2015-07-10 15:42, Xie, Huawei: > Don't know why previous mail get messed.
Same problem with this one. It's maybe because you send HTML mail which is wrongly translated in plain text. > On 7/10/2015 10:50 PM, Pavel Boldin wrote: > Xie, > > Regarding the patches: > 1. The replaced code in fourth patch is checked to be a copy-paste of the > `sys_close` syscall. > > sys_close does extra cleanup than the replaced coe. My concern is, for > example, sys_close will mark the fd as next-to-be-allocated fd. Will there be > issue when we allocate a new fd, because it will be allocated starting from > the value of next-to-be-allocted-fd? I think kernel willn't blindly use that > value, but not sure. > > 2. It is not uncommon for the applications to close FD making it allocated > for a different file. In our particular case the file is closed in the > *source* process and *added* to a target process, so matching fds should not > be the problem. > > Yes, that is exactly what the old code does. > 3. There is an implementation of the exact same thing in the SCM_RIGHTS [1] > that can be used as the reference code. > > I did a rough check. Maybe i miss something. I see it calls fd_install on a > newly allocated fd. That is exactly what i want to replace the current code > with. > Currently we allcoate eventfd in user space and install a new file onto it > through fd_install. Actually we don't need to allocate the eventfd in user > space at all, what we should do is allocate a new fd in kernel, and install > the file onto it. > > new_fd = get_unused_fd_flags(...) > fd_install(new_fd, get_file(fp[i]) > > /huawei > > [1] https://github.com/torvalds/linux/blob/master/net/core/scm.c#L248 > > Pavel > > On Fri, Jul 10, 2015 at 5:27 PM, Xie, Huawei <huawei.xie at > intel.com<mailto:huawei.xie at intel.com>> wrote: > On 6/17/2015 11:24 PM, Thomas Monjalon wrote: > > 2015-05-07 06:54, Xie, Huawei: > >> On 4/16/2015 7:48 PM, Pavel Boldin wrote: > >>> + /* Closing the source_fd */ > >>> + ret = sys_close(eventfd_copy.source_fd); > >> Pavel: > >> Here we close the fd and re-install a new file on this fd later. > >> sys_close does all cleanup. > >> But, for instance, if we allocate new fd later, normally it will reuse > >> the just freed fds by sys_close, is there issue here? > > Pavel, Huawei, > > Could we come to a conclusion on this patch series please? > For the previous 3 patches, i am OK except that i don't think inline is > needed explicitly for non-performance critical function. > For this patch, didn't check the fs code. > > > > > > > >
