[openib-general] Re: [PATCH 01/13] [RFC] ipath basic headers

[Pekka Enberg]

Hi Roland,

On 12/17/05, Roland Dreier <rolandd at cisco.com> wrote:
> +/*
> + * This file contains defines, structures, etc. that are used
> + * to communicate between kernel and user code.
> + */
> +
> +#ifdef __KERNEL__
> +#include <linux/ioctl.h>
> +#include <linux/uio.h>
> +#include <asm/atomic.h>
> +#else                          /* !__KERNEL__; user mode */
> +#include <sys/ioctl.h>
> +#include <sys/uio.h>
> +#include <sys/types.h>
> +#include <stdint.h>
> +
> +/* these aren't implemented for user mode, which is OK until we multi-thread */
> +typedef struct _atomic {
> +       uint32_t counter;
> +} atomic_t;                    /* no atomic_t type in user-land */
> +#define atomic_set(a,v) ((a)->counter = (v))
> +#define atomic_inc_return(a)  (++(a)->counter)
> +#define likely(x) (x)
> +#define unlikely(x) (x)
> +
> +#define yield() sched_yield()
> +
> +/*
> + * too horrible to try and use the kernel get_cycles() or equivalent,
> + * so define and inline it here
> + */
> +
> +#if !defined(rdtscll)
> +#if defined(__x86_64) || defined(__i386)
> +#define rdtscll(v) do {uint32_t a,d;asm volatile("rdtsc" : "=a" (a), "=d" (d)); \
> +         (v) = ((uint64_t)a) | (((uint64_t)d)<<32); \
> +} while(0)
> +#else
> +#error "No cycle counter routine implemented yet for this platform"
> +#endif
> +#endif                         /* !defined(rdtscll) */

Do we really need this ugly userspace emulation code in the kernel?

> +/*
> + * this is used for very short copies, usually 1 - 8 bytes,
> + * *NEVER* to the PIO buffers!!!!!!!  use ipath_dwordcpy for longer
> + * copies, or any copy to the PIO buffers.  Works for 32 and 64 bit
> + * gcc and pathcc
> + */
> +static __inline__ void ipath_shortcopy(void *dest, void *src, uint32_t cnt)
> +{
> +       void *ssv, *dsv;
> +       uint32_t csv;
> +       __asm__ __volatile__("cld\n\trep\n\tmovsb":"=&c"(csv), "=&D"(dsv),
> +                            "=&S"(ssv)
> +                            :"0"(cnt), "1"(dest), "2"(src)
> +                            :"memory");
> +}
> +
> +/*
> + * optimized word copy; good for rev C and later opterons.  Among the best for
> + * short copies, and does as well or slightly better than the optimizization
> + * guide copies 6 and 8 at 2KB.
> + */
> +void ipath_dwordcpy(uint32_t * dest, uint32_t * src, uint32_t ndwords);

What is this used for? Why can't yo use memcpy?

> +#define round_up(v,sz) (((v) + (sz)-1) & ~((sz)-1))

Please use ALIGN().

> +/* These are used in the driver, don't use them elsewhere */
> +#define _IPATH_SIMFUNC_IOCTL_LOW 1
> +#define _IPATH_SIMFUNC_IOCTL_HIGH 7
> +
> +/*
> + * These tell the driver which ioctl's belong to the diags interface.
> + * As above, don't use them elsewhere.
> + */
> +#define _IPATH_DIAG_IOCTL_LOW 100
> +#define _IPATH_DIAG_IOCTL_HIGH 109

[snip, snip]

You seem to be introducing loads of new ioctls. Any reason you can't
use sysfs and/or configfs?

> +/* macros for processing rcvhdrq entries */
> +#define ips_get_hdr_err_flags(StartOfBuffer) *(((uint32_t *)(StartOfBuffer))+1)
> +#define ips_get_index(StartOfBuffer) (((*((uint32_t *)(StartOfBuffer))) >> \
> +        INFINIPATH_RHF_EGRINDEX_SHIFT) & INFINIPATH_RHF_EGRINDEX_MASK)
> +#define ips_get_rcv_type(StartOfBuffer)  ((*(((uint32_t *)(StartOfBuffer))) >> \
> +        INFINIPATH_RHF_RCVTYPE_SHIFT) & INFINIPATH_RHF_RCVTYPE_MASK)
> +#define ips_get_length_in_bytes(StartOfBuffer) \
> +        (uint32_t)(((*(((uint32_t *)(StartOfBuffer))) >> \
> +        INFINIPATH_RHF_LENGTH_SHIFT) & INFINIPATH_RHF_LENGTH_MASK) << 2)
> +#define ips_get_first_protocol_header(StartOfBuffer) (void *) \
> +        ((uint32_t *)(StartOfBuffer) + 2)
> +#define ips_get_ips_header(StartOfBuffer) ((ips_message_header_typ *) \
> +        ((uint32_t *)(StartOfBuffer) + 2))
> +#define ips_get_ipath_ver(ipath_header) (((ipath_header) >> INFINIPATH_I_VERS_SHIFT) \
> +        & INFINIPATH_I_VERS_MASK)

Please use static inlines instead for readability.