From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: James Smart <james.smart@broadcom.com>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH] nvmet-fc: use zero-sized array and struct_size() in kzalloc()
Date: Sat, 23 Feb 2019 12:51:08 -0600 [thread overview]
Message-ID: <20190223185108.GA6706@embeddedor> (raw)
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
next reply other threads:[~2019-02-23 18:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-23 18:51 Gustavo A. R. Silva [this message]
2019-02-23 20:05 ` [PATCH] nvmet-fc: use zero-sized array and struct_size() in kzalloc() Joe Perches
2019-02-23 20:28 ` Gustavo A. R. Silva
2019-02-24 1:34 ` Gustavo A. R. Silva
2019-03-08 13:27 ` Christoph Hellwig
2019-03-08 19:15 ` James Smart
2019-03-12 19:33 ` Christoph Hellwig
2019-03-12 19:47 ` Gustavo A. R. Silva
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