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[Qemu-devel] [PATCH 5/6] Move copy out of qemu_peek_buffer
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH 5/6] Move copy out of qemu_peek_buffer |
Date: |
Thu, 21 May 2015 13:24:15 +0100 |
From: "Dr. David Alan Gilbert" <address@hidden>
qemu_peek_buffer currently copies the data it reads into a buffer,
however a future patch wants access to the buffer without the copy,
hence rework to remove the copy to the layer above.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Amit Shah <address@hidden>
---
include/migration/qemu-file.h | 2 +-
migration/qemu-file.c | 12 +++++++-----
migration/vmstate.c | 5 +++--
3 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index 318aa1e..4f67d79 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -157,7 +157,7 @@ static inline void qemu_put_ubyte(QEMUFile *f, unsigned int
v)
void qemu_put_be16(QEMUFile *f, unsigned int v);
void qemu_put_be32(QEMUFile *f, unsigned int v);
void qemu_put_be64(QEMUFile *f, uint64_t v);
-int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset);
+int qemu_peek_buffer(QEMUFile *f, uint8_t **buf, int size, size_t offset);
int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size);
ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
int level);
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 0ef543a..965a757 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -349,14 +349,14 @@ void qemu_file_skip(QEMUFile *f, int size)
}
/*
- * Read 'size' bytes from file (at 'offset') into buf without moving the
- * pointer.
+ * Read 'size' bytes from file (at 'offset') without moving the
+ * pointer and set 'buf' to point to that data.
*
* It will return size bytes unless there was an error, in which case it will
* return as many as it managed to read (assuming blocking fd's which
* all current QEMUFile are)
*/
-int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset)
+int qemu_peek_buffer(QEMUFile *f, uint8_t **buf, int size, size_t offset)
{
int pending;
int index;
@@ -392,7 +392,7 @@ int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size,
size_t offset)
size = pending;
}
- memcpy(buf, f->buf + index, size);
+ *buf = f->buf + index;
return size;
}
@@ -411,11 +411,13 @@ int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size)
while (pending > 0) {
int res;
+ uint8_t *src;
- res = qemu_peek_buffer(f, buf, MIN(pending, IO_BUF_SIZE), 0);
+ res = qemu_peek_buffer(f, &src, MIN(pending, IO_BUF_SIZE), 0);
if (res == 0) {
return done;
}
+ memcpy(buf, src, res);
qemu_file_skip(f, res);
buf += res;
pending -= res;
diff --git a/migration/vmstate.c b/migration/vmstate.c
index e5388f0..a64ebcc 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -358,7 +358,7 @@ static int vmstate_subsection_load(QEMUFile *f, const
VMStateDescription *vmsd,
trace_vmstate_subsection_load(vmsd->name);
while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) {
- char idstr[256];
+ char idstr[256], *idstr_ret;
int ret;
uint8_t version_id, len, size;
const VMStateDescription *sub_vmsd;
@@ -369,11 +369,12 @@ static int vmstate_subsection_load(QEMUFile *f, const
VMStateDescription *vmsd,
trace_vmstate_subsection_load_bad(vmsd->name, "(short)");
return 0;
}
- size = qemu_peek_buffer(f, (uint8_t *)idstr, len, 2);
+ size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2);
if (size != len) {
trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)");
return 0;
}
+ memcpy(idstr, idstr_ret, size);
idstr[size] = 0;
if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) {
--
2.4.1
- [Qemu-devel] [PATCH 0/6] Migration cleanups for postcopy, Dr. David Alan Gilbert (git), 2015/05/21
- [Qemu-devel] [PATCH 1/6] Add qemu_get_counted_string to read a string prefixed by a count byte, Dr. David Alan Gilbert (git), 2015/05/21
- [Qemu-devel] [PATCH 2/6] Split header writing out of qemu_savevm_state_begin, Dr. David Alan Gilbert (git), 2015/05/21
- [Qemu-devel] [PATCH 3/6] qemu_ram_foreach_block: pass up error value, and down the ramblock name, Dr. David Alan Gilbert (git), 2015/05/21
- [Qemu-devel] [PATCH 4/6] Create MigrationIncomingState, Dr. David Alan Gilbert (git), 2015/05/21
- [Qemu-devel] [PATCH 5/6] Move copy out of qemu_peek_buffer,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH 6/6] Move loadvm_handlers into MigrationIncomingState, Dr. David Alan Gilbert (git), 2015/05/21