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svcrdma: Poll CQs in "workqueue" mode 

svcrdma calls svc_xprt_put() in its completion handlers, which
currently run in IRQ context.

However, svc_xprt_put() is meant to be invoked in process context,
not in IRQ context. After the last transport reference is gone, it
directly calls a transport release function that expects to run in
process context.

Change the CQ polling modes to IB_POLL_WORKQUEUE so that svcrdma
invokes svc_xprt_put() only in process context. As an added benefit,
bottom half-disabled spin locking can be eliminated from I/O paths.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Chuck Lever 2017-02-07 11:59:04 -05:00 committed by J. Bruce Fields
parent a3ab867fa6
commit 81fa3275f9
2 changed files with 16 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
View File

@ -606,12 +606,12 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
dprintk("svcrdma: rqstp=%p\n", rqstp);
spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
spin_lock(&rdma_xprt->sc_rq_dto_lock);
if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
ctxt = list_first_entry(&rdma_xprt->sc_read_complete_q,
struct svc_rdma_op_ctxt, list);
list_del(&ctxt->list);
spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
rdma_read_complete(rqstp, ctxt);
goto complete;
} else if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
@ -623,7 +623,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
clear_bit(XPT_DATA, &xprt->xpt_flags);
ctxt = NULL;
}
spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
if (!ctxt) {
/* This is the EAGAIN path. The svc_recv routine will
* return -EAGAIN, the nfsd thread will go to call into

26
net/sunrpc/xprtrdma/svc_rdma_transport.c
View File

@ -188,7 +188,7 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
{
struct svc_rdma_op_ctxt *ctxt = NULL;
spin_lock_bh(&xprt->sc_ctxt_lock);
spin_lock(&xprt->sc_ctxt_lock);
xprt->sc_ctxt_used++;
if (list_empty(&xprt->sc_ctxts))
goto out_empty;
@ -196,7 +196,7 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
ctxt = list_first_entry(&xprt->sc_ctxts,
struct svc_rdma_op_ctxt, list);
list_del(&ctxt->list);
spin_unlock_bh(&xprt->sc_ctxt_lock);
spin_unlock(&xprt->sc_ctxt_lock);
out:
ctxt->count = 0;
@ -208,15 +208,15 @@ out_empty:
/* Either pre-allocation missed the mark, or send
* queue accounting is broken.
*/
spin_unlock_bh(&xprt->sc_ctxt_lock);
spin_unlock(&xprt->sc_ctxt_lock);
ctxt = alloc_ctxt(xprt, GFP_NOIO);
if (ctxt)
goto out;
spin_lock_bh(&xprt->sc_ctxt_lock);
spin_lock(&xprt->sc_ctxt_lock);
xprt->sc_ctxt_used--;
spin_unlock_bh(&xprt->sc_ctxt_lock);
spin_unlock(&xprt->sc_ctxt_lock);
WARN_ONCE(1, "svcrdma: empty RDMA ctxt list?\n");
return NULL;
}
@ -253,10 +253,10 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
for (i = 0; i < ctxt->count; i++)
put_page(ctxt->pages[i]);
spin_lock_bh(&xprt->sc_ctxt_lock);
spin_lock(&xprt->sc_ctxt_lock);
xprt->sc_ctxt_used--;
list_add(&ctxt->list, &xprt->sc_ctxts);
spin_unlock_bh(&xprt->sc_ctxt_lock);
spin_unlock(&xprt->sc_ctxt_lock);
}
static void svc_rdma_destroy_ctxts(struct svcxprt_rdma *xprt)
@ -921,14 +921,14 @@ struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
{
struct svc_rdma_fastreg_mr *frmr = NULL;
spin_lock_bh(&rdma->sc_frmr_q_lock);
spin_lock(&rdma->sc_frmr_q_lock);
if (!list_empty(&rdma->sc_frmr_q)) {
frmr = list_entry(rdma->sc_frmr_q.next,
struct svc_rdma_fastreg_mr, frmr_list);
list_del_init(&frmr->frmr_list);
frmr->sg_nents = 0;
}
spin_unlock_bh(&rdma->sc_frmr_q_lock);
spin_unlock(&rdma->sc_frmr_q_lock);
if (frmr)
return frmr;
@ -941,10 +941,10 @@ void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
if (frmr) {
ib_dma_unmap_sg(rdma->sc_cm_id->device,
frmr->sg, frmr->sg_nents, frmr->direction);
spin_lock_bh(&rdma->sc_frmr_q_lock);
spin_lock(&rdma->sc_frmr_q_lock);
WARN_ON_ONCE(!list_empty(&frmr->frmr_list));
list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
spin_unlock_bh(&rdma->sc_frmr_q_lock);
spin_unlock(&rdma->sc_frmr_q_lock);
}
}
@ -1026,13 +1026,13 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
goto errout;
}
newxprt->sc_sq_cq = ib_alloc_cq(dev, newxprt, newxprt->sc_sq_depth,
0, IB_POLL_SOFTIRQ);
0, IB_POLL_WORKQUEUE);
if (IS_ERR(newxprt->sc_sq_cq)) {
dprintk("svcrdma: error creating SQ CQ for connect request\n");
goto errout;
}
newxprt->sc_rq_cq = ib_alloc_cq(dev, newxprt, newxprt->sc_rq_depth,
0, IB_POLL_SOFTIRQ);
0, IB_POLL_WORKQUEUE);
if (IS_ERR(newxprt->sc_rq_cq)) {
dprintk("svcrdma: error creating RQ CQ for connect request\n");
goto errout;