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@microsoft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 2 insertions, 16 deletions

diff --git a/fs/dax.c b/fs/dax.c
index e8f61ea690f7..31e9f51ac917 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1009,7 +1009,6 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
         unsigned long vaddr = vmf->address;
         int ret = VM_FAULT_NOPAGE;
         struct page *zero_page;
-        void *entry2;
         pfn_t pfn;
 
         zero_page = ZERO_PAGE(0);
@@ -1019,13 +1018,8 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
         }
 
         pfn = page_to_pfn_t(zero_page);
-        entry2 = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
-                        RADIX_DAX_ZERO_PAGE, false);
-        if (IS_ERR(entry2)) {
-                ret = VM_FAULT_SIGBUS;
-                goto out;
-        }
-
+        dax_insert_mapping_entry(mapping, vmf, entry, pfn, RADIX_DAX_ZERO_PAGE,
+                        false);
         vm_insert_mixed(vmf->vma, vaddr, pfn);
 out:
         trace_dax_load_hole(inode, vmf, ret);
@@ -1337,10 +1331,6 @@ static int 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,
@@ -1424,8 +1414,6 @@ static int 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,
                         RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false);
-        if (IS_ERR(ret))
-                goto fallback;
 
         ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
         if (!pmd_none(*(vmf->pmd))) {
@@ -1547,8 +1535,6 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 
                 entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
                                                 RADIX_DAX_PMD, write && !sync);
-                if (IS_ERR(entry))
-                        goto finish_iomap;
 
                 /*
                  * If we are doing synchronous page fault and inode needs fsync,