Another bugfix from the XArray work; please queue for merge. From: Matthew Wilcox <mawilcox(a)microsoft.com&gt; Date: Thu, 29 Mar 2018 22:47:50 -0400 Subject: [PATCH] dax: dax_insert_mapping_entry always succeeds It does not return an error, so we don't need to check the return value for IS_ERR(). Indeed, it is a bug to do so; with a sufficiently large PFN, a legitimate DAX entry may be mistaken for an error return. Signed-off-by: Matthew Wilcox <mawilcox(a)microsoft.com&gt; --- fs/dax.c | 18 ++---------------- 1 file changed, 2 insertions(+), 16 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index f643e8fc34ee..99c5084b845c 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1005,19 +1005,13 @@ static vm_fault_t dax_load_hole(struct address_space *mapping, void *entry, { struct inode *inode = mapping->host; unsigned long vaddr = vmf->address; - vm_fault_t ret = VM_FAULT_NOPAGE; - void *entry2; + vm_fault_t ret; pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr)); - entry2 = dax_insert_mapping_entry(mapping, vmf, entry, pfn, + dax_insert_mapping_entry(mapping, vmf, entry, pfn, DAX_ZERO_PAGE, false); - if (IS_ERR(entry2)) { - ret = VM_FAULT_SIGBUS; - goto out; - } ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); -out: trace_dax_load_hole(inode, vmf, ret); return ret; } @@ -1327,10 +1321,6 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn, 0, write && !sync); - if (IS_ERR(entry)) { - error = PTR_ERR(entry); - goto error_finish_iomap; - } /* * If we are doing synchronous page fault and inode needs fsync, @@ -1411,8 +1401,6 @@ static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, pfn = page_to_pfn_t(zero_page); ret = dax_insert_mapping_entry(mapping, vmf, entry, pfn, DAX_PMD | DAX_ZERO_PAGE, false); - if (IS_ERR(ret)) - goto fallback; ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); if (!pmd_none(*(vmf->pmd))) { @@ -1534,8 +1522,6 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn, DAX_PMD, write && !sync); - if (IS_ERR(entry)) - goto finish_iomap; /* * If we are doing synchronous page fault and inode needs fsync, -- 2.17.0