to set the 3rd parameter of
rcu_replace_pointer() with "lockdep_is_held(>lock)".
>
> Thanx, Paul
>
>
>
> commit 575bb4ba1b22383656760feb3d122e11656ccdfd
> Author: Paul E. McKenney
> Date: Mon Dec 9 19:13:45 2019 -0800
>
> net/tipc: Replace rcu_swap_protected() with rcu_replace_pointer()
>
> This commit replaces the use of rcu_swap_protected() with the more
> intuitively appealing rcu_replace_pointer() as a step towards removing
> rcu_swap_protected().
>
> Link:
> https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=z7-ggtm6wcvtyytxza1+bhqta4gg...@mail.gmail.com/
> Reported-by: Linus Torvalds
> Reported-by: kbuild test robot
> Signed-off-by: Paul E. McKenney
> [ paulmck: Updated based on Ying Xue and Tuong Lien Tong feedback. ]
> Cc: Jon Maloy
> Cc: Ying Xue
> Cc: "David S. Miller"
> Cc:
> Cc:
>
> diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
> index 990a872..c8c47fc 100644
> --- a/net/tipc/crypto.c
> +++ b/net/tipc/crypto.c
> @@ -257,9 +257,6 @@ static char *tipc_key_change_dump(struct tipc_key old,
> struct tipc_key new,
> #define tipc_aead_rcu_ptr(rcu_ptr, lock) \
> rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
>
> -#define tipc_aead_rcu_swap(rcu_ptr, ptr, lock)
> \
> - rcu_swap_protected((rcu_ptr), (ptr), lockdep_is_held(lock))
> -
> #define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)\
> do { \
> typeof(rcu_ptr) __tmp = rcu_dereference_protected((rcu_ptr),\
> @@ -1189,7 +1186,7 @@ static bool tipc_crypto_key_try_align(struct
> tipc_crypto *rx, u8 new_pending)
>
> /* Move passive key if any */
> if (key.passive) {
> - tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, >lock);
> + tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2,
> lockdep_is_held(>lock));
> x = (key.passive - key.pending + new_pending) % KEY_MAX;
> new_passive = (x <= 0) ? x + KEY_MAX : x;
> }
>
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Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected() with rcu_replace_pointer()
On 12/11/19 10:00 AM, Tuong Lien Tong wrote:
>>
>> /* Move passive key if any */
>> if (key.passive) {
>> -tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, >lock);
>> +tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2,
> >lock);
> The 3rd parameter should be the lockdep condition checking instead of the
> spinlock's pointer i.e. "lockdep_is_held(>lock)"?
> That's why I'd prefer to use the 'tipc_aead_rcu_swap ()' macro, which is
> clear & concise at least for the context here. It might be re-used later as
> well...
>
Right. The 3rd parameter of rcu_replace_pointer() should be
"lockdep_is_held(>lock)" instead of ">lock".
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Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected() with rcu_replace_pointer()
On 12/11/19 11:17 AM, Paul E. McKenney wrote: >> Acked-by: Ying Xue > As in the following? If so, I will be very happy to apply your Acked-by. Yes. Thanks! ___ tipc-discussion mailing list tipc-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tipc-discussion
Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected() with rcu_replace_pointer()
Hi Ying, Paul,
Please see my comments inline. Thanks!
BR/Tuong
-Original Message-
From: Ying Xue
Sent: Wednesday, December 11, 2019 8:32 AM
To: paul...@kernel.org
Cc: net...@vger.kernel.org; linux-ker...@vger.kernel.org; mi...@kernel.org;
tipc-discussion@lists.sourceforge.net; kernel-t...@fb.com;
torva...@linux-foundation.org; da...@davemloft.net
Subject: Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected()
with rcu_replace_pointer()
On 12/11/19 6:38 AM, Paul E. McKenney wrote:
> commit 4ee8e2c68b076867b7a5af82a38010fffcab611c
> Author: Paul E. McKenney
> Date: Mon Dec 9 19:13:45 2019 -0800
>
> net/tipc: Replace rcu_swap_protected() with rcu_replace_pointer()
>
> This commit replaces the use of rcu_swap_protected() with the more
> intuitively appealing rcu_replace_pointer() as a step towards removing
> rcu_swap_protected().
>
> Link:
https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4g
g...@mail.gmail.com/
> Reported-by: Linus Torvalds
> Reported-by: kbuild test robot
> Signed-off-by: Paul E. McKenney
> Cc: Jon Maloy
> Cc: Ying Xue
> Cc: "David S. Miller"
> Cc:
> Cc:
>
Acked-by: Ying Xue
> diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
> index 990a872..978d2db 100644
> --- a/net/tipc/crypto.c
> +++ b/net/tipc/crypto.c
> @@ -257,9 +257,6 @@ static char *tipc_key_change_dump(struct tipc_key old,
struct tipc_key new,
> #define tipc_aead_rcu_ptr(rcu_ptr, lock) \
> rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
>
> -#define tipc_aead_rcu_swap(rcu_ptr, ptr, lock)
\
> - rcu_swap_protected((rcu_ptr), (ptr), lockdep_is_held(lock))
> -
> #define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)\
> do { \
> typeof(rcu_ptr) __tmp = rcu_dereference_protected((rcu_ptr),\
> @@ -1189,7 +1186,7 @@ static bool tipc_crypto_key_try_align(struct
tipc_crypto *rx, u8 new_pending)
>
> /* Move passive key if any */
> if (key.passive) {
> - tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, >lock);
> + tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2,
>lock);
The 3rd parameter should be the lockdep condition checking instead of the
spinlock's pointer i.e. "lockdep_is_held(>lock)"?
That's why I'd prefer to use the 'tipc_aead_rcu_swap ()' macro, which is
clear & concise at least for the context here. It might be re-used later as
well...
> x = (key.passive - key.pending + new_pending) % KEY_MAX;
> new_passive = (x <= 0) ? x + KEY_MAX : x;
> }
>
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Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected() with rcu_replace_pointer()
On 12/11/19 6:38 AM, Paul E. McKenney wrote:
> commit 4ee8e2c68b076867b7a5af82a38010fffcab611c
> Author: Paul E. McKenney
> Date: Mon Dec 9 19:13:45 2019 -0800
>
> net/tipc: Replace rcu_swap_protected() with rcu_replace_pointer()
>
> This commit replaces the use of rcu_swap_protected() with the more
> intuitively appealing rcu_replace_pointer() as a step towards removing
> rcu_swap_protected().
>
> Link:
> https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=z7-ggtm6wcvtyytxza1+bhqta4gg...@mail.gmail.com/
> Reported-by: Linus Torvalds
> Reported-by: kbuild test robot
> Signed-off-by: Paul E. McKenney
> Cc: Jon Maloy
> Cc: Ying Xue
> Cc: "David S. Miller"
> Cc:
> Cc:
>
Acked-by: Ying Xue
> diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
> index 990a872..978d2db 100644
> --- a/net/tipc/crypto.c
> +++ b/net/tipc/crypto.c
> @@ -257,9 +257,6 @@ static char *tipc_key_change_dump(struct tipc_key old,
> struct tipc_key new,
> #define tipc_aead_rcu_ptr(rcu_ptr, lock) \
> rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
>
> -#define tipc_aead_rcu_swap(rcu_ptr, ptr, lock)
> \
> - rcu_swap_protected((rcu_ptr), (ptr), lockdep_is_held(lock))
> -
> #define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)\
> do { \
> typeof(rcu_ptr) __tmp = rcu_dereference_protected((rcu_ptr),\
> @@ -1189,7 +1186,7 @@ static bool tipc_crypto_key_try_align(struct
> tipc_crypto *rx, u8 new_pending)
>
> /* Move passive key if any */
> if (key.passive) {
> - tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, >lock);
> + tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2,
> >lock);
> x = (key.passive - key.pending + new_pending) % KEY_MAX;
> new_passive = (x <= 0) ? x + KEY_MAX : x;
> }
>
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Re: [tipc-discussion] [PATCH net/tipc] Replace rcu_swap_protected() with rcu_replace_pointer()
On 12/10/19 11:31 AM, Paul E. McKenney wrote:
> This commit replaces the use of rcu_swap_protected() with the more
> intuitively appealing rcu_replace_pointer() as a step towards removing
> rcu_swap_protected().
>
> Link:
> https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=z7-ggtm6wcvtyytxza1+bhqta4gg...@mail.gmail.com/
> Reported-by: Linus Torvalds
> Reported-by: kbuild test robot
> Signed-off-by: Paul E. McKenney
> Cc: Jon Maloy
> Cc: Ying Xue
> Cc: "David S. Miller"
> Cc:
> Cc:
>
> diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
> index 990a872..64cf831 100644
> --- a/net/tipc/crypto.c
> +++ b/net/tipc/crypto.c
> @@ -258,7 +258,7 @@ static char *tipc_key_change_dump(struct tipc_key old,
> struct tipc_key new,
> rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
>
> #define tipc_aead_rcu_swap(rcu_ptr, ptr, lock)
> \
> - rcu_swap_protected((rcu_ptr), (ptr), lockdep_is_held(lock))
> + rcu_replace_pointer((rcu_ptr), (ptr), lockdep_is_held(lock))
(ptr) = rcu_replace_pointer((rcu_ptr), (ptr), lockdep_is_held(lock))
>
> #define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)\
> do { \
> @@ -1189,7 +1189,7 @@ static bool tipc_crypto_key_try_align(struct
> tipc_crypto *rx, u8 new_pending)
>
> /* Move passive key if any */
> if (key.passive) {
> - tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, >lock);
> + tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2,
> >lock);
tipc_aead_rcu_swap() is only called here in TIPC module. If we use
rcu_replace_pointer() to switch pointers instead of calling
tipc_aead_rcu_swap() macro, I think we should completely remove
tipc_aead_rcu_swap().
> x = (key.passive - key.pending + new_pending) % KEY_MAX;
> new_passive = (x <= 0) ? x + KEY_MAX : x;
> }
>
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