> https://github.com/ereshetova/linux-stable/commits/refcount_t_fs
Looking at "fs, cachefiles: convert cachefiles_object.usage from atomic_t to
refcount_t", I see:
- u = atomic_inc_return(&object->usage);
+ refcount_inc(&object->usage);
trace_cachefiles_ref(object, _object->cookie,
- (enum cachefiles_obj_ref_trace)why, u);
+ (enum cachefiles_obj_ref_trace)why,
refcount_read(&object->usage));
return &object->fscache;
This change is *not* equivalent. There's a reason I'm using
atomic_inc_return() and not atomic_inc(),atomic_read(). Yes, the small window
*does* occasionally produce incorrect tracing, and, yes, when that happens it
does make things confusing.
- u = atomic_dec_return(&object->usage);
trace_cachefiles_ref(object, _object->cookie,
- (enum cachefiles_obj_ref_trace)why, u);
- ASSERTCMP(u, !=, -1);
- if (u == 0) {
+ (enum cachefiles_obj_ref_trace)why,
refcount_read(&object->usage) - 1);
+ if (refcount_dec_and_test(&object->usage)) {
This is also not equivalent. Again, there's a reason I'm using
atomic_dec_return() and not atomic_read(),atomic_dec_and_test().
So, please drop the cachefiles/fscache patches or use refcount_inc_return()
and refcount_dec_return().
Another reason to please drop these patches is that they will cause my
fscache-iter branch to bounce. A lot of this code is deleted/heavily
rewritten:
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-iter
Thanks,
David
