On 28 Feb 2018, at 10:47 PM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
On Mon, Feb 26, 2018 at 11:04:57PM +0800, Kai-Heng Feng wrote:
+static char quirks_param[128];
+module_param_string(quirks, quirks_param, sizeof(quirks_param), 0644);
+MODULE_PARM_DESC(quirks, "Add/modify USB quirks by specifying
quirks=vendorID:productID:quirks");
+
+static char quirks_param_orig[128];
+static u32 usb_detect_dynamic_quirks(struct usb_device *udev)
+{
+ u16 vid = le16_to_cpu(udev->descriptor.idVendor);
+ u16 pid = le16_to_cpu(udev->descriptor.idProduct);
+ struct quirk_entry *quirk;
+
+ mutex_lock(&quirk_mutex);
+ if (strcmp(quirks_param, quirks_param_orig) != 0) {
+ strcpy(quirks_param_orig, quirks_param);
What happens if the user is writing to quirks_param at the same time
that you memcpy it?
I think you're going about this wrong by trying to use the
module_param_string machinery. You should be using module_param_cb()
to build the quirks list when the user writes it (and then translate
back into a string when the user wants to read from it.
Thanks! module_param_cb() is exactly what I want.
I’ll use it in next version.
Also, you won't need to use a linked list for this; you can just allocate
an array of quirks.
I use linked list because the total quirks number is known after the entire
string gets parsed.
Do you suggest that I should just alloc a predefined number (like 16) quirk
entries, instead of doing it dynamically?
Kai-Heng
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