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media: b2c2: flexcop-usb: fix flexcop_usb_memory_req

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smatch generated this warning:

drivers/media/usb/b2c2/flexcop-usb.c:199 flexcop_usb_memory_req() warn: iterator 'i' not incremented

and indeed the function is not using i or updating buf.

The reason this always worked is that this function is called to write just
6 bytes (a MAC address) to the USB device, and so in practice there is only
a single chunk written. If we ever would need to write more than one chunk,
this function would fail since each chunk would read from or write to the
same buf address.

Rewrite the function to properly handle this.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
This commit is contained in:
Hans Verkuil
2024-06-20 09:52:26 +02:00
parent e1bda64a58
commit b178aa6f33
1 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/media/usb/b2c2/flexcop-usb.c
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@@ -179,7 +179,7 @@ static int flexcop_usb_memory_req(struct flexcop_usb *fc_usb,
flexcop_usb_request_t req, flexcop_usb_mem_page_t page_start,
u32 addr, int extended, u8 *buf, u32 len)
{
int i, ret = 0;
int ret = 0;
u16 wMax;
u32 pagechunk = 0;
@@ -196,7 +196,7 @@ static int flexcop_usb_memory_req(struct flexcop_usb *fc_usb,
default:
return -EINVAL;
}
for (i = 0; i < len;) {
while (len) {
pagechunk = min(wMax, bytes_left_to_read_on_page(addr, len));
deb_info("%x\n",
(addr & V8_MEMORY_PAGE_MASK) |
@@ -206,11 +206,12 @@ static int flexcop_usb_memory_req(struct flexcop_usb *fc_usb,
page_start + (addr / V8_MEMORY_PAGE_SIZE),
(addr & V8_MEMORY_PAGE_MASK) |
(V8_MEMORY_EXTENDED*extended),
&buf[i], pagechunk);
buf, pagechunk);
if (ret < 0)
return ret;
addr += pagechunk;
buf += pagechunk;
len -= pagechunk;
}
return 0;