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[Qemu-devel] [PATCH v2 4/4] util/mmap-alloc: account for DAX device in q
From: |
Haozhong Zhang |
Subject: |
[Qemu-devel] [PATCH v2 4/4] util/mmap-alloc: account for DAX device in qemu_fd_getpagesize |
Date: |
Tue, 6 Jun 2017 15:22:29 +0800 |
A DAX device may require a page size different than getpagesize().
Signed-off-by: Haozhong Zhang <address@hidden>
---
include/qemu/osdep.h | 10 ++++++++++
util/mmap-alloc.c | 6 ++++++
util/osdep.c | 23 +++++++++++++++++++++++
3 files changed, 39 insertions(+)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 7f26af371e..51aca88f0d 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -479,4 +479,14 @@ pid_t qemu_fork(Error **errp);
*/
bool qemu_fd_is_dev_dax(int fd);
+/**
+ * qemu_get_dev_dax_align:
+ *
+ * Get the suggested alignment of a DAX device descried by @fd.
+ *
+ * Return a non-zero suggested alignment on success; return 0 if @fd
+ * does not describe a DAX device, or if it fails to get alignment
+ * of the DAX device.
+ */
+size_t qemu_get_dev_dax_align(int fd);
#endif
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 3ec029a9ea..2d8af64b44 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -25,8 +25,14 @@ size_t qemu_fd_getpagesize(int fd)
#ifdef CONFIG_LINUX
struct statfs fs;
int ret;
+ size_t align;
if (fd != -1) {
+ align = qemu_get_dev_dax_align(fd);
+ if (align) {
+ return align;
+ }
+
do {
ret = fstatfs(fd, &fs);
} while (ret != 0 && errno == EINTR);
diff --git a/util/osdep.c b/util/osdep.c
index 02881f96bc..e7837d30b4 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -532,3 +532,26 @@ bool qemu_fd_is_dev_dax(int fd)
return is_dax;
}
+
+size_t qemu_get_dev_dax_align(int fd)
+{
+ size_t align = 0;
+
+#ifdef __linux__
+ char buf[12];
+ ssize_t len;
+
+ if (!qemu_fd_is_dev_dax(fd)) {
+ return 0;
+ }
+ len = qemu_dev_dax_sysfs_read(fd, "device/align", buf, sizeof(buf));
+ if (len <= 0) {
+ return 0;
+ }
+ if (qemu_strtosz(buf, NULL, &align) < 0) {
+ align = 0;
+ }
+#endif /* __linux__ */
+
+ return align;
+}
--
2.11.0