Re: [Qemu-devel] [PATCH -v2 02/22] vrtio-9p: Implement P9_TVERSION for 9P

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 03/29/2010 02:01 AM, Aneesh Kumar K. V wrote:
> On Fri, 26 Mar 2010 11:15:47 -0500, Anthony Liguori<aliguori@linux.vnet.ibm.com>  wrote:
>    
>> On 03/16/2010 04:15 AM, Aneesh Kumar K.V wrote:
>>      
>>> From: Anthony Liguori<aliguori@us.ibm.com>
>>>
>>> [kiran@linux.vnet.ibm.com: malloc to qemu_malloc coversion]
>>>
>>> Signed-off-by: Anthony Liguori<aliguori@us.ibm.com>
>>> Signed-off-by: Aneesh Kumar K.V<aneesh.kumar@linux.vnet.ibm.com>
>>> ---
>>>    hw/virtio-9p.c |  263 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>>    1 files changed, 261 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
>>> index 115c93b..53b3d78 100644
>>> --- a/hw/virtio-9p.c
>>> +++ b/hw/virtio-9p.c
>>> @@ -111,10 +111,269 @@ static void free_pdu(V9fsState *s, V9fsPDU *pdu)
>>>        }
>>>    }
>>>
>>> +static void v9fs_string_free(V9fsString *str)
>>> +{
>>> +    free(str->data);
>>>
>>>        
>> qemu_free.
>>      
>>> +    str->data = NULL;
>>> +    str->size = 0;
>>> +}
>>> +
>>> +static size_t pdu_unpack(void *dst, V9fsPDU *pdu, size_t offset, size_t size)
>>> +{
>>> +    struct iovec *sg = pdu->elem.out_sg;
>>> +    BUG_ON((offset + size)>   sg[0].iov_len);
>>> +    memcpy(dst, sg[0].iov_base + offset, size);
>>> +    return size;
>>> +}
>>> +
>>> +/* FIXME i can do this with less variables */
>>> +static size_t pdu_pack(V9fsPDU *pdu, size_t offset, const void *src, size_t size)
>>> +{
>>> +    struct iovec *sg = pdu->elem.in_sg;
>>> +    size_t off = 0;
>>> +    size_t copied = 0;
>>> +    int i = 0;
>>> +
>>> +    for (i = 0; size&&   i<   pdu->elem.in_num; i++) {
>>> +        size_t len;
>>> +
>>> +        if (offset>= off&&   offset<   (off + sg[i].iov_len)) {
>>> +            len = MIN(sg[i].iov_len - (offset - off), size);
>>> +            memcpy(sg[i].iov_base + (offset - off), src, len);
>>> +            size -= len;
>>> +            offset += len;
>>> +            off = offset;
>>> +            copied += len;
>>> +            src += len;
>>> +        } else {
>>> +            off += sg[i].iov_len;
>>> +        }
>>> +    }
>>> +
>>> +    return copied;
>>> +}
>>> +
>>> +static int pdu_copy_sg(V9fsPDU *pdu, size_t offset, int rx, struct iovec *sg)
>>> +{
>>> +    size_t pos = 0;
>>> +    int i, j;
>>> +    struct iovec *src_sg;
>>> +    unsigned int num;
>>> +
>>> +    if (rx) {
>>> +        src_sg = pdu->elem.in_sg;
>>> +        num = pdu->elem.in_num;
>>> +    } else {
>>> +        src_sg = pdu->elem.out_sg;
>>> +        num = pdu->elem.out_num;
>>> +    }
>>> +
>>> +    j = 0;
>>> +    for (i = 0; i<   num; i++) {
>>> +        if (offset<= pos) {
>>> +            sg[j].iov_base = src_sg[i].iov_base;
>>> +            sg[j].iov_len = src_sg[i].iov_len;
>>> +            j++;
>>> +        } else if (offset<   (src_sg[i].iov_len + pos)) {
>>> +            sg[j].iov_base = src_sg[i].iov_base;
>>> +            sg[j].iov_len = src_sg[i].iov_len;
>>> +            sg[j].iov_base += (offset - pos);
>>> +            sg[j].iov_len -= (offset - pos);
>>> +            j++;
>>> +        }
>>> +        pos += src_sg[i].iov_len;
>>> +    }
>>> +
>>> +    return j;
>>> +}
>>> +
>>> +static size_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>>> +{
>>> +    size_t old_offset = offset;
>>> +    va_list ap;
>>> +    int i;
>>> +
>>> +    va_start(ap, fmt);
>>> +    for (i = 0; fmt[i]; i++) {
>>> +	switch (fmt[i]) {
>>> +	case 'b': {
>>> +	    int8_t *valp = va_arg(ap, int8_t *);
>>> +	    offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
>>> +	    break;
>>> +	}
>>> +	case 'w': {
>>> +	    int16_t *valp = va_arg(ap, int16_t *);
>>> +	    offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
>>> +	    break;
>>> +	}
>>> +	case 'd': {
>>> +	    int32_t *valp = va_arg(ap, int32_t *);
>>> +	    offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
>>> +	    break;
>>> +	}
>>> +	case 'q': {
>>> +	    int64_t *valp = va_arg(ap, int64_t *);
>>> +	    offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
>>> +	    break;
>>> +	}
>>> +	case 'v': {
>>> +	    struct iovec *iov = va_arg(ap, struct iovec *);
>>> +	    int *iovcnt = va_arg(ap, int *);
>>> +	    *iovcnt = pdu_copy_sg(pdu, offset, 0, iov);
>>> +	    break;
>>> +	}
>>> +	case 's': {
>>> +	    V9fsString *str = va_arg(ap, V9fsString *);
>>> +	    offset += pdu_unmarshal(pdu, offset, "w",&str->size);
>>> +	    /* FIXME: sanity check str->size */
>>> +	    str->data = qemu_malloc(str->size + 1);
>>> +	    offset += pdu_unpack(str->data, pdu, offset, str->size);
>>> +	    str->data[str->size] = 0;
>>> +	    break;
>>> +	}
>>> +	case 'Q': {
>>> +	    V9fsQID *qidp = va_arg(ap, V9fsQID *);
>>> +	    offset += pdu_unmarshal(pdu, offset, "bdq",
>>> +				&qidp->type,&qidp->version,&qidp->path);
>>> +	    break;
>>> +	}
>>> +	case 'S': {
>>> +	    V9fsStat *statp = va_arg(ap, V9fsStat *);
>>> +	    offset += pdu_unmarshal(pdu, offset, "wwdQdddqsssssddd",
>>> +				&statp->size,&statp->type,&statp->dev,
>>> +				&statp->qid,&statp->mode,&statp->atime,
>>> +				&statp->mtime,&statp->length,
>>> +				&statp->name,&statp->uid,&statp->gid,
>>> +				&statp->muid,&statp->extension,
>>> +				&statp->n_uid,&statp->n_gid,
>>> +				&statp->n_muid);
>>> +	    break;
>>> +	}
>>> +	default:
>>> +	    break;
>>> +	}
>>> +    }
>>> +
>>> +    va_end(ap);
>>> +
>>> +    return offset - old_offset;
>>> +}
>>> +
>>> +static size_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>>> +{
>>> +    size_t old_offset = offset;
>>> +    va_list ap;
>>> +    int i;
>>> +
>>> +    va_start(ap, fmt);
>>> +    for (i = 0; fmt[i]; i++) {
>>> +	switch (fmt[i]) {
>>> +	case 'b': {
>>> +	    int8_t val = va_arg(ap, int);
>>> +	    offset += pdu_pack(pdu, offset,&val, sizeof(val));
>>> +	    break;
>>> +	}
>>> +	case 'w': {
>>> +	    int16_t val = va_arg(ap, int);
>>> +	    offset += pdu_pack(pdu, offset,&val, sizeof(val));
>>> +	    break;
>>> +	}
>>> +	case 'd': {
>>> +	    int32_t val = va_arg(ap, int);
>>> +	    offset += pdu_pack(pdu, offset,&val, sizeof(val));
>>> +	    break;
>>> +	}
>>> +	case 'q': {
>>> +	    int64_t val = va_arg(ap, int64_t);
>>> +	    offset += pdu_pack(pdu, offset,&val, sizeof(val));
>>> +	    break;
>>> +	}
>>> +	case 'v': {
>>> +	    struct iovec *iov = va_arg(ap, struct iovec *);
>>> +	    int *iovcnt = va_arg(ap, int *);
>>> +	    *iovcnt = pdu_copy_sg(pdu, offset, 1, iov);
>>> +	    break;
>>> +	}
>>> +	case 's': {
>>> +	    V9fsString *str = va_arg(ap, V9fsString *);
>>> +	    offset += pdu_marshal(pdu, offset, "w", str->size);
>>> +	    offset += pdu_pack(pdu, offset, str->data, str->size);
>>> +	    break;
>>> +	}
>>> +	case 'Q': {
>>> +	    V9fsQID *qidp = va_arg(ap, V9fsQID *);
>>> +	    offset += pdu_marshal(pdu, offset, "bdq",
>>> +				  qidp->type, qidp->version, qidp->path);
>>> +	    break;
>>> +	}
>>> +	case 'S': {
>>> +	    V9fsStat *statp = va_arg(ap, V9fsStat *);
>>> +	    offset += pdu_marshal(pdu, offset, "wwdQdddqsssssddd",
>>> +				  statp->size, statp->type, statp->dev,
>>> +				&statp->qid, statp->mode, statp->atime,
>>> +				  statp->mtime, statp->length,&statp->name,
>>> +				&statp->uid,&statp->gid,&statp->muid,
>>> +				&statp->extension, statp->n_uid,
>>> +				  statp->n_gid, statp->n_muid);
>>> +	    break;
>>> +	}
>>> +	default:
>>> +	    break;
>>> +	}
>>> +    }
>>> +    va_end(ap);
>>> +
>>> +    return offset - old_offset;
>>> +}
>>>
>>>        
>> Adding the marshalling in  patch to implement P9_TVERSION is probably
>> not ideal.
>>
>>      
> Qemu Makefile rules won't allow to add functions that are not used. The
> error checking is strict. So there is not an easy way i can add these
> functional logically and let each of the changeset successfully build.
>    

Something like (void)pdu_marshal; should keep GCC happy.

Regards,

Anthony Liguori

> Any suggestions how to do the above ?
>
> -aneesh
>