SUNRPC: Add a helper function xdr_inline_peek
We sometimes need to be able to read ahead in an xdr_stream without incrementing the current pointer position. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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@ -201,6 +201,7 @@ extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
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extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
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unsigned int base, unsigned int len);
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extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
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extern __be32 *xdr_inline_peek(struct xdr_stream *xdr, size_t nbytes);
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extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
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extern void xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
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extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
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@ -572,6 +572,27 @@ void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
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}
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EXPORT_SYMBOL_GPL(xdr_init_decode);
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/**
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* xdr_inline_peek - Allow read-ahead in the XDR data stream
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* @xdr: pointer to xdr_stream struct
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* @nbytes: number of bytes of data to decode
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*
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* Check if the input buffer is long enough to enable us to decode
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* 'nbytes' more bytes of data starting at the current position.
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* If so return the current pointer without updating the current
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* pointer position.
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*/
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__be32 * xdr_inline_peek(struct xdr_stream *xdr, size_t nbytes)
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{
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__be32 *p = xdr->p;
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__be32 *q = p + XDR_QUADLEN(nbytes);
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if (unlikely(q > xdr->end || q < p))
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return NULL;
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return p;
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}
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EXPORT_SYMBOL_GPL(xdr_inline_peek);
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/**
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* xdr_inline_decode - Retrieve non-page XDR data to decode
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* @xdr: pointer to xdr_stream struct
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