[Qemu-devel] [PATCH V5_resend 2/7] util/mmap-alloc: switch qemu_ram_mmap() to 'flags' parameter

[Zhang Yi]

As more flag parameters besides the existing 'shared' are going to be
added to qemu_ram_mmap(), let's switch 'shared' to a 'flags' parameter
in advance, so as to ease the further additions.

Signed-off-by: Haozhong Zhang <address@hidden>
Signed-off-by: Zhang Yi <address@hidden>
---
 exec.c                    |  3 +--
 include/qemu/mmap-alloc.h | 19 ++++++++++++++++++-
 util/mmap-alloc.c         |  8 +++++---
 util/oslib-posix.c        |  4 +++-
 4 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/exec.c b/exec.c
index bb6170d..273f668 100644
--- a/exec.c
+++ b/exec.c
@@ -1859,8 +1859,7 @@ static void *file_ram_alloc(RAMBlock *block,
         perror("ftruncate");
     }
 
-    area = qemu_ram_mmap(fd, memory, block->mr->align,
-                         block->flags & RAM_SHARED);
+    area = qemu_ram_mmap(fd, memory, block->mr->align, block->flags);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
                          "unable to map backing store for guest RAM");
diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index 50385e3..6fe6ed4 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -7,7 +7,24 @@ size_t qemu_fd_getpagesize(int fd);
 
 size_t qemu_mempath_getpagesize(const char *mem_path);
 
-void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared);
+/**
+ * qemu_ram_mmap: mmap the specified file or device.
+ *
+ * Parameters:
+ *  @fd: the file or the device to mmap
+ *  @size: the number of bytes to be mmaped
+ *  @align: if not zero, specify the alignment of the starting mapping address;
+ *          otherwise, the alignment in use will be determined by QEMU.
+ *  @flags: specifies additional properties of the mapping, which can be one or
+ *          bit-or of following values
+ *          - RAM_SHARED: mmap with MAP_SHARED flag
+ *          Other bits are ignored.
+ *
+ * Return:
+ *  On success, return a pointer to the mapped area.
+ *  On failure, return MAP_FAILED.
+ */
+void *qemu_ram_mmap(int fd, size_t size, size_t align, uint32_t flags);
 
 void qemu_ram_munmap(void *ptr, size_t size);
 
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index fd329ec..8f0a740 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -13,6 +13,7 @@
 #include "qemu/osdep.h"
 #include "qemu/mmap-alloc.h"
 #include "qemu/host-utils.h"
+#include "exec/memory.h"
 
 #define HUGETLBFS_MAGIC       0x958458f6
 
@@ -75,7 +76,7 @@ size_t qemu_mempath_getpagesize(const char *mem_path)
     return getpagesize();
 }
 
-void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
+void *qemu_ram_mmap(int fd, size_t size, size_t align, uint32_t flags)
 {
     /*
      * Note: this always allocates at least one extra page of virtual address
@@ -92,11 +93,12 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool 
shared)
      * anonymous memory is OK.
      */
     int anonfd = fd == -1 || qemu_fd_getpagesize(fd) == getpagesize() ? -1 : 
fd;
-    int flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE;
-    void *ptr = mmap(0, total, PROT_NONE, flags | MAP_PRIVATE, anonfd, 0);
+    int mmap_flags = anonfd == -1 ? MAP_ANONYMOUS : MAP_NORESERVE;
+    void *ptr = mmap(0, total, PROT_NONE, mmap_flags | MAP_PRIVATE, anonfd, 0);
 #else
     void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 #endif
+    bool shared = flags & RAM_SHARED;
     size_t offset;
     void *ptr1;
 
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index fbd0dc8..c28869d 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -203,7 +203,9 @@ void *qemu_memalign(size_t alignment, size_t size)
 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
 {
     size_t align = QEMU_VMALLOC_ALIGN;
-    void *ptr = qemu_ram_mmap(-1, size, align, shared);
+    uint32_t flags = 0;
+    flags |= shared;
+    void *ptr = qemu_ram_mmap(-1, size, align, flags);
 
     if (ptr == MAP_FAILED) {
         return NULL;
-- 
2.7.4