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authorTrond Myklebust <trond.myklebust@primarydata.com>2016-03-16 16:24:36 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2016-03-16 16:25:09 -0400
commit1425075e7272faaa3629a1e2df679c0ba4cf55d3 (patch)
tree6d79a735f8a02d6dc9e27b915f6244fe1ab6b7ff /mm/memory.c
parent849dc3244c916545790bfb9055625a3719061c92 (diff)
parent2fa8f88d8892507ecff0126fbc67906740491d31 (diff)
Merge tag 'nfs-rdma-4.6-1' of git://git.linux-nfs.org/projects/anna/nfs-rdma
NFS: NFSoRDMA Client Side Changes These patches include several bugfixes and cleanups for the NFSoRDMA client. This includes bugfixes for NFS v4.1, proper RDMA_ERROR handling, and fixes from the recent workqueue swicchover. These patches also switch xprtrdma to use the new CQ API Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> * tag 'nfs-rdma-4.6-1' of git://git.linux-nfs.org/projects/anna/nfs-rdma: (787 commits) xprtrdma: Use new CQ API for RPC-over-RDMA client send CQs xprtrdma: Use an anonymous union in struct rpcrdma_mw xprtrdma: Use new CQ API for RPC-over-RDMA client receive CQs xprtrdma: Serialize credit accounting again xprtrdma: Properly handle RDMA_ERROR replies rpcrdma: Add RPCRDMA_HDRLEN_ERR xprtrdma: Do not wait if ib_post_send() fails xprtrdma: Segment head and tail XDR buffers on page boundaries xprtrdma: Clean up dprintk format string containing a newline xprtrdma: Clean up physical_op_map() xprtrdma: Clean up unused RPCRDMA_INLINE_PAD_THRESH macro
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 635451abc8f7..8132787ae4d5 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3404,8 +3404,18 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
if (unlikely(pmd_none(*pmd)) &&
unlikely(__pte_alloc(mm, vma, pmd, address)))
return VM_FAULT_OOM;
- /* if an huge pmd materialized from under us just retry later */
- if (unlikely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd)))
+ /*
+ * If a huge pmd materialized under us just retry later. Use
+ * pmd_trans_unstable() instead of pmd_trans_huge() to ensure the pmd
+ * didn't become pmd_trans_huge under us and then back to pmd_none, as
+ * a result of MADV_DONTNEED running immediately after a huge pmd fault
+ * in a different thread of this mm, in turn leading to a misleading
+ * pmd_trans_huge() retval. All we have to ensure is that it is a
+ * regular pmd that we can walk with pte_offset_map() and we can do that
+ * through an atomic read in C, which is what pmd_trans_unstable()
+ * provides.
+ */
+ if (unlikely(pmd_trans_unstable(pmd) || pmd_devmap(*pmd)))
return 0;
/*
* A regular pmd is established and it can't morph into a huge pmd