nvmet-fc: use zero-sized array and struct_size() in kzalloc() (6b80f1d2) · Commits · 戴 / test

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 <gustavo@embeddedor.com> Reviewed-by:

James Smart <james.smart@broadcom.com> Signed-off-by:

Christoph Hellwig <hch@lst.de>

drivers/nvme/target/fc.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -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;

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