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Gustavo A. R. Silva
fae6cad17c
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 virtchnl_iwarp_qvlist_info {
...
struct virtchnl_iwarp_qv_info qv_info[1];
};
size = sizeof(struct virtchnl_iwarp_qvlist_info) + (sizeof(struct virtchnl_iwarp_qv_info) * count;
instance = kzalloc(size, GFP_KERNEL);
and
struct virtchnl_vf_resource {
...
struct virtchnl_vsi_resource vsi_res[1];
};
size = sizeof(struct virtchnl_vf_resource) + sizeof(struct virtchnl_vsi_resource) * 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, qv_info, count), GFP_KERNEL);
and
instance = kzalloc(struct_size(instance, vsi_res, count), GFP_KERNEL);
Notice that, in the first case above, variable 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>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.