[libvirt] [PATCH 2/2] qemu: Remove unnecessary calculations in qemuDomainSaveMemory

[Peter Krempa]

Now that the file migration doesn't require us to use 'dd' and other
legacy stuff for too old qemus we don't even have to calcuate the
offsets and other stuff.
---
 src/qemu/qemu_driver.c  | 30 ++----------------------------
 src/qemu/qemu_monitor.h | 10 ----------
 2 files changed, 2 insertions(+), 38 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 77f4baa..2ca6700 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -3128,38 +3128,13 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,
     int directFlag = 0;
     virFileWrapperFdPtr wrapperFd = NULL;
     unsigned int wrapperFlags = VIR_FILE_WRAPPER_NON_BLOCKING;
-    unsigned long long pad;
-    unsigned long long offset;
-    size_t len;
-    char *xml = NULL;

     memset(&header, 0, sizeof(header));
     memcpy(header.magic, QEMU_SAVE_PARTIAL, sizeof(header.magic));
     header.version = QEMU_SAVE_VERSION;
     header.was_running = was_running ? 1 : 0;
-
     header.compressed = compressed;
-
-    len = strlen(domXML) + 1;
-    offset = sizeof(header) + len;
-
-    /* Due to way we append QEMU state on our header with dd,
-     * we need to ensure there's a 512 byte boundary. Unfortunately
-     * we don't have an explicit offset in the header, so we fake
-     * it by padding the XML string with NUL bytes.  Additionally,
-     * we want to ensure that virDomainSaveImageDefineXML can supply
-     * slightly larger XML, so we add a minimum padding prior to
-     * rounding out to page boundaries.
-     */
-    pad = 1024;
-    pad += (QEMU_MONITOR_MIGRATE_TO_FILE_BS -
-            ((offset + pad) % QEMU_MONITOR_MIGRATE_TO_FILE_BS));
-    if (VIR_ALLOC_N(xml, len + pad) < 0)
-        goto cleanup;
-    strcpy(xml, domXML);
-
-    offset += pad;
-    header.xml_len = len;
+    header.xml_len = strlen(domXML) + 1;

     /* Obtain the file handle.  */
     if ((flags & VIR_DOMAIN_SAVE_BYPASS_CACHE)) {
@@ -3184,7 +3159,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,
         goto cleanup;

     /* Write header to file, followed by XML */
-    if (qemuDomainSaveHeader(fd, path, xml, &header) < 0)
+    if (qemuDomainSaveHeader(fd, path, domXML, &header) < 0)
         goto cleanup;

     /* Perform the migration */
@@ -3226,7 +3201,6 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,
  cleanup:
     VIR_FORCE_CLOSE(fd);
     virFileWrapperFdFree(wrapperFd);
-    VIR_FREE(xml);

     if (ret < 0 && needUnlink)
         unlink(path);
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index d731344..134cbb6 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -560,16 +560,6 @@ int qemuMonitorMigrateToCommand(qemuMonitorPtr mon,
                                 unsigned int flags,
                                 const char * const *argv);

-/* In general, BS is the smallest fundamental block size we can use to
- * access a block device; everything must be aligned to a multiple of
- * this.  Linux generally supports a BS as small as 512, but with
- * newer disks with 4k sectors, performance is better if we guarantee
- * alignment to the sector size.  However, operating on BS-sized
- * blocks is painfully slow, so we also have a transfer size that is
- * larger but only aligned to the smaller block size.
- */
-# define QEMU_MONITOR_MIGRATE_TO_FILE_BS (1024llu * 4)
-
 int qemuMonitorMigrateToUnix(qemuMonitorPtr mon,
                              unsigned int flags,
                              const char *unixfile);
-- 
2.6.2