Re: [Qemu-devel] [PATCH v4 4/4] Clear handler only for valid fd

[Orit Wasserman]

On 09/24/2012 11:45 AM, Markus Armbruster wrote:
> Orit Wasserman <address@hidden> writes:
> 
>> Signed-off-by: Orit Wasserman <address@hidden>
>> ---
>>  migration.c |    3 +--
>>  1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/migration.c b/migration.c
>> index 1edeec5..c20a2fe 100644
>> --- a/migration.c
>> +++ b/migration.c
>> @@ -240,8 +240,6 @@ static int migrate_fd_cleanup(MigrationState *s)
>>  {
>>      int ret = 0;
>>  
>> -    qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
>> -
>>      if (s->file) {
>>          DPRINTF("closing file\n");
>>          ret = qemu_fclose(s->file);
>> @@ -249,6 +247,7 @@ static int migrate_fd_cleanup(MigrationState *s)
>>      }
>>  
>>      if (s->fd != -1) {
>> +        qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
>>          close(s->fd);
>>          s->fd = -1;
>>      }
> 
> As far as I can see, qemu_set_fd_handler2() treats invalid file
> descriptor -1 just like any other.  If it's in io_handlers, it gets
> deleted, else it's a nop.  Thus, the old code works.
Not any more, there was an assert(fd >=0) added in commit 
bbdd2ad0814ea0911076419ea21b7957505cf1cc
recently.

  But I agree
> passing invalid file descriptors is abusing the interface.
> 
> I'm not sufficiently familiar with the migration code to judge whether
> moving the handler reset down is safe.
> 
I can keep the call in the same location if you think it is safer.

Orit