On 2019/2/25 23:04, Greg Kroah-Hartman wrote: > On Wed, Feb 20, 2019 at 05:18:48PM +0800, Gao Xiang wrote: >> commit 51232df5e4b268936beccde5248f312a316800be upstream. >> >> When the managed cache is enabled, the last reference count >> of a workgroup must be used for its workstation. >> >> Otherwise, it could lead to incorrect (un)freezes in >> the reclaim path, and it would be harmful. >> >> A typical race as follows: >> >> Thread 1 (In the reclaim path) Thread 2 >> workgroup_freeze(grp, 1) refcnt = 1 >> ... >> workgroup_unfreeze(grp, 1) refcnt = 1 >> workgroup_get(grp) refcnt = 2 (x) >> workgroup_put(grp) refcnt = 1 (x) >> ...unexpected behaviors >> >> * grp is detached but still used, which violates cache-managed >> freeze constraint. >> >> Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx> >> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx> >> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> >> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx> >> >> Conflicts: >> drivers/staging/erofs/utils.c >> Updates: >> include/linux/xarray.h: >> add xa_untag_pointer,xa_tag_pointer,xa_pointer_tag >> from upstream 3159f943aafd in order to reduce >> conflicts. > > No, sorry, I don't want to add xarray.h to 4.19.y, that's crazy. Or can I define these xa_untag_pointer,xa_tag_pointer,xa_pointer_tag in a erofs header internally? it is acceptable? Thanks, Gao Xiang > > And even if we did, you do not slip it in as part of a different patch, > it should come in as its own patch, with the same git commit id that it > landed in 4.20 with. > > Please fix this up... > > greg k-h >
