From 6b80f1d2cc5a76f0121a43a612515bc8a8976e66 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Sat, 23 Feb 2019 12:51:08 -0600 Subject: [PATCH] nvmet-fc: use zero-sized array and struct_size() in kzalloc() Update the code to use a zero-sized array instead of a pointer in structure nvmet_fc_tgt_queue and use struct_size() in kzalloc(). Notice that 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 foo { int stuff; struct boo entry[]; }; instance = kzalloc(sizeof(struct foo) + sizeof(struct boo) * count, 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, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva Reviewed-by: James Smart Signed-off-by: Christoph Hellwig --- drivers/nvme/target/fc.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c index 98b7b1f4ee96..9369a11fe7a9 100644 --- a/drivers/nvme/target/fc.c +++ b/drivers/nvme/target/fc.c @@ -128,12 +128,12 @@ struct nvmet_fc_tgt_queue { struct nvmet_cq nvme_cq; struct nvmet_sq nvme_sq; struct nvmet_fc_tgt_assoc *assoc; - struct nvmet_fc_fcp_iod *fod; /* array of fcp_iods */ struct list_head fod_list; struct list_head pending_cmd_list; struct list_head avail_defer_list; struct workqueue_struct *work_q; struct kref ref; + struct nvmet_fc_fcp_iod fod[]; /* array of fcp_iods */ } __aligned(sizeof(unsigned long long)); struct nvmet_fc_tgt_assoc { @@ -588,9 +588,7 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc, if (qid > NVMET_NR_QUEUES) return NULL; - queue = kzalloc((sizeof(*queue) + - (sizeof(struct nvmet_fc_fcp_iod) * sqsize)), - GFP_KERNEL); + queue = kzalloc(struct_size(queue, fod, sqsize), GFP_KERNEL); if (!queue) return NULL; @@ -603,7 +601,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc, if (!queue->work_q) goto out_a_put; - queue->fod = (struct nvmet_fc_fcp_iod *)&queue[1]; queue->qid = qid; queue->sqsize = sqsize; queue->assoc = assoc; -- 2.30.2