Re: [PATCH] kernel: create linux/unaligned.h

[Randy Dunlap <randy.dunlap@oracle.com>]

On Thu, 20 Mar 2008 13:16:57 -0700 Harvey Harrison wrote:

> Add helpers for the following two patterns currently found in the
> kernel:
> 
> le32_to_cpu(get_unaligned((__le32 *)p));
> put_unaligned(cpu_to_le32(x), (__le32 *)p);
> 
> Becomes:
> le32_to_cpu_unaligned(p);
> cpu_to_le32_unaligned(x, p);
> 
> There are also some hand-rolled functions implementing this
> with byte-shifts that can be replaced.  To avoid new indirect
> includes of asm/unaligned.h, create linux/unaligned.h to make
> it opt in for new code that wants to use these helpers.
> 
> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
> ---
> This is a rollup of all the previous ones, added kerneldocs and
> have CC'd Randy.
> 
>  include/linux/unaligned.h |  138 +++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 138 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/unaligned.h b/include/linux/unaligned.h
> new file mode 100644
> index 0000000..035c1c7
> --- /dev/null
> +++ b/include/linux/unaligned.h
> @@ -0,0 +1,138 @@
> +#ifndef _LINUX_UNALIGNED_H_
> +#define _LINUX_UNALIGNED_H_
> +
> +#include <linux/types.h>
> +#include <asm/byteorder.h>
> +#include <asm/unaligned.h>
> +
> +#ifdef __KERNEL__
> +
> +/**
> + * le64_to_cpu_unaligned - read a le64 from a possibly unaligned pointer

I would write these as "an le64" etc., but then I read them as
"l e 64".


> + * @p: pointer to read from
> + *
> + * Returns a u64 in cpu byteorder

And I would write "CPU", but some people don't do that.  ;)

Acked-by: Randy Dunlap <randy.dunlap@oracle.com>


Thanks.

> + */
> +static inline u64 le64_to_cpu_unaligned(void *p)
> +{
> +	return le64_to_cpu(get_unaligned((__le64 *)p));
> +}
> +
> +/**
> + * le32_to_cpu_unaligned - read a le32 from a possibly unaligned pointer
> + * @p: pointer to read from
> + *
> + * Returns a u32 in cpu byteorder
> + */
> +static inline u32 le32_to_cpu_unaligned(void *p)
> +{
> +	return le32_to_cpu(get_unaligned((__le32 *)p));
> +}
> +
> +/**
> + * le16_to_cpu_unaligned - read a le16 from a possibly unaligned pointer
> + * @p: pointer to read from
> + *
> + * Returns a u16 in cpu byteorder
> + */
> +static inline u16 le16_to_cpu_unaligned(void *p)
> +{
> +	return le16_to_cpu(get_unaligned((__le16 *)p));
> +}
> +
> +/**
> + * be64_to_cpu_unaligned - read a be64 from a possibly unaligned pointer
> + * @p: pointer to read from
> + *
> + * Returns a u64 in cpu byteorder
> + */
> +static inline u64 be64_to_cpu_unaligned(void *p)
> +{
> +	return be64_to_cpu(get_unaligned((__be64 *)p));
> +}
> +
> +/**
> + * be32_to_cpu_unaligned - read a be32 from a possibly unaligned pointer
> + * @p: pointer to read from
> + *
> + * Returns a u32 in cpu byteorder
> + */
> +static inline u32 be32_to_cpu_unaligned(void *p)
> +{
> +	return be32_to_cpu(get_unaligned((__be32 *)p));
> +}
> +
> +/**
> + * be16_to_cpu_unaligned - read a be16 from a possibly unaligned pointer
> + * @p: pointer to read from
> + *
> + * Returns a u16 in cpu byteorder
> + */
> +static inline u16 be16_to_cpu_unaligned(void *p)
> +{
> +	return be16_to_cpu(get_unaligned((__be16 *)p));
> +}
> +
> +/**
> + * le64_to_cpu_unaligned - write a u64 in le-byteorder to a possibly unaligned pointer
> + * @val: value to be written
> + * @p: pointer to write to
> + */
> +static inline void cpu_to_le64_unaligned(u64 val, void *p)
> +{
> +	put_unaligned(cpu_to_le64(val), (__le64 *)p);
> +}
> +
> +/**
> + * le32_to_cpu_unaligned - write a u32 in le-byteorder to a possibly unaligned pointer
> + * @val: value to be written
> + * @p: pointer to write to
> + */
> +static inline void cpu_to_le32_unaligned(u32 val, void *p)
> +{
> +	put_unaligned(cpu_to_le32(val), (__le32 *)p);
> +}
> +
> +/**
> + * le16_to_cpu_unaligned - write a u16 in le-byteorder to a possibly unaligned pointer
> + * @val: value to be written
> + * @p: pointer to write to
> + */
> +static inline void cpu_to_le16_unaligned(u16 val, void *p)
> +{
> +	put_unaligned(cpu_to_le16(val), (__le16 *)p);
> +}
> +
> +/**
> + * be64_to_cpu_unaligned - write a u64 in be-byteorder to a possibly unaligned pointer
> + * @val: value to be written
> + * @p: pointer to write to
> + */
> +static inline void cpu_to_be64_unaligned(u64 val, void *p)
> +{
> +	put_unaligned(cpu_to_be64(val), (__be64 *)p);
> +}
> +
> +/**
> + * be32_to_cpu_unaligned - write a u32 in be-byteorder to a possibly unaligned pointer
> + * @val: value to be written
> + * @p: pointer to write to
> + */
> +static inline void cpu_to_be32_unaligned(u32 val, void *p)
> +{
> +	put_unaligned(cpu_to_be32(val), (__be32 *)p);
> +}
> +
> +/**
> + * be16_to_cpu_unaligned - write a u16 in be-byteorder to a possibly unaligned pointer
> + * @val: value to be written
> + * @p: pointer to write to
> + */
> +static inline void cpu_to_be16_unaligned(u16 val, void *p)
> +{
> +	put_unaligned(cpu_to_be16(val), (__be16 *)p);
> +}
> +
> +#endif /* KERNEL */
> +
> +#endif /* _LINUX_UNALIGNED_H */
> -- 

---
~Randy