[PATCH] usb: LLVMLinux: Remove VLAIS from USB gadget

[charlebm]

From: Mark Charlebois <charlebm@xxxxxxxxx>


The use of variable length arrays in structs (VLAIS) in the Linux Kernel code
precludes the use of compilers which don't implement VLAIS (for instance the
Clang compiler). This patch removes the use of VLAIS in the gadget driver.

This version has been tested to compile cleanly. 

Signed-off-by: Mark Charlebois <charlebm@xxxxxxxxx>
Signed-off-by: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>
---
 drivers/usb/gadget/f_fs.c | 128 +++++++++++++++++++++++++++-------------------
 1 file changed, 76 insertions(+), 52 deletions(-)

--- linux.orig/drivers/usb/gadget/f_fs.c
+++ linux/drivers/usb/gadget/f_fs.c
@@ -30,7 +30,6 @@
 
 #define FUNCTIONFS_MAGIC	0xa647361 /* Chosen by a honest dice roll ;) */
 
-
 /* Debugging ****************************************************************/
 
 #ifdef VERBOSE_DEBUG
@@ -214,6 +213,8 @@
 	/* ids in stringtabs are set in functionfs_bind() */
 	const void			*raw_strings;
 	struct usb_gadget_strings	**stringtabs;
+	struct usb_gadget_strings	*stringtab;
+	struct usb_string		*strings;
 
 	/*
 	 * File system's super block, write once when file system is
@@ -263,7 +264,10 @@
 
 	struct ffs_ep			*eps;
 	u8				eps_revmap[16];
+	struct usb_descriptor_header	**fs_descs;
+	struct usb_descriptor_header	**hs_descs;
 	short				*interfaces_nums;
+	char				*raw_descs;
 
 	struct usb_function		function;
 };
@@ -1345,6 +1349,8 @@
 	kfree(ffs->raw_descs);
 	kfree(ffs->raw_strings);
 	kfree(ffs->stringtabs);
+	kfree(ffs->stringtab);
+	kfree(ffs->strings);
 }
 
 static void ffs_data_reset(struct ffs_data *ffs)
@@ -1357,6 +1363,8 @@
 	ffs->raw_descs = NULL;
 	ffs->raw_strings = NULL;
 	ffs->stringtabs = NULL;
+	ffs->stringtab = NULL;
+	ffs->strings = NULL;
 
 	ffs->raw_descs_length = 0;
 	ffs->raw_fs_descs_length = 0;
@@ -1528,12 +1536,10 @@
 	ffs_data_put(func->ffs);
 
 	kfree(func->eps);
-	/*
-	 * eps and interfaces_nums are allocated in the same chunk so
-	 * only one free is required.  Descriptors are also allocated
-	 * in the same chunk.
-	 */
-
+	kfree(func->fs_descs);
+	kfree(func->hs_descs);
+	kfree(func->interfaces_nums);
+	kfree(func->raw_descs);
 	kfree(func);
 }
 
@@ -1877,8 +1883,9 @@
 				  char *const _data, size_t len)
 {
 	u32 str_count, needed_count, lang_count;
-	struct usb_gadget_strings **stringtabs, *t;
-	struct usb_string *strings, *s;
+	struct usb_gadget_strings *t, **stringtabs = NULL;
+	struct usb_gadget_strings *stringtab = NULL;
+	struct usb_string *s, *strings = NULL;
 	const char *data = _data;
 
 	ENTER();
@@ -1907,33 +1914,33 @@
 		return 0;
 	}
 
-	/* Allocate everything in one chunk so there's less maintenance. */
 	{
-		struct {
-			struct usb_gadget_strings *stringtabs[lang_count + 1];
-			struct usb_gadget_strings stringtab[lang_count];
-			struct usb_string strings[lang_count*(needed_count+1)];
-		} *d;
 		unsigned i = 0;
-
-		d = kmalloc(sizeof *d, GFP_KERNEL);
-		if (unlikely(!d)) {
+		struct usb_gadget_strings **b;
+
+		stringtabs = kmalloc(sizeof(*stringtabs)*(lang_count + 1),
+			GFP_KERNEL);
+		stringtab = kmalloc(sizeof(*stringtab)*(lang_count),
+			GFP_KERNEL);
+		strings = kmalloc(sizeof(*strings)
+			* (lang_count * (needed_count + 1)), GFP_KERNEL);
+		if (unlikely(!stringtabs || !stringtab || !strings)) {
+			kfree(stringtabs);
+			kfree(stringtab);
+			kfree(strings);
 			kfree(_data);
 			return -ENOMEM;
 		}
-
-		stringtabs = d->stringtabs;
-		t = d->stringtab;
+		b = stringtabs;
+		t = stringtab;
 		i = lang_count;
 		do {
-			*stringtabs++ = t++;
+			*b++ = t++;
 		} while (--i);
-		*stringtabs = NULL;
+		*b = NULL;
 
-		stringtabs = d->stringtabs;
-		t = d->stringtab;
-		s = d->strings;
-		strings = s;
+		t = stringtab;
+		s = strings;
 	}
 
 	/* For each language */
@@ -1991,12 +1998,16 @@
 
 	/* Done! */
 	ffs->stringtabs = stringtabs;
+	ffs->stringtab = stringtab;
+	ffs->strings = strings;
 	ffs->raw_strings = _data;
 
 	return 0;
 
 error_free:
 	kfree(stringtabs);
+	kfree(stringtab);
+	kfree(strings);
 error:
 	kfree(_data);
 	return -EINVAL;
@@ -2207,17 +2218,12 @@
 
 	int ret;
 
-	/* Make it a single chunk, less management later on */
-	struct {
-		struct ffs_ep eps[ffs->eps_count];
-		struct usb_descriptor_header
-			*fs_descs[full ? ffs->fs_descs_count + 1 : 0];
-		struct usb_descriptor_header
-			*hs_descs[high ? ffs->hs_descs_count + 1 : 0];
-		short inums[ffs->interfaces_count];
-		char raw_descs[high ? ffs->raw_descs_length
-				    : ffs->raw_fs_descs_length];
-	} *data;
+	struct ffs_ep *eps = NULL;
+	struct usb_descriptor_header **fs_descs = NULL;
+	struct usb_descriptor_header **hs_descs = NULL;
+	short *inums = NULL;
+	char *raw_descs = NULL;
+
 
 	ENTER();
 
@@ -2225,21 +2231,40 @@
 	if (unlikely(!(full | high)))
 		return -ENOTSUPP;
 
-	/* Allocate */
-	data = kmalloc(sizeof *data, GFP_KERNEL);
-	if (unlikely(!data))
+	size_t eps_sz = sizeof(*eps)*ffs->eps_count;
+	eps = kmalloc(eps_sz, GFP_KERNEL);
+	fs_descs = kmalloc(sizeof(*fs_descs)*
+			   (full ? ffs->fs_descs_count + 1 : 0), GFP_KERNEL);
+	hs_descs = kmalloc(sizeof(*hs_descs)*
+			   (high ? ffs->hs_descs_count + 1 : 0), GFP_KERNEL);
+	size_t inums_sz = sizeof(*inums)*ffs->interfaces_count;
+	inums = kmalloc(inums_sz, GFP_KERNEL);
+	size_t raw_descs_sz = sizeof(*raw_descs)*(high ? ffs->raw_descs_length :
+					ffs->raw_fs_descs_length);
+	raw_descs = kmalloc(raw_descs_sz, GFP_KERNEL);
+
+	if (unlikely(!eps || !fs_descs || !hs_descs || !inums || !raw_descs)) {
+		kfree(eps);
+		kfree(fs_descs);
+		kfree(hs_descs);
+		kfree(inums);
+		kfree(raw_descs);
 		return -ENOMEM;
+	}
 
 	/* Zero */
-	memset(data->eps, 0, sizeof data->eps);
-	memcpy(data->raw_descs, ffs->raw_descs + 16, sizeof data->raw_descs);
-	memset(data->inums, 0xff, sizeof data->inums);
+	memset(eps, 0, eps_sz);
+	memcpy(raw_descs, ffs->raw_descs + 16, raw_descs_sz);
+	memset(inums, 0xff, inums_sz);
 	for (ret = ffs->eps_count; ret; --ret)
-		data->eps[ret].num = -1;
+		eps[ret].num = -1;
 
 	/* Save pointers */
-	func->eps             = data->eps;
-	func->interfaces_nums = data->inums;
+	func->eps             = eps;
+	func->fs_descs        = fs_descs;
+	func->hs_descs        = hs_descs;
+	func->interfaces_nums = inums;
+	func->raw_descs       = raw_descs;
 
 	/*
 	 * Go through all the endpoint descriptors and allocate
@@ -2247,10 +2272,9 @@
 	 * numbers without worrying that it may be described later on.
 	 */
 	if (likely(full)) {
-		func->function.fs_descriptors = data->fs_descs;
+		func->function.fs_descriptors = fs_descs;
 		ret = ffs_do_descs(ffs->fs_descs_count,
-				   data->raw_descs,
-				   sizeof data->raw_descs,
+				   raw_descs, raw_descs_sz,
 				   __ffs_func_bind_do_descs, func);
 		if (unlikely(ret < 0))
 			goto error;
@@ -2259,10 +2283,9 @@
 	}
 
 	if (likely(high)) {
-		func->function.hs_descriptors = data->hs_descs;
+		func->function.hs_descriptors = hs_descs;
 		ret = ffs_do_descs(ffs->hs_descs_count,
-				   data->raw_descs + ret,
-				   (sizeof data->raw_descs) - ret,
+				   raw_descs + ret, raw_descs_sz - ret,
 				   __ffs_func_bind_do_descs, func);
 	}
 
@@ -2273,7 +2296,7 @@
 	 */
 	ret = ffs_do_descs(ffs->fs_descs_count +
 			   (high ? ffs->hs_descs_count : 0),
-			   data->raw_descs, sizeof data->raw_descs,
+			   raw_descs, raw_descs_sz,
 			   __ffs_func_bind_do_nums, func);
 	if (unlikely(ret < 0))
 		goto error;
--
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