lib: objagg: Use the bitmap API when applicable

Use 'bitmap_zalloc()' to simplify code, improve the semantic and reduce
some open-coded arithmetic in allocator arguments.

Also change the correspond

lib: objagg: Use the bitmap API when applicable

Use 'bitmap_zalloc()' to simplify code, improve the semantic and reduce
some open-coded arithmetic in allocator arguments.

Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/f9541b085ec68e573004e1be200c11c9c901181a.1640295165.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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lib: objagg: Replace zero-length arrays with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to decl

lib: objagg: Replace zero-length arrays with flexible-array member

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>

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lib: objagg: Use struct_size() in kzalloc()

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

lib: objagg: Use struct_size() in kzalloc()

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>

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lib: objagg: fix handling of object with 0 users when assembling hints

It is possible that there might be an originally parent object with 0
direct users that is in hints no longer considered as par

lib: objagg: fix handling of object with 0 users when assembling hints

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>

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lib: objagg: Fix an error code in objagg_hints_get()

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: 9069a38

lib: objagg: Fix an error code in objagg_hints_get()

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>

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lib: objagg: add root count to stats

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.

Si

lib: objagg: add root count to stats

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>

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lib: objagg: implement optimization hints assembly and use hints for object creation

Implement simple greedy algo to find more optimized root-delta tree for
a given objagg instance. This "hints" can

lib: objagg: implement optimization hints assembly and use hints for object 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>

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lib: objagg: fix typo in objagg_stats_put() docstring

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.

lib: objagg: fix typo in objagg_stats_put() docstring

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>

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lib: introduce initial implementation of object aggregation manager

This lib tracks objects which could be of two types:
1) root object
2) nested object - with a "delta" which differentiates it from

lib: introduce initial implementation of object aggregation manager

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>

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