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[Qemu-devel] [PATCH v4 09/33] exec: allow file_ram_alloc to work on file
From: |
Xiao Guangrong |
Subject: |
[Qemu-devel] [PATCH v4 09/33] exec: allow file_ram_alloc to work on file |
Date: |
Mon, 19 Oct 2015 08:53:55 +0800 |
Currently, file_ram_alloc() only works on directory - it creates a file
under @path and do mmap on it
This patch tries to allow it to work on file directly, if @path is a
directory it works as before, otherwise it treats @path as the target
file then directly allocate memory from it
Signed-off-by: Xiao Guangrong <address@hidden>
---
exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------
1 file changed, 51 insertions(+), 29 deletions(-)
diff --git a/exec.c b/exec.c
index d2a3357..09e9938 100644
--- a/exec.c
+++ b/exec.c
@@ -1157,14 +1157,60 @@ void qemu_mutex_unlock_ramlist(void)
}
#ifdef __linux__
+static bool path_is_dir(const char *path)
+{
+ struct stat fs;
+
+ return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode);
+}
+
+static int open_file_path(RAMBlock *block, const char *path, size_t size)
+{
+ char *filename;
+ char *sanitized_name;
+ char *c;
+ int fd;
+
+ if (!path_is_dir(path)) {
+ int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY;
+
+ flags |= O_EXCL;
+ return open(path, flags);
+ }
+
+ /* Make name safe to use with mkstemp by replacing '/' with '_'. */
+ sanitized_name = g_strdup(memory_region_name(block->mr));
+ for (c = sanitized_name; *c != '\0'; c++) {
+ if (*c == '/') {
+ *c = '_';
+ }
+ }
+ filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path,
+ sanitized_name);
+ g_free(sanitized_name);
+ fd = mkstemp(filename);
+ if (fd >= 0) {
+ unlink(filename);
+ /*
+ * ftruncate is not supported by hugetlbfs in older
+ * hosts, so don't bother bailing out on errors.
+ * If anything goes wrong with it under other filesystems,
+ * mmap will fail.
+ */
+ if (ftruncate(fd, size)) {
+ perror("ftruncate");
+ }
+ }
+ g_free(filename);
+
+ return fd;
+}
+
static void *file_ram_alloc(RAMBlock *block,
ram_addr_t memory,
const char *path,
Error **errp)
{
- char *filename;
- char *sanitized_name;
- char *c;
void *area;
int fd;
uint64_t pagesize;
@@ -1194,38 +1240,14 @@ static void *file_ram_alloc(RAMBlock *block,
goto error;
}
- /* Make name safe to use with mkstemp by replacing '/' with '_'. */
- sanitized_name = g_strdup(memory_region_name(block->mr));
- for (c = sanitized_name; *c != '\0'; c++) {
- if (*c == '/')
- *c = '_';
- }
-
- filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path,
- sanitized_name);
- g_free(sanitized_name);
+ memory = ROUND_UP(memory, pagesize);
- fd = mkstemp(filename);
+ fd = open_file_path(block, path, memory);
if (fd < 0) {
error_setg_errno(errp, errno,
"unable to create backing store for path %s", path);
- g_free(filename);
goto error;
}
- unlink(filename);
- g_free(filename);
-
- memory = ROUND_UP(memory, pagesize);
-
- /*
- * ftruncate is not supported by hugetlbfs in older
- * hosts, so don't bother bailing out on errors.
- * If anything goes wrong with it under other filesystems,
- * mmap will fail.
- */
- if (ftruncate(fd, memory)) {
- perror("ftruncate");
- }
area = qemu_ram_mmap(fd, memory, pagesize, block->flags & RAM_SHARED);
if (area == MAP_FAILED) {
--
1.8.3.1
- [Qemu-devel] [PATCH v4 04/33] acpi: add aml_concatenate, (continued)
- [Qemu-devel] [PATCH v4 04/33] acpi: add aml_concatenate, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 02/33] acpi: add aml_sizeof, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 05/33] acpi: add aml_object_type, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 06/33] acpi: add aml_method_serialized, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 03/33] acpi: add aml_create_field, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 01/33] acpi: add aml_derefof, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 07/33] util: introduce qemu_file_get_page_size(), Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 10/33] hostmem-file: clean up memory allocation, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 08/33] exec: allow memory to be allocated from any kind of path, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 11/33] hostmem-file: use whole file size if possible, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 09/33] exec: allow file_ram_alloc to work on file,
Xiao Guangrong <=
- [Qemu-devel] [PATCH v4 12/33] pc-dimm: remove DEFAULT_PC_DIMMSIZE, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 13/33] pc-dimm: make pc_existing_dimms_capacity static and rename it, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 15/33] stubs: rename qmp_pc_dimm_device_list.c, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 14/33] pc-dimm: drop the prefix of pc-dimm, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 16/33] pc-dimm: rename pc-dimm.c and pc-dimm.h, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 17/33] dimm: abstract dimm device from pc-dimm, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 18/33] dimm: get mapped memory region from DIMMDeviceClass->get_memory_region, Xiao Guangrong, 2015/10/18
- [Qemu-devel] [PATCH v4 19/33] dimm: keep the state of the whole backend memory, Xiao Guangrong, 2015/10/18