Re: [PATCH 05/05] svcrdma: Add dma map count and WARN_ON

[Tom Tucker <tom@opengridcomputing.com>]

On Mon, 2008-05-19 at 15:18 -0400, J. Bruce Fields wrote:
> On Sun, May 18, 2008 at 07:13:21PM -0500, Tom Tucker wrote:
> > Add a dma map count in order to verify that all DMA mapping resources
> > have been freed at unmount.
> 
> I'm not sure what you mean by "at unmount".

It would be clearer to say "when the transport is closed". I was testing
using unmount to cause the close and had unmount on-the-brain.

> 
> --b.
> 
> > 
> > Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
> > 
> > ---
> >  include/linux/sunrpc/svc_rdma.h          |    1 +
> >  net/sunrpc/xprtrdma/svc_rdma_recvfrom.c  |    1 +
> >  net/sunrpc/xprtrdma/svc_rdma_sendto.c    |    3 +++
> >  net/sunrpc/xprtrdma/svc_rdma_transport.c |    5 +++++
> >  4 files changed, 10 insertions(+), 0 deletions(-)
> > 
> > diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> > index 29bfc9b..0a9c431 100644
> > --- a/include/linux/sunrpc/svc_rdma.h
> > +++ b/include/linux/sunrpc/svc_rdma.h
> > @@ -105,6 +105,7 @@ struct svcxprt_rdma {
> >  
> >  	struct ib_pd         *sc_pd;
> >  
> > +	atomic_t	     sc_dma_used;
> >  	atomic_t	     sc_ctxt_used;
> >  	struct list_head     sc_ctxt_free;
> >  	int		     sc_ctxt_cnt;
> > diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> > index 174e888..9b3dff0 100644
> > --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> > +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> > @@ -229,6 +229,7 @@ static void rdma_set_ctxt_sge(struct svcxprt_rdma *xprt,
> >  	ctxt->count = count;
> >  	ctxt->direction = DMA_FROM_DEVICE;
> >  	for (i = 0; i < count; i++) {
> > +		atomic_inc(&xprt->sc_dma_used);
> >  		ctxt->sge[i].addr = (unsigned long)
> >  			ib_dma_map_single(xprt->sc_cm_id->device,
> >  					  (void*)sge[i].addr, sge[i].length,
> > diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> > index 85931c4..cdb0732 100644
> > --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> > +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> > @@ -174,6 +174,7 @@ static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
> >  		sge_bytes = min((size_t)bc,
> >  				(size_t)(xdr_sge[xdr_sge_no].length-sge_off));
> >  		sge[sge_no].length = sge_bytes;
> > +		atomic_inc(&xprt->sc_dma_used);
> >  		sge[sge_no].addr =
> >  			ib_dma_map_single(xprt->sc_cm_id->device,
> >  					  (void *)
> > @@ -399,6 +400,7 @@ static int send_reply(struct svcxprt_rdma *rdma,
> >  	ctxt->count = 1;
> >  
> >  	/* Prepare the SGE for the RPCRDMA Header */
> > +	atomic_inc(&rdma->sc_dma_used);
> >  	ctxt->sge[0].addr =
> >  		ib_dma_map_page(rdma->sc_cm_id->device,
> >  				page, 0, PAGE_SIZE, DMA_TO_DEVICE);
> > @@ -411,6 +413,7 @@ static int send_reply(struct svcxprt_rdma *rdma,
> >  		sge_bytes = min((size_t)ctxt->sge[sge_no].length,
> >  				(size_t)byte_count);
> >  		byte_count -= sge_bytes;
> > +		atomic_inc(&rdma->sc_dma_used);
> >  		ctxt->sge[sge_no].addr =
> >  			ib_dma_map_single(rdma->sc_cm_id->device,
> >  					  (void *)
> > diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> > index 8a50586..68908b5 100644
> > --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> > +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> > @@ -155,6 +155,7 @@ static void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
> >  	struct svcxprt_rdma *xprt = ctxt->xprt;
> >  	int i;
> >  	for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
> > +		atomic_dec(&xprt->sc_dma_used);
> >  		ib_dma_unmap_single(xprt->sc_cm_id->device,
> >  				    ctxt->sge[i].addr,
> >  				    ctxt->sge[i].length,
> > @@ -493,6 +494,7 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
> >  	cma_xprt->sc_max_requests = svcrdma_max_requests;
> >  	cma_xprt->sc_sq_depth = svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT;
> >  	atomic_set(&cma_xprt->sc_sq_count, 0);
> > +	atomic_set(&cma_xprt->sc_ctxt_used, 0);
> >  
> >  	if (!listener) {
> >  		int reqs = cma_xprt->sc_max_requests;
> > @@ -543,6 +545,7 @@ int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
> >  		BUG_ON(sge_no >= xprt->sc_max_sge);
> >  		page = svc_rdma_get_page();
> >  		ctxt->pages[sge_no] = page;
> > +		atomic_inc(&xprt->sc_dma_used);
> >  		pa = ib_dma_map_page(xprt->sc_cm_id->device,
> >  				     page, 0, PAGE_SIZE,
> >  				     DMA_FROM_DEVICE);
> > @@ -1023,6 +1026,7 @@ static void __svc_rdma_free(struct work_struct *work)
> >  
> >  	/* Warn if we leaked a resource or under-referenced */
> >  	WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
> > +	WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);
> >  
> >  	/* Destroy the QP if present (not a listener) */
> >  	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
> > @@ -1143,6 +1147,7 @@ void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
> >  	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
> >  
> >  	/* Prepare SGE for local address */
> > +	atomic_inc(&xprt->sc_dma_used);
> >  	sge.addr = ib_dma_map_page(xprt->sc_cm_id->device,
> >  				   p, 0, PAGE_SIZE, DMA_FROM_DEVICE);
> >  	sge.lkey = xprt->sc_phys_mr->lkey;