| Message ID | 85778a4619eab832eb0b003a68f377aea9d97b22.1554727307.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iommu: Fix offsetof() usage | expand |
> index 74e944bd4a8d..81d449451494 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1484,8 +1484,7 @@ static int arm_smmu_add_device(struct device *dev) > } > > ret = -ENOMEM; > - cfg = kzalloc(offsetof(struct arm_smmu_master_cfg, smendx[i]), > - GFP_KERNEL); > + cfg = kzalloc(struct_size(cfg, smendx, i), GFP_KERNEL); This looks like a huge improvement, but I find the usage of i here still very obsfucating. Can we please use fwspec->num_ids directly instead of make it much more obvious?
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 74e944bd4a8d..81d449451494 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1484,8 +1484,7 @@ static int arm_smmu_add_device(struct device *dev) } ret = -ENOMEM; - cfg = kzalloc(offsetof(struct arm_smmu_master_cfg, smendx[i]), - GFP_KERNEL); + cfg = kzalloc(struct_size(cfg, smendx, i), GFP_KERNEL); if (!cfg) goto out_free; diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 33a982e33716..ad28919e1452 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2021,7 +2021,7 @@ int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids) if (!fwspec) return -EINVAL; - size = offsetof(struct iommu_fwspec, ids[fwspec->num_ids + num_ids]); + size = struct_size(fwspec, ids, fwspec->num_ids + num_ids); if (size > sizeof(*fwspec)) { fwspec = krealloc(fwspec, size, GFP_KERNEL); if (!fwspec)
David rightly points out that, although GCC lets us get away with it, using offsetof() with a non-constant member designator is not compliant with the C standard. I'm responsible for a couple of those misuses, but both in circumstances for which we now have a specific helper, so we can use that to put things straight. Suggested-by: David Laight <David.Laight@ACULAB.COM> Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- drivers/iommu/arm-smmu.c | 3 +-- drivers/iommu/iommu.c | 2 +- 2 files changed, 2 insertions(+), 3 deletions(-)