glusterfs.git/libglusterfs/src/refcount.h, branch v3.12.5

multiple: fix struct/typedef inconsistencies

2017-06-30T10:31:02+00:00

The most common pattern, both in our code and elsewhere, is this:

   struct _xyz {
      ...
   };
   typedef struct _xyz xyz_t;

These exceptions - especially call_frame/call_stack - have been slowing
down code navigation for years.  By converging on a single pattern,
navigating from xyz_t in code to the actual definition of struct _xyz
(i.e. without having to visit the typedef first) might even be
automatable.

Change-Id: I0e5dd1f51f98e000173c62ef4ddc5b21d9ec44ed
Signed-off-by: Jeff Darcy 
Reviewed-on: https://review.gluster.org/17650
Smoke: Gluster Build System 
Tested-by: Jeff Darcy 
CentOS-regression: Gluster Build System 
Reviewed-by: Amar Tumballi 
Reviewed-by: Niels de Vos

refcount: correct the return value of GF_REF_PUT()

2017-03-22T01:00:17+00:00

It is documented that GF_REF_PUT() returns a 0 in case the call resulted
in free'ing the structure. However the implementations did not have a
return value, so nothing can actually use it.

Change-Id: Ic57091f5ddd7e0b80929dc335a5b6d37f5fe1b2e
BUG: 1433405
Signed-off-by: Niels de Vos 
Reviewed-on: https://review.gluster.org/16910
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Xavier Hernandez 
Reviewed-by: Jeff Darcy 
Reviewed-by: Kaleb KEITHLEY

refcount: typecast function for calling on free

2017-01-31T05:04:44+00:00

All of the functions called to free the refcounted structure are doing a
typecast from (void*) to their own type taht is being free'd. This
really is not needed and the refcount interface is made a little simpler
without the requirement of typecasting.

With this small improvement in the API, all callers are updated too.

Change-Id: I32473b6d1799f62861d4b2d78ea30c09e6c80ab1
BUG: 1416889
Signed-off-by: Niels de Vos 
Reviewed-on: https://review.gluster.org/16471
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Xavier Hernandez 
CentOS-regression: Gluster Build System 
Reviewed-by: Kaleb KEITHLEY

refcount: return pointer to the structure instead of a counter

2016-12-11T08:47:05+00:00

There are no real users of the counter. It was thought of a handy tool
to track and debug refcounting, but it is not used at all. Some parts of
the code would benefit from a pointer getting returned instead.

BUG: 1399780
Change-Id: I97e52c48420fed61be942ea27ff4849b803eed12
Signed-off-by: Niels de Vos 
Reviewed-on: http://review.gluster.org/15971
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Xavier Hernandez 
Reviewed-by: Kaleb KEITHLEY

refcount: correct the documentation

2015-06-21T13:14:27+00:00

The only check that _gf_ref_get() needs is "== 0" for detecting a
failure. The actual return value is not guaranteed to be the number of
active refences (they can change in other threads anyway).

BUG: 1163543
Change-Id: I8801601eab37046f5a5ee0bce5a62606115ca151
Signed-off-by: Niels de Vos 
Reviewed-on: http://review.gluster.org/11328
Tested-by: NetBSD Build System 
Tested-by: Gluster Build System 
Reviewed-by: Kaleb KEITHLEY

core: add "gf_ref_t" for common refcounting structures

2015-06-20T12:01:43+00:00

Checks for compiler supported atomic operations comes from client_t.h.

An example usage of this change can be found in adding reference
counting to "struct auth_cache_entry" in http://review.gluster.org/11023

Basic usage looks like this:

   #include "refcount.h"

   struct my_struct {
       GF_REF_DECL;
       ... /* more members */
   }

   void my_destructor (void *data)
   {
       struct my_struct *my_ptr = (struct my_struct *) data;

       ... /* do some more cleanups */
       GF_FREE (my_ptr);
   }

   void init_ptr (struct parent *parent)
   {
       struct my_struct *my_ptr = malloc (sizeof (struct my_struct));

       GF_REF_INIT (my_ptr, my_destructor); /* refcount is set to 1 */

       ... /* my_ptr probably gets added to some parent structure */
       parent_add_ptr (parent, my_ptr);
   }

   void do_something (struct parent *parent)
   {
       struct my_struct *my_ptr = NULL;

       /* likely need to lock parent, depends on its access pattern */
       my_ptr = parent_remove_first_ptr (parent);
       /* unlock parent */

       ... /* do something */

       GF_REF_PUT (my_ptr); /* calls my_destructor on refcount = 0 */
   }

URL: http://thread.gmane.org/gmane.comp.file-systems.gluster.devel/11202
Change-Id: Idb98a5861a44c31676108ed8876db12c320912ef
BUG: 1228157
Signed-off-by: Niels de Vos 
Reviewed-on: http://review.gluster.org/11022
Reviewed-by: Xavier Hernandez 
Reviewed-by: Krishnan Parthasarathi 
Tested-by: Gluster Build System 
Tested-by: NetBSD Build System