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| author | Souptick Joarder <jrdr.linux@gmail.com> | 2018-05-26 14:15:09 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2018-05-26 14:29:02 +1000 |
| commit | aa726309bde72fe5081cf5422ad5142f8e527e71 (patch) | |
| tree | 78eb109bb0dbf0610f20e9cba52ad897ecc1084c /mm | |
| parent | b0bad9e1a49288d6f09d530e1948d803dc8970ca (diff) | |
| download | linux-next-aa726309bde72fe5081cf5422ad5142f8e527e71.tar.gz | |
fs/dax.c: add 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: Stephen Rothwell <sfr@canb.auug.org.au>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 21 |
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 |