[PATCH v2 02/24] xprtrdma: Remove FMRs from the unmap list after unmapping

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



ib_unmap_fmr() takes a list of FMRs to unmap. However, it does not
remove the FMRs from this list as it processes them. Other
ib_unmap_fmr() call sites are careful to remove FMRs from the list
after ib_unmap_fmr() returns.

Since commit 7c7a5390dc6c8 ("xprtrdma: Add ro_unmap_sync method for FMR")
fmr_op_unmap_sync passes more than one FMR to ib_unmap_fmr(), but
it didn't bother to remove the FMRs from that list once the call was
complete.

I've noticed some instability that could be related to list
tangling by the new fmr_op_unmap_sync() logic. In an abundance
of caution, add some defensive logic to clean up properly after
ib_unmap_fmr().

Fixes: 7c7a5390dc6c8 ("xprtrdma: Add ro_unmap_sync method for FMR")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
 net/sunrpc/xprtrdma/fmr_ops.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c
index 6326ebe..958c792 100644
--- a/net/sunrpc/xprtrdma/fmr_ops.c
+++ b/net/sunrpc/xprtrdma/fmr_ops.c
@@ -63,9 +63,12 @@ static int
 __fmr_unmap(struct rpcrdma_mw *mw)
 {
 	LIST_HEAD(l);
+	int rc;
 
 	list_add(&mw->fmr.fmr->list, &l);
-	return ib_unmap_fmr(&l);
+	rc = ib_unmap_fmr(&l);
+	list_del_init(&mw->fmr.fmr->list);
+	return rc;
 }
 
 /* Deferred reset of a single FMR. Generate a fresh rkey by
@@ -149,6 +152,7 @@ fmr_op_init(struct rpcrdma_xprt *r_xprt)
 		r->fmr.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr);
 		if (IS_ERR(r->fmr.fmr))
 			goto out_fmr_err;
+		INIT_LIST_HEAD(&r->fmr.fmr->list);
 
 		r->mw_xprt = r_xprt;
 		list_add(&r->mw_list, &buf->rb_mws);
@@ -267,7 +271,7 @@ fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 		seg = &req->rl_segments[i];
 		mw = seg->rl_mw;
 
-		list_add(&mw->fmr.fmr->list, &unmap_list);
+		list_add_tail(&mw->fmr.fmr->list, &unmap_list);
 
 		i += seg->mr_nsegs;
 	}
@@ -280,7 +284,9 @@ fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 	 */
 	for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) {
 		seg = &req->rl_segments[i];
+		mw = seg->rl_mw;
 
+		list_del_init(&mw->fmr.fmr->list);
 		__fmr_dma_unmap(r_xprt, seg);
 		rpcrdma_put_mw(r_xprt, seg->rl_mw);
 

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Filesystem Development]     [Linux USB Development]     [Linux Media Development]     [Video for Linux]     [Linux NILFS]     [Linux Audio Users]     [Yosemite Info]     [Linux SCSI]

  Powered by Linux