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Commit cd0a137a authored by Florian Fainelli's avatar Florian Fainelli Committed by David S. Miller
Browse files

net: core: Specify skb_pad()/skb_put_padto() SKB freeing 



Rename skb_pad() into __skb_pad() and make it take a third argument:
free_on_error which controls whether kfree_skb() should be called or
not, skb_pad() directly makes use of it and passes true to preserve its
existing behavior. Do exactly the same thing with __skb_put_padto() and
skb_put_padto().

Suggested-by: default avatarDavid Miller <davem@davemloft.net>
Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: default avatarWoojung Huh <Woojung.Huh@microchip.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 013dae5d

include/linux/skbuff.h

+37 −4
Original line number Diff line number Diff line
@@ -973,7 +973,23 @@ int __must_check skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg 
int __must_check skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg,

			      int offset, int len);

int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);

int skb_pad(struct sk_buff *skb, int pad);

int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error);



/**

 *	skb_pad			-	zero pad the tail of an skb

 *	@skb: buffer to pad

 *	@pad: space to pad

 *

 *	Ensure that a buffer is followed by a padding area that is zero

 *	filled. Used by network drivers which may DMA or transfer data

 *	beyond the buffer end onto the wire.

 *

 *	May return error in out of memory cases. The skb is freed on error.

 */

static inline int skb_pad(struct sk_buff *skb, int pad)

{

	return __skb_pad(skb, pad, true);

}

#define dev_kfree_skb(a)	consume_skb(a)



int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
@@ -2825,25 +2841,42 @@ static inline int skb_padto(struct sk_buff *skb, unsigned int len) 
 *	skb_put_padto - increase size and pad an skbuff up to a minimal size

 *	@skb: buffer to pad

 *	@len: minimal length

 *	@free_on_error: free buffer on error

 *

 *	Pads up a buffer to ensure the trailing bytes exist and are

 *	blanked. If the buffer already contains sufficient data it

 *	is untouched. Otherwise it is extended. Returns zero on

 *	success. The skb is freed on error.

 *	success. The skb is freed on error if @free_on_error is true.

 */

static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)

static inline int __skb_put_padto(struct sk_buff *skb, unsigned int len,

				  bool free_on_error)

{

	unsigned int size = skb->len;



	if (unlikely(size < len)) {

		len -= size;

		if (skb_pad(skb, len))

		if (__skb_pad(skb, len, free_on_error))

			return -ENOMEM;

		__skb_put(skb, len);

	}

	return 0;

}



/**

 *	skb_put_padto - increase size and pad an skbuff up to a minimal size

 *	@skb: buffer to pad

 *	@len: minimal length

 *

 *	Pads up a buffer to ensure the trailing bytes exist and are

 *	blanked. If the buffer already contains sufficient data it

 *	is untouched. Otherwise it is extended. Returns zero on

 *	success. The skb is freed on error.

 */

static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)

{

	return __skb_put_padto(skb, len, true);

}



static inline int skb_add_data(struct sk_buff *skb,

			       struct iov_iter *from, int copy)

{

net/core/skbuff.c

+8 −5
Original line number Diff line number Diff line
@@ -1363,18 +1363,20 @@ struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 
EXPORT_SYMBOL(skb_copy_expand);



/**

 *	skb_pad			-	zero pad the tail of an skb

 *	__skb_pad		-	zero pad the tail of an skb

 *	@skb: buffer to pad

 *	@pad: space to pad

 *	@free_on_error: free buffer on error

 *

 *	Ensure that a buffer is followed by a padding area that is zero

 *	filled. Used by network drivers which may DMA or transfer data

 *	beyond the buffer end onto the wire.

 *

 *	May return error in out of memory cases. The skb is freed on error.

 *	May return error in out of memory cases. The skb is freed on error

 *	if @free_on_error is true.

 */



int skb_pad(struct sk_buff *skb, int pad)

int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error)

{

	int err;

	int ntail;
@@ -1403,10 +1405,11 @@ int skb_pad(struct sk_buff *skb, int pad) 
	return 0;



free_skb:

	if (free_on_error)

		kfree_skb(skb);

	return err;

}

EXPORT_SYMBOL(skb_pad);

EXPORT_SYMBOL(__skb_pad);



/**

 *	pskb_put - add data to the tail of a potentially fragmented buffer