Re: [PATCH v2 3/6] xprtrdma: Refactor invocations of offset_in_page()

[Chuck Lever <chuck.lever@oracle.com>]

> On Feb 3, 2021, at 1:09 PM, Tom Talpey <tom@talpey.com> wrote:
> 
> This looks good, but the earlier 1/6 patch depends on the offset_in_page
> conversion in rpcrdma_convert_kvec.

I don't think it does... sg_set_buf() handles the offset_in_page() calculation
in that case.


> Won't that complicate any bisection?
> 
> Reviewed-By: Tom Talpey <tom@talpey.com>
> 
> On 2/3/2021 11:24 AM, Chuck Lever wrote:
>> Clean up so that offset_in_page() is invoked less often in the
>> most common case, which is mapping xdr->pages.
>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>> ---
>>  net/sunrpc/xprtrdma/frwr_ops.c  |    8 +++-----
>>  net/sunrpc/xprtrdma/rpc_rdma.c  |    4 ++--
>>  net/sunrpc/xprtrdma/xprt_rdma.h |    2 +-
>>  3 files changed, 6 insertions(+), 8 deletions(-)
>> diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
>> index 13a50f77dddb..766a1048a48a 100644
>> --- a/net/sunrpc/xprtrdma/frwr_ops.c
>> +++ b/net/sunrpc/xprtrdma/frwr_ops.c
>> @@ -306,16 +306,14 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
>>  	if (nsegs > ep->re_max_fr_depth)
>>  		nsegs = ep->re_max_fr_depth;
>>  	for (i = 0; i < nsegs;) {
>> -		sg_set_page(&mr->mr_sg[i],
>> -			    seg->mr_page,
>> -			    seg->mr_len,
>> -			    offset_in_page(seg->mr_offset));
>> +		sg_set_page(&mr->mr_sg[i], seg->mr_page,
>> +			    seg->mr_len, seg->mr_offset);
>>    		++seg;
>>  		++i;
>>  		if (ep->re_mrtype == IB_MR_TYPE_SG_GAPS)
>>  			continue;
>> -		if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
>> +		if ((i < nsegs && seg->mr_offset) ||
>>  		    offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
>>  			break;
>>  	}
>> diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
>> index 529adb6ad4db..b3e66b8f65ab 100644
>> --- a/net/sunrpc/xprtrdma/rpc_rdma.c
>> +++ b/net/sunrpc/xprtrdma/rpc_rdma.c
>> @@ -215,7 +215,7 @@ rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
>>  {
>>  	if (vec->iov_len) {
>>  		seg->mr_page = virt_to_page(vec->iov_base);
>> -		seg->mr_offset = vec->iov_base;
>> +		seg->mr_offset = offset_in_page(vec->iov_base);
>>  		seg->mr_len = vec->iov_len;
>>  		++seg;
>>  		++(*n);
>> @@ -248,7 +248,7 @@ rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
>>  	page_base = offset_in_page(xdrbuf->page_base);
>>  	while (len) {
>>  		seg->mr_page = *ppages;
>> -		seg->mr_offset = (char *)page_base;
>> +		seg->mr_offset = page_base;
>>  		seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len);
>>  		len -= seg->mr_len;
>>  		++ppages;
>> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
>> index 02971e183989..ed1c5444fb9d 100644
>> --- a/net/sunrpc/xprtrdma/xprt_rdma.h
>> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h
>> @@ -287,7 +287,7 @@ enum {
>>  struct rpcrdma_mr_seg {
>>  	u32		mr_len;		/* length of segment */
>>  	struct page	*mr_page;	/* underlying struct page */
>> -	char		*mr_offset;	/* IN: page offset, OUT: iova */
>> +	u64		mr_offset;	/* IN: page offset, OUT: iova */
>>  };
>>    /* The Send SGE array is provisioned to send a maximum size

--
Chuck Lever