lkml.org 
[lkml]   [2019]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] nvmet-fc: use zero-sized array and struct_size() in kzalloc()
James, can you take a look at this one?

On Sat, Feb 23, 2019 at 12:51:08PM -0600, Gustavo A. R. Silva wrote:
> 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>
> ---
> 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 1e9654f04c60..23baec38f97e 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;
> --
> 2.20.1
---end quoted text---

\
 
 \ /
  Last update: 2019-03-08 14:27    [W:0.193 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site