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 qat_alg_buf_list {
        ...
        struct qat_alg_buf bufers[];
} __packed __aligned(64);

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(struct qat_alg_buf_list) + ((1 + n) * sizeof(struct qat_alg_buf))

with:

struct_size(bufl, bufers, n + 1)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com>
---
 drivers/crypto/qat/qat_common/qat_algs.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/qat/qat_common/qat_algs.c 
b/drivers/crypto/qat/qat_common/qat_algs.c
index 2842b2cdaa90..b50eb55f8f57 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -717,8 +717,7 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance 
*inst,
        dma_addr_t blp;
        dma_addr_t bloutp = 0;
        struct scatterlist *sg;
-       size_t sz_out, sz = sizeof(struct qat_alg_buf_list) +
-                       ((1 + n) * sizeof(struct qat_alg_buf));
+       size_t sz_out, sz = struct_size(bufl, bufers, n + 1);
 
        if (unlikely(!n))
                return -EINVAL;
@@ -755,8 +754,7 @@ static int qat_alg_sgl_to_bufl(struct qat_crypto_instance 
*inst,
                struct qat_alg_buf *bufers;
 
                n = sg_nents(sglout);
-               sz_out = sizeof(struct qat_alg_buf_list) +
-                       ((1 + n) * sizeof(struct qat_alg_buf));
+               sz_out = struct_size(buflout, bufers, n + 1);
                sg_nctr = 0;
                buflout = kzalloc_node(sz_out, GFP_ATOMIC,
                                       dev_to_node(&GET_DEV(inst->accel_dev)));
-- 
2.21.0

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