> On Sep 20, 2015, at 5:40 AM, Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx> wrote:
>
> On 9/17/2015 11:46 PM, Chuck Lever wrote:
>> To support backward direction calls, I'm going to add an
>> svc_rdma_get_context() call in the client RDMA transport.
>>
>> Called from ->buf_alloc(), we can't sleep waiting for memory.
>> So add an API that can get a server op_ctxt but won't sleep.
>>
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> ---
>> include/linux/sunrpc/svc_rdma.h | 2 ++
>> net/sunrpc/xprtrdma/svc_rdma_transport.c | 28 +++++++++++++++++++++++-----
>> 2 files changed, 25 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
>> index 6ce7495..2500dd1 100644
>> --- a/include/linux/sunrpc/svc_rdma.h
>> +++ b/include/linux/sunrpc/svc_rdma.h
>> @@ -224,6 +224,8 @@ extern void svc_rdma_send_error(struct svcxprt_rdma *, struct rpcrdma_msg *,
>> extern int svc_rdma_post_recv(struct svcxprt_rdma *);
>> extern int svc_rdma_create_listen(struct svc_serv *, int, struct sockaddr *);
>> extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
>> +extern struct svc_rdma_op_ctxt *svc_rdma_get_context_gfp(struct svcxprt_rdma *,
>> + gfp_t);
>> extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
>> extern void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt);
>> extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> index 23aba30..c4083a3 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> @@ -153,17 +153,35 @@ static void svc_rdma_bc_free(struct svc_xprt *xprt)
>> }
>> #endif /* CONFIG_SUNRPC_BACKCHANNEL */
>>
>> -struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
>> +static void svc_rdma_init_context(struct svcxprt_rdma *xprt,
>> + struct svc_rdma_op_ctxt *ctxt)
>> {
>> - struct svc_rdma_op_ctxt *ctxt;
>> -
>> - ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep,
>> - GFP_KERNEL | __GFP_NOFAIL);
>> ctxt->xprt = xprt;
>> INIT_LIST_HEAD(&ctxt->dto_q);
>> ctxt->count = 0;
>> ctxt->frmr = NULL;
>> atomic_inc(&xprt->sc_ctxt_used);
>> +}
>> +
>> +struct svc_rdma_op_ctxt *svc_rdma_get_context_gfp(struct svcxprt_rdma *xprt,
>> + gfp_t flags)
>> +{
>> + struct svc_rdma_op_ctxt *ctxt;
>> +
>> + ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep, flags);
>> + if (!ctxt)
>> + return NULL;
>> + svc_rdma_init_context(xprt, ctxt);
>> + return ctxt;
>> +}
>> +
>> +struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
>> +{
>
> Why not:
> return svc_rdma_get_context_gfp(xprt, GFP_KERNEL | __GFP_NOFAIL);
The “if (!ctxt) return NULL;” is unneeded if __GFP_NOFAIL is
specified.
I’ll wait for additional comments on this one, I could go
either way.
> ?
>
>> + struct svc_rdma_op_ctxt *ctxt;
>> +
>> + ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep,
>> + GFP_KERNEL | __GFP_NOFAIL);
>> + svc_rdma_init_context(xprt, ctxt);
>> return ctxt;
>> }
>>
>>
>> --
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>>
>
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—
Chuck Lever
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