treewide: Use struct_size() for devm_kmalloc() and friends

Replaces open-coded struct size calculations with struct_size() for
devm_*, f2fs_*, and sock_* allocations. Automatically generated (and
manually adjusted) from the following Coccinelle script:

// Direct reference to struct field.
@@
identifier alloc =~ "devm_kmalloc|devm_kzalloc|sock_kmalloc|f2fs_kmalloc|f2fs_kzalloc";
expression HANDLE;
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@

- alloc(HANDLE, sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP)
+ alloc(HANDLE, struct_size(VAR, ELEMENT, COUNT), GFP)

// mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL);
@@
identifier alloc =~ "devm_kmalloc|devm_kzalloc|sock_kmalloc|f2fs_kmalloc|f2fs_kzalloc";
expression HANDLE;
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@

- alloc(HANDLE, sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP)
+ alloc(HANDLE, struct_size(VAR, ELEMENT, COUNT), GFP)

// Same pattern, but can't trivially locate the trailing element name,
// or variable name.
@@
identifier alloc =~ "devm_kmalloc|devm_kzalloc|sock_kmalloc|f2fs_kmalloc|f2fs_kzalloc";
expression HANDLE;
expression GFP;
expression SOMETHING, COUNT, ELEMENT;
@@

- alloc(HANDLE, sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP)
+ alloc(HANDLE, CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP)

Signed-off-by: Kees Cook <[email protected]>

drivers/dma/bcm-sba-raid.c

@@ -1499,9 +1499,8 @@ static int sba_prealloc_channel_resources(struct sba_device *sba)
 
 	for (i = 0; i < sba->max_req; i++) {
 		req = devm_kzalloc(sba->dev,
-				sizeof(*req) +
-				sba->max_cmd_per_req * sizeof(req->cmds[0]),
-				GFP_KERNEL);
+				   struct_size(req, cmds, sba->max_cmd_per_req),
+				   GFP_KERNEL);
 		if (!req) {
 			ret = -ENOMEM;
 			goto fail_free_cmds_pool;

drivers/dma/nbpfaxi.c

@@ -1305,8 +1305,8 @@ static int nbpf_probe(struct platform_device *pdev)
 	cfg = of_device_get_match_data(dev);
 	num_channels = cfg->num_channels;
 
-	nbpf = devm_kzalloc(dev, sizeof(*nbpf) + num_channels *
-			    sizeof(nbpf->chan[0]), GFP_KERNEL);
+	nbpf = devm_kzalloc(dev, struct_size(nbpf, chan, num_channels),
+			    GFP_KERNEL);
 	if (!nbpf)
 		return -ENOMEM;
 

drivers/dma/sprd-dma.c

@@ -805,8 +805,8 @@ static int sprd_dma_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	sdev = devm_kzalloc(&pdev->dev, sizeof(*sdev) +
-			    sizeof(*dma_chn) * chn_count,
+	sdev = devm_kzalloc(&pdev->dev,
+			    struct_size(sdev, channels, chn_count),
 			    GFP_KERNEL);
 	if (!sdev)
 		return -ENOMEM;