[PATCH v5 2/2] mtd: rawnand: meson: add support for Amlogic NAND flash controller

On 2018/10/19 4:50, Boris Brezillon wrote:

On Thu, 18 Oct 2018 13:09:05 +0800
Jianxin Pan [off-list ref] wrote:

quoted

+static int meson_nfc_buffer_init(struct mtd_info *mtd)
+{
+	struct nand_chip *nand = mtd_to_nand(mtd);
+	struct meson_nfc *nfc = nand_get_controller_data(nand);
+	static int max_page_bytes, max_info_bytes;
+	int page_bytes, info_bytes;
+	int nsectors;
+
+	nsectors = mtd->writesize / nand->ecc.size;
+	page_bytes =  mtd->writesize + mtd->oobsize;
+	info_bytes = nsectors * PER_INFO_BYTE;
+
+	if (nfc->data_buf && nfc->info_buf) {
+		if (max_page_bytes < page_bytes)
+			meson_nfc_free_buffer(nfc);
+		else
+			return 0;
+	}
+
+	max_page_bytes = max_t(int, max_page_bytes, page_bytes);
+	max_info_bytes = max_t(int, max_info_bytes, info_bytes);
+
+	nfc->data_buf = kmalloc(max_page_bytes, GFP_KERNEL);

Is there a good reason for not using chip->data_buf and allocating a
new buffer here?

when calling read_oob or write_oob, i need a mid-buffer which is used in 
meson_nfc_prase_data_oob(). i.e. after reading a page data into 
nfc->data_buf, I will format it and transfer to chip->data_buf.

quoted

+	if (!nfc->data_buf)
+		return -ENOMEM;
+
+	nfc->info_buf = kmalloc(max_info_bytes, GFP_KERNEL);
+	if (!nfc->info_buf) {
+		kfree(nfc->data_buf);
+		return -ENOMEM;
+	}

I'd recommend moving this info_buf in the priv chip struct, otherwise
you'll have to protect nfc->info_buf with a lock to prevent an already
register chip from using this pointer while you're reallocating the
buffer. Also, I think you have a memleak here.

ok, i will move it in the chip struct .

but how memleak happens even i have called meson_nfc_free_buffer before 
and free data_buf if info_buf alloc faied.

quoted

+
+	return 0;
+}

.