net/mlx4: avoid GCC 10 __bad_copy_from() false positive

mlx4_init_user_cqes() fills a scratch buffer with the CQE
initialization pattern and then copies from that buffer to userspace.

In the single-copy path, the copy length is array_size(entries,
cqe_size), but the scratch buffer is allocated with PAGE_SIZE. GCC 10
does not carry the branch invariant strongly enough through the object
size checks and falsely triggers __bad_copy_from().

Size the scratch buffer to the actual copy length for the active path,
keep array_size() for the single-copy case, and retain a WARN_ON_ONCE()
guard for the PAGE_SIZE invariant before allocating the buffer.

Fixes: f69bf5dee7ef ("net/mlx4: Use array_size() helper in copy_to_user()")
Signed-off-by: Yao Sang <sangyao@kylinos.cn>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions