From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Robert Moore <robert.moore@intel.com>,
Erik Schmauss <erik.schmauss@intel.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org, devel@acpica.org,
linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH] ACPICA: utids: Use struct_size() helper
Date: Wed, 5 Jun 2019 15:20:24 -0500 [thread overview]
Message-ID: <20190605202024.GA20848@embeddedor> (raw)
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 acpi_pnp_device_id_list {
...
struct acpi_pnp_device_id ids[1]; /* ID array */
};
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 acpi_pnp_device_id_list) + ((count - 1) * sizeof(struct acpi_pnp_device_id))
with:
struct_size(cid_list, ids, count - 1)
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
Notice that checkpatch reports the following warning:
WARNING: line over 80 characters
#54: FILE: drivers/acpi/acpica/utids.c:265:
+ cid_list_size = struct_size(cid_list, ids, count - 1) + string_area_size;
The line above is 81-character long. So, I think we should be fine
with that, instead of split it into two lines.
Thanks
Gustavo
drivers/acpi/acpica/utids.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/acpi/acpica/utids.c b/drivers/acpi/acpica/utids.c
index e805abdd95b8..737aa6a8f362 100644
--- a/drivers/acpi/acpica/utids.c
+++ b/drivers/acpi/acpica/utids.c
@@ -202,7 +202,7 @@ acpi_ut_execute_CID(struct acpi_namespace_node *device_node,
char *next_id_string;
u32 string_area_size;
u32 length;
- u32 cid_list_size;
+ size_t cid_list_size;
acpi_status status;
u32 count;
u32 i;
@@ -262,10 +262,7 @@ acpi_ut_execute_CID(struct acpi_namespace_node *device_node,
* 2) Size of the CID PNP_DEVICE_ID array +
* 3) Size of the actual CID strings
*/
- cid_list_size = sizeof(struct acpi_pnp_device_id_list) +
- ((count - 1) * sizeof(struct acpi_pnp_device_id)) +
- string_area_size;
-
+ cid_list_size = struct_size(cid_list, ids, count - 1) + string_area_size;
cid_list = ACPI_ALLOCATE_ZEROED(cid_list_size);
if (!cid_list) {
status = AE_NO_MEMORY;
--
2.21.0
reply other threads:[~2019-06-05 20:43 UTC|newest]
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