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authorSouptick Joarder <jrdr.linux@gmail.com>2018-06-07 17:04:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 17:34:33 -0700
commitab77dab46210bb630e06c6803c5d84074bacd351 (patch)
tree1b0c7f6899d1438d11fa3fab5353318539aafd96 /mm/memory.c
parent3036bc45364f98515a2c446d7fac2c34dcfbeff4 (diff)
fs/dax.c: use new return type vm_fault_t
Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. commit 1c8f422059ae ("mm: change return type to vm_fault_t") There was an existing bug inside dax_load_hole() if vm_insert_mixed had failed to allocate a page table, we'd return VM_FAULT_NOPAGE instead of VM_FAULT_OOM. With new vmf_insert_mixed() this issue is addressed. vm_insert_mixed_mkwrite has inefficiency when it returns an error value, driver has to convert it to vm_fault_t type. With new vmf_insert_mixed_mkwrite() this limitation will be addressed. Link: http://lkml.kernel.org/r/20180510181121.GA15239@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 01f5464e0fd2..6a97893a8de7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1955,12 +1955,25 @@ int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
}
EXPORT_SYMBOL(vm_insert_mixed);
-int vm_insert_mixed_mkwrite(struct vm_area_struct *vma, unsigned long addr,
- pfn_t pfn)
+/*
+ * If the insertion of PTE failed because someone else already added a
+ * different entry in the mean time, we treat that as success as we assume
+ * the same entry was actually inserted.
+ */
+
+vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma,
+ unsigned long addr, pfn_t pfn)
{
- return __vm_insert_mixed(vma, addr, pfn, true);
+ int err;
+
+ err = __vm_insert_mixed(vma, addr, pfn, true);
+ if (err == -ENOMEM)
+ return VM_FAULT_OOM;
+ if (err < 0 && err != -EBUSY)
+ return VM_FAULT_SIGBUS;
+ return VM_FAULT_NOPAGE;
}
-EXPORT_SYMBOL(vm_insert_mixed_mkwrite);
+EXPORT_SYMBOL(vmf_insert_mixed_mkwrite);
/*
* maps a range of physical memory into the requested pages. the old