diff mbox

[net-next] net: Cleanup skb cloning by adding SKB_FCLONE_FREE

Message ID 1412231620-3767-1-git-send-email-subramanian.vijay@gmail.com
State Superseded, archived
Delegated to: David Miller
Headers show

Commit Message

Vijay Subramanian Oct. 2, 2014, 6:33 a.m. UTC
SKB_FCLONE_UNAVAILABLE has overloaded meaning depending on type of skb.
1: If skb is allocated from head_cache, it indicates fclone is not available.
2: If skb is a companion fclone skb (allocated from fclone_cache), it indicates
it is available to be used.

To avoid confusion for case 2 above, this patch  replaces
SKB_FCLONE_UNAVAILABLE with SKB_FCLONE_FREE where appropriate. For fclone
companion skbs, this indicates it is free for use.

SKB_FCLONE_UNAVAILABLE will now simply indicate skb is from head_cache and
cannot / will not have a companion fclone.

Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
---
 include/linux/skbuff.h | 3 ++-
 net/core/skbuff.c      | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

Comments

Eric Dumazet Oct. 2, 2014, 11:35 a.m. UTC | #1
On Wed, 2014-10-01 at 23:33 -0700, Vijay Subramanian wrote:
> SKB_FCLONE_UNAVAILABLE has overloaded meaning depending on type of skb.
> 1: If skb is allocated from head_cache, it indicates fclone is not available.
> 2: If skb is a companion fclone skb (allocated from fclone_cache), it indicates
> it is available to be used.
> 
> To avoid confusion for case 2 above, this patch  replaces
> SKB_FCLONE_UNAVAILABLE with SKB_FCLONE_FREE where appropriate. For fclone
> companion skbs, this indicates it is free for use.
> 
> SKB_FCLONE_UNAVAILABLE will now simply indicate skb is from head_cache and
> cannot / will not have a companion fclone.
> 
> Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
> ---
>  include/linux/skbuff.h | 3 ++-
>  net/core/skbuff.c      | 8 ++++----
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 7c5036d..6c3fb9a 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -339,9 +339,10 @@ struct skb_shared_info {
>  
> 
>  enum {
> -	SKB_FCLONE_UNAVAILABLE,
> +	SKB_FCLONE_UNAVAILABLE,	/* skb has no fclone */
>  	SKB_FCLONE_ORIG,
>  	SKB_FCLONE_CLONE,
> +	SKB_FCLONE_FREE,	/* this fclone skb is available */
>  };
>  
Please comment all the states, now there is no ambiguity ?



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Vijay Subramanian Oct. 2, 2014, 4:36 p.m. UTC | #2
Sure. Will resend V2 shortly.

Vijay

On 2 October 2014 04:35, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Wed, 2014-10-01 at 23:33 -0700, Vijay Subramanian wrote:
>> SKB_FCLONE_UNAVAILABLE has overloaded meaning depending on type of skb.
>> 1: If skb is allocated from head_cache, it indicates fclone is not available.
>> 2: If skb is a companion fclone skb (allocated from fclone_cache), it indicates
>> it is available to be used.
>>
>> To avoid confusion for case 2 above, this patch  replaces
>> SKB_FCLONE_UNAVAILABLE with SKB_FCLONE_FREE where appropriate. For fclone
>> companion skbs, this indicates it is free for use.
>>
>> SKB_FCLONE_UNAVAILABLE will now simply indicate skb is from head_cache and
>> cannot / will not have a companion fclone.
>>
>> Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
>> ---
>>  include/linux/skbuff.h | 3 ++-
>>  net/core/skbuff.c      | 8 ++++----
>>  2 files changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
>> index 7c5036d..6c3fb9a 100644
>> --- a/include/linux/skbuff.h
>> +++ b/include/linux/skbuff.h
>> @@ -339,9 +339,10 @@ struct skb_shared_info {
>>
>>
>>  enum {
>> -     SKB_FCLONE_UNAVAILABLE,
>> +     SKB_FCLONE_UNAVAILABLE, /* skb has no fclone */
>>       SKB_FCLONE_ORIG,
>>       SKB_FCLONE_CLONE,
>> +     SKB_FCLONE_FREE,        /* this fclone skb is available */
>>  };
>>
> Please comment all the states, now there is no ambiguity ?
>
>
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7c5036d..6c3fb9a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -339,9 +339,10 @@  struct skb_shared_info {
 
 
 enum {
-	SKB_FCLONE_UNAVAILABLE,
+	SKB_FCLONE_UNAVAILABLE,	/* skb has no fclone */
 	SKB_FCLONE_ORIG,
 	SKB_FCLONE_CLONE,
+	SKB_FCLONE_FREE,	/* this fclone skb is available */
 };
 
 enum {
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index f77e648..6f4e359 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -265,7 +265,7 @@  struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 		skb->fclone = SKB_FCLONE_ORIG;
 		atomic_set(&fclones->fclone_ref, 1);
 
-		fclones->skb2.fclone = SKB_FCLONE_UNAVAILABLE;
+		fclones->skb2.fclone = SKB_FCLONE_FREE;
 		fclones->skb2.pfmemalloc = pfmemalloc;
 	}
 out:
@@ -542,7 +542,7 @@  static void kfree_skbmem(struct sk_buff *skb)
 		fclones = container_of(skb, struct sk_buff_fclones, skb2);
 
 		/* Warning : We must perform the atomic_dec_and_test() before
-		 * setting skb->fclone back to SKB_FCLONE_UNAVAILABLE, otherwise
+		 * setting skb->fclone back to SKB_FCLONE_FREE, otherwise
 		 * skb_clone() could set clone_ref to 2 before our decrement.
 		 * Anyway, if we are going to free the structure, no need to
 		 * rewrite skb->fclone.
@@ -553,7 +553,7 @@  static void kfree_skbmem(struct sk_buff *skb)
 			/* The clone portion is available for
 			 * fast-cloning again.
 			 */
-			skb->fclone = SKB_FCLONE_UNAVAILABLE;
+			skb->fclone = SKB_FCLONE_FREE;
 		}
 		break;
 	}
@@ -874,7 +874,7 @@  struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
 		return NULL;
 
 	if (skb->fclone == SKB_FCLONE_ORIG &&
-	    n->fclone == SKB_FCLONE_UNAVAILABLE) {
+	    n->fclone == SKB_FCLONE_FREE) {
 		n->fclone = SKB_FCLONE_CLONE;
 		/* As our fastclone was free, clone_ref must be 1 at this point.
 		 * We could use atomic_inc() here, but it is faster