mm: Define MAP_SYNC and VM_SYNC flags

Define new MAP_SYNC flag and corresponding VMA VM_SYNC flag. As the
MAP_SYNC flag is not part of LEGACY_MAP_MASK, currently it will be
refused by all MAP_SHARED_VALIDATE map attempts and silently ignored for
everything else.

Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 5589b4b..ea78b37 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -664,6 +664,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
                [ilog2(VM_ACCOUNT)]     = "ac",
                [ilog2(VM_NORESERVE)]   = "nr",
                [ilog2(VM_HUGETLB)]     = "ht",
+               [ilog2(VM_SYNC)]        = "sf",
                [ilog2(VM_ARCH_1)]      = "ar",
                [ilog2(VM_WIPEONFORK)]  = "wf",
                [ilog2(VM_DONTDUMP)]    = "dd",

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ca72b67..5411cb7 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -189,6 +189,7 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_ACCOUNT     0x00100000      /* Is a VM accounted object */
 #define VM_NORESERVE   0x00200000      /* should the VM suppress accounting */
 #define VM_HUGETLB     0x00400000      /* Huge TLB Page VM */
+#define VM_SYNC                0x00800000      /* Synchronous page faults */
 #define VM_ARCH_1      0x01000000      /* Architecture-specific flag */
 #define VM_WIPEONFORK  0x02000000      /* Wipe VMA contents in child. */
 #define VM_DONTDUMP    0x04000000      /* Do not include in the core dump */

diff --git a/include/linux/mman.h b/include/linux/mman.h
index 74452e3..3427bf3 100644 (file)
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -9,7 +9,7 @@
 
 /*
  * Arrange for legacy / undefined architecture specific flags to be
- * ignored by default in LEGACY_MAP_MASK.
+ * ignored by mmap handling code.
  */
 #ifndef MAP_32BIT
 #define MAP_32BIT 0
@@ -23,6 +23,9 @@
 #ifndef MAP_UNINITIALIZED
 #define MAP_UNINITIALIZED 0
 #endif
+#ifndef MAP_SYNC
+#define MAP_SYNC 0
+#endif
 
 /*
  * The historical set of flags that all mmap implementations implicitly
@@ -126,7 +129,8 @@ calc_vm_flag_bits(unsigned long flags)
 {
        return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
               _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
-              _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
+              _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
+              _calc_vm_trans(flags, MAP_SYNC,       VM_SYNC      );
 }
 
 unsigned long vm_commit_limit(void);

diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 7162cd4..00e5562 100644 (file)
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -12,6 +12,7 @@
 #define MAP_NONBLOCK   0x10000         /* do not block on IO */
 #define MAP_STACK      0x20000         /* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB    0x40000         /* create a huge page mapping */
+#define MAP_SYNC       0x80000         /* perform synchronous page faults for the mapping */
 
 /* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */