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>

diff --git a/fs/dax.c b/fs/dax.c
index e8f61ea690f7e4be84f6a7167235e4cd2ba689dd..31e9f51ac917e22f5ee4bfdecdb83bc9527f686d 100644 (file)
--- 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,