overflow: Add struct_size_t() helper

While struct_size() is normally used in situations where the structure
type already has a pointer instance, there are places where no variable
is available. In the past, this has been worked around by using a typed
NULL first argument, but this is a bit ugly. Add a helper to do this,
and replace the handful of instances of the code pattern with it.

Instances were found with this Coccinelle script:

@struct_size_t@
identifier STRUCT, MEMBER;
expression COUNT;
@@

-       struct_size((struct STRUCT *)\(0\|NULL\),
+       struct_size_t(struct STRUCT,
                MEMBER, COUNT)

Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: HighPoint Linux Team <linux@highpoint-tech.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Cc: Don Brace <don.brace@microchip.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Guo Xuenan <guoxuenan@huawei.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: kernel test robot <lkp@intel.com>
Cc: intel-wired-lan@lists.osuosl.org
Cc: netdev@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: linux-scsi@vger.kernel.org
Cc: megaraidlinux.pdl@broadcom.com
Cc: storagedev@microchip.com
Cc: linux-xfs@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20230522211810.never.421-kees@kernel.org

2 files changed, 9 insertions, 9 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 317c944c68e3..050eed8e2684 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -5153,8 +5153,8 @@ static void megasas_update_ext_vd_details(struct megasas_instance *instance)
 		fusion->max_map_sz = ventura_map_sz;
 	} else {
 		fusion->old_map_sz =
-			struct_size((struct MR_FW_RAID_MAP *)0, ldSpanMap,
-				    instance->fw_supported_vd_count);
+			struct_size_t(struct MR_FW_RAID_MAP, ldSpanMap,
+				      instance->fw_supported_vd_count);
 		fusion->new_map_sz =  sizeof(struct MR_FW_RAID_MAP_EXT);
 
 		fusion->max_map_sz =
@@ -5789,8 +5789,8 @@ megasas_setup_jbod_map(struct megasas_instance *instance)
 	struct fusion_context *fusion = instance->ctrl_context;
 	size_t pd_seq_map_sz;
 
-	pd_seq_map_sz = struct_size((struct MR_PD_CFG_SEQ_NUM_SYNC *)0, seq,
-				    MAX_PHYSICAL_DEVICES);
+	pd_seq_map_sz = struct_size_t(struct MR_PD_CFG_SEQ_NUM_SYNC, seq,
+				      MAX_PHYSICAL_DEVICES);
 
 	instance->use_seqnum_jbod_fp =
 		instance->support_seqnum_jbod_fp;
@@ -8033,8 +8033,8 @@ skip_firing_dcmds:
 	if (instance->adapter_type != MFI_SERIES) {
 		megasas_release_fusion(instance);
 		pd_seq_map_sz =
-			struct_size((struct MR_PD_CFG_SEQ_NUM_SYNC *)0,
-				    seq, MAX_PHYSICAL_DEVICES);
+			struct_size_t(struct MR_PD_CFG_SEQ_NUM_SYNC,
+				      seq, MAX_PHYSICAL_DEVICES);
 		for (i = 0; i < 2 ; i++) {
 			if (fusion->ld_map[i])
 				dma_free_coherent(&instance->pdev->dev,
diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c b/drivers/scsi/megaraid/megaraid_sas_fp.c
index 4463a538102a..b8b388a4e28f 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fp.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fp.c
@@ -326,9 +326,9 @@ u8 MR_ValidateMapInfo(struct megasas_instance *instance, u64 map_id)
 	else if (instance->supportmax256vd)
 		expected_size = sizeof(struct MR_FW_RAID_MAP_EXT);
 	else
-		expected_size = struct_size((struct MR_FW_RAID_MAP *)0,
-					    ldSpanMap,
-					    le16_to_cpu(pDrvRaidMap->ldCount));
+		expected_size = struct_size_t(struct MR_FW_RAID_MAP,
+					      ldSpanMap,
+					      le16_to_cpu(pDrvRaidMap->ldCount));
 
 	if (le32_to_cpu(pDrvRaidMap->totalSize) != expected_size) {
 		dev_dbg(&instance->pdev->dev, "megasas: map info structure size 0x%x",