Hi Andrea, On 2018/11/23 17:51, Andrea Parri wrote: > Correct. This is informally documented in Documentation/atomic_t.txt > and formalized within tools/memory-model/. > > >> I don't know whether my understanding is correct, If I am wrong..please correct me, or >> I need to add more detailed code comments to explain in the code? > Yes, please; please review the above points (including 1. and 3.) and > try to address them with inline comments. Maybe (if that matches the > *behavior*/guarantee you have in mind...) something like: > > [in erofs_workgroup_unfreeze()] > > /* > * Orders the store/load to/from [???] and the store to > * ->refcount performed by the atomic_set() below. > * > * Matches the atomic_cmpxchg() in erofs_workgroup_get(). > * > * Guarantees that if a successful atomic_cmpxchg() reads > * the value stored by the atomic_set() then [???]. > */ > smp_mb(); > atomic_set(&grp->refcount, v); > > > [in erofs_workgroup_get()] > > /* > * Orders the load from ->refcount performed by the > * atomic_cmpxchg() below and the store/load [???]. > * > * See the comment for the smp_mb() in > * erofs_workgroup_unfreeze(). > */ > if (unlikely(atomic_cmpxchg(&grp->refcount, o, o + 1) != o)) > goto repeat; > OK, I will add these comments in the next version patchset, will be sent later. Thanks for your suggestion. :) Thanks, Gao Xiang > Thanks, > Andrea > > _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
