| Message ID | 20200929190156.GA25604@embeddedor |
|---|---|
| State | New |
| Headers | show |
| Series | [next] ice: Replace one-element array with flexible-array member | expand |
diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h index 65583f0a1797..a4c84faa36d6 100644 --- a/drivers/net/ethernet/intel/ice/ice.h +++ b/drivers/net/ethernet/intel/ice/ice.h @@ -164,7 +164,7 @@ struct ice_tc_cfg { struct ice_res_tracker { u16 num_entries; u16 end; - u16 list[1]; + u16 list[]; }; struct ice_qs_cfg { diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index 2297ee7dba26..f6a7a23615eb 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -3500,9 +3500,9 @@ static int ice_init_interrupt_scheme(struct ice_pf *pf) return vectors; /* set up vector assignment tracking */ - pf->irq_tracker = - devm_kzalloc(ice_pf_to_dev(pf), sizeof(*pf->irq_tracker) + - (sizeof(u16) * vectors), GFP_KERNEL); + pf->irq_tracker = devm_kzalloc(ice_pf_to_dev(pf), + struct_size(pf->irq_tracker, list, vectors), + GFP_KERNEL); if (!pf->irq_tracker) { ice_dis_msix(pf); return -ENOMEM;
There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Refactor the code according to the use of a flexible-array member in struct ice_res_tracker, instead of a one-element array and use the struct_size() helper to calculate the size for the allocations. Also, notice that the code below suggests that, currently, two too many bytes are being allocated with devm_kzalloc(), as the total number of entries (pf->irq_tracker->num_entries) for pf->irq_tracker->list[] is _vectors_ and sizeof(*pf->irq_tracker) also includes the size of the one-element array _list_ in struct ice_res_tracker. drivers/net/ethernet/intel/ice/ice_main.c:3511: 3511 /* populate SW interrupts pool with number of OS granted IRQs. */ 3512 pf->num_avail_sw_msix = (u16)vectors; 3513 pf->irq_tracker->num_entries = (u16)vectors; 3514 pf->irq_tracker->end = pf->irq_tracker->num_entries; With this change, the right amount of dynamic memory is now allocated because, contrary to one-element arrays which occupy at least as much space as a single object of the type, flexible-array members don't occupy such space in the containing structure. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays Built-tested-by: kernel test robot <lkp@intel.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- drivers/net/ethernet/intel/ice/ice.h | 2 +- drivers/net/ethernet/intel/ice/ice_main.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-)