On 2018/10/19 16:42, Boris Brezillon wrote:
On Fri, 19 Oct 2018 16:29:40 +0800
Liang Yang <liang.yang@xxxxxxxxxxx> wrote:
On 2018/10/19 4:50, Boris Brezillon wrote:
On Thu, 18 Oct 2018 13:09:05 +0800
Jianxin Pan <jianxin.pan@xxxxxxxxxxx> wrote:
+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.
+ 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.
You're right, I missed the call to meson_nfc_free_buffer() when
max_page_bytes < page_bytes. Still, this part is racy, just like the
nfc->data_buf replacement is if you have several NAND chips. I'd
recommend moving those bufs to the priv chip struct.
ok. i will move data_duf and info_buf to priv chip struct.
+
+ return 0;
+}
.
.
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
