[Qemu-devel] [PATCH 2/3] exec: adjuest rcu_read_lock requiement

[Gonglei]

qemu_ram_unset_idstr() don't need rcu lock anymore,
meanwhile adjuest the range of rcu lock in
qemu_ram_set_idstr() as small as possible.

Signed-off-by: Gonglei <arei.gong...@huawei.com>
---
 exec.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/exec.c b/exec.c
index 101f0f4..b0ecbcd 100644
--- a/exec.c
+++ b/exec.c
@@ -1418,8 +1418,6 @@ void qemu_ram_set_idstr(RAMBlock *block, const char 
*name, DeviceState *dev)
     RAMBlock *new_block = block;
     RAMBlock *old_block;
 
-    rcu_read_lock();
-
     assert(new_block);
     assert(!new_block->idstr[0]);
 
@@ -1432,6 +1430,7 @@ void qemu_ram_set_idstr(RAMBlock *block, const char 
*name, DeviceState *dev)
     }
     pstrcat(new_block->idstr, sizeof(new_block->idstr), name);
 
+    rcu_read_lock();
     QLIST_FOREACH_RCU(old_block, &ram_list.blocks, next) {
         if (old_block != new_block &&
             !strcmp(old_block->idstr, new_block->idstr)) {
@@ -1443,7 +1442,6 @@ void qemu_ram_set_idstr(RAMBlock *block, const char 
*name, DeviceState *dev)
     rcu_read_unlock();
 }
 
-/* Called with iothread lock held.  */
 void qemu_ram_unset_idstr(RAMBlock *block)
 {
     /* FIXME: arch_init.c assumes that this is not called throughout
@@ -1451,11 +1449,9 @@ void qemu_ram_unset_idstr(RAMBlock *block)
      * does not work anyway.
      */
 
-    rcu_read_lock();
     if (block) {
         memset(block->idstr, 0, sizeof(block->idstr));
     }
-    rcu_read_unlock();
 }
 
 static int memory_try_enable_merging(void *addr, size_t len)
-- 
1.7.12.4