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2020-02-16lib: objagg: Replace zero-length arrays with flexible-array memberGustavo A. R. Silva
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertenly introduced[3] to the codebase from now on. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-05lib: objagg: Use struct_size() in kzalloc()Gustavo A. R. Silva
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct objagg_stats { ... struct objagg_obj_stats_info stats_info[]; }; size = sizeof(*objagg_stats) + sizeof(objagg_stats->stats_info[0]) * count; instance = kzalloc(size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc(struct_size(instance, stats_info, count), GFP_KERNEL); Notice that, in this case, variable alloc_size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-14lib: objagg: fix handling of object with 0 users when assembling hintsJiri Pirko
It is possible that there might be an originally parent object with 0 direct users that is in hints no longer considered as parent. Then the weight of this object is 0 and current code ignores him. That's why the total amount of hint objects might be lower than for the original objagg and WARN_ON is hit. Fix this be considering 0 weight valid. Fixes: 9069a3817d82 ("lib: objagg: implement optimization hints assembly and use hints for object creation") Signed-off-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-13lib: objagg: Fix an error code in objagg_hints_get()Dan Carpenter
We need to set the error code on this path otherwise we return ERR_PTR(0) which would result in a NULL dereference in the caller. Fixes: 9069a3817d82 ("lib: objagg: implement optimization hints assembly and use hints for object creation") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-08lib: objagg: add root count to statsJiri Pirko
Count number of roots and add it to stats. It is handy for the library user to have this stats available as it can act upon it without counting roots itself. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-08lib: objagg: implement optimization hints assembly and use hints for object ↵Jiri Pirko
creation Implement simple greedy algo to find more optimized root-delta tree for a given objagg instance. This "hints" can be used by a driver to: 1) check if the hints are better (driver's choice) than the original objagg tree. Driver does comparison of objagg stats and hints stats. 2) use the hints to create a new objagg instance which will construct the root-delta tree according to the passed hints. Currently, only a simple greedy algorithm is implemented. Basically it finds the roots according to the maximal possible user count including deltas. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-08lib: objagg: fix typo in objagg_stats_put() docstringJiri Pirko
Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-15lib: introduce initial implementation of object aggregation managerJiri Pirko
This lib tracks objects which could be of two types: 1) root object 2) nested object - with a "delta" which differentiates it from the associated root object The objects are tracked by a hashtable and reference-counted. User is responsible of implementing callbacks to create/destroy root entity related to each root object and callback to create/destroy nested object delta. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>