Re: [V9fs-developer] [RFC] [PATCH 2/7] [net/9p] Adds supporting functions for zero copy.

[Latchesar Ionkov <lucho@ionkov.net>]

Can you please rename the common structures so they don't have virtio
related names?

Thanks,
    Lucho

On Sun, Feb 6, 2011 at 11:56 PM, Venkateswararao Jujjuri (JV)
<jvrao@linux.vnet.ibm.com> wrote:
> On 2/6/2011 11:21 PM, Venkateswararao Jujjuri (JV) wrote:
>> Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
>> ---
>>  net/9p/Makefile       |    1 +
>>  net/9p/trans_common.c |   88 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  net/9p/trans_common.h |   26 ++++++++++++++
>>  3 files changed, 115 insertions(+), 0 deletions(-)
>>  create mode 100644 net/9p/trans_common.c
>>  create mode 100644 net/9p/trans_common.h
>>
>> diff --git a/net/9p/Makefile b/net/9p/Makefile
>> index 198a640..a0874cc 100644
>> --- a/net/9p/Makefile
>> +++ b/net/9p/Makefile
>> @@ -9,6 +9,7 @@ obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
>>       util.o \
>>       protocol.o \
>>       trans_fd.o \
>> +     trans_common.o \
>>
>>  9pnet_virtio-objs := \
>>       trans_virtio.o \
>> diff --git a/net/9p/trans_common.c b/net/9p/trans_common.c
>> new file mode 100644
>> index 0000000..dad57d2
>> --- /dev/null
>> +++ b/net/9p/trans_common.c
>> @@ -0,0 +1,88 @@
>> +/*
>> + * Copyright IBM Corporation, 2010
>> + * Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms of version 2.1 of the GNU Lesser General Public License
>> + * as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it would be useful, but
>> + * WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>> + *
>> + */
>> +
>> +#include <linux/slab.h>
>> +#include <net/9p/9p.h>
>> +#include <net/9p/client.h>
>> +#include <linux/scatterlist.h>
>> +#include "trans_common.h"
>> +
>> +/**
>> + *  p9_release_req_pages - Release pages after the transaction.
>> + *  @*private: PDU's private page of type virtio_rpage_info_t
>> + */
>> +void
>> +p9_release_req_pages(void *private)
>> +{
>> +     virtio_rpage_info_t *vpinfo = private;
>> +     int i = 0;
>> +
>> +     while (vpinfo->vp_data[i] && vpinfo->vp_nr_pages--) {
>> +             put_page(vpinfo->vp_data[i]);
>> +             i++;
>> +     }
>> +}
>> +
>> +/**
>> + * payload_gup - Calculates number of pages that needs to be pinned and
>> + * pins them ehter for read/write through get_user_pages_fast().
>> + */
>> +int
>> +payload_gup(struct p9_req_t *req, size_t *pdata_off, int *pdata_len, u8 rw)
>> +{
>> +     int nr_pages;
>> +     uint32_t first_page_bytes = 0;
>> +     uint32_t pdata_mapped_pages;
>> +     virtio_rpage_info_t  *rpinfo;
>> +
>> +     nr_pages = req->tc->pbuf_size >> PAGE_SHIFT;
>> +     *pdata_off = (size_t)req->tc->pbuf & (PAGE_SIZE-1);
>> +
>> +     if (*pdata_off)
>> +             first_page_bytes = min((PAGE_SIZE - *pdata_off),
>> +                             req->tc->pbuf_size);
>> +
>> +     if (req->tc->pbuf_size - (first_page_bytes + (nr_pages << PAGE_SHIFT))){
>> +             /* trailing partial page */
>> +             nr_pages++;
>> +     }
>> +     if (first_page_bytes) {
>> +             /* leading partial page */
>> +             nr_pages++;
>> +     }
>> +     /* TODO: Use buffer on PDU instead of allocating */
>> +     rpinfo = kmalloc(sizeof(virtio_rpage_info_t) +
>> +                     sizeof(struct page *) * nr_pages, GFP_KERNEL);
>> +     req->tc->private = (void *)rpinfo;
>> +     pdata_mapped_pages = get_user_pages_fast((unsigned long)req->tc->pbuf,
>> +                     nr_pages, rw, &rpinfo->vp_data[0]);
>> +
>> +     if (pdata_mapped_pages < 0) {
>> +             printk("get_user_pages_fast failed:%d udata:%p" "nr_pages:%d\n",
>> +                             pdata_mapped_pages, req->tc->pbuf, nr_pages);
>> +             pdata_mapped_pages = 0;
>> +             kfree(rpinfo);
>> +             return -EIO;
>> +     }
>> +     rpinfo->vp_nr_pages = pdata_mapped_pages;
>> +     if (*pdata_off) {
>> +             *pdata_len = first_page_bytes;
>> +             *pdata_len += min((req->tc->pbuf_size - *pdata_len),
>> +                             ((size_t)pdata_mapped_pages - 1) << PAGE_SHIFT);
>> +     } else {
>> +             *pdata_len = min (req->tc->pbuf_size,
>> +                             (size_t)pdata_mapped_pages << PAGE_SHIFT);
>> +     }
>> +     return 0;
>> +}
>> diff --git a/net/9p/trans_common.h b/net/9p/trans_common.h
>> new file mode 100644
>> index 0000000..8c85392
>> --- /dev/null
>> +++ b/net/9p/trans_common.h
>> @@ -0,0 +1,26 @@
>> +/*
>> + * Copyright IBM Corporation, 2010
>> + * Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms of version 2.1 of the GNU Lesser General Public License
>> + * as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it would be useful, but
>> + * WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>> + *
>> + */
>> +
>> +/**
>> + * struct virtio_rpage_info - To store mapped page information in PDU.
>> + * @vp_nr_pages: Number of mapped pages
>> + * @vp_data: Array of page pointers
>> + */
>> +typedef struct virtio_rpage_info {
>> +       int vp_nr_pages;
>> +       struct page *vp_data[0];
>> +} virtio_rpage_info_t;
>> +
>> +void p9_release_req_pages(void *);
>> +int payload_gup(struct p9_req_t *, size_t *, int *, u8);
>
>
>
> ------------------------------------------------------------------------------
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