Messages in this thread | | | From | Konstantin Shkolnyy <> | Subject | RE: [PATCH v3 1/4 RESEND] USB: serial: cp210x: New register access functions. | Date | Mon, 18 Jan 2016 19:59:48 +0000 |
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> -----Original Message----- > From: linux-usb-owner@vger.kernel.org [mailto:linux-usb- > owner@vger.kernel.org] On Behalf Of Johan Hovold > Sent: Monday, January 18, 2016 11:33 > To: Konstantin Shkolnyy > Cc: johan@kernel.org; linux-usb@vger.kernel.org; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v3 1/4 RESEND] USB: serial: cp210x: New register access > functions. > > On Sat, Jan 16, 2016 at 01:46:24PM -0600, Konstantin Shkolnyy wrote: > > cp210x_get_config and cp210x_set_config are cumbersome to use. This > change > > introduces new register access functions to replace them. New functions > > are not yet called - the switch is done gradually in following changes. > > > > Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@gmail.com> > > --- > > change in v3: Presented new function addition as a separate patch #1, > > to simplify code review. > > Thanks for the v3. > > You should not be adding (static) functions before they have a caller as > this generates compiler warnings. > > Please define the new helper functions when converting their call > sites. You can split the 8, 16 and 32-bit helpers in separate patches and > possibly also separate read and write if that makes sense in order to > keep the diffs smaller.
I did split 8, 16 and 32 into 3 patches in v2, then it seemed to me it would be easier to review if I also separated new functions. I can just use an amended v2 as v4.
I add reads and writes together to avoid type mismatches in the code that reads/writes the same variable,
> > drivers/usb/serial/cp210x.c | 166 > ++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 166 insertions(+) > > > > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c > > index fd67958..324eb7e 100644 > > --- a/drivers/usb/serial/cp210x.c > > +++ b/drivers/usb/serial/cp210x.c > > @@ -323,6 +323,172 @@ struct cp210x_comm_status { > > #define PURGE_ALL 0x000f > > > > /* > > + * Reads a variable-sized block of CP210X_ registers, identified by req. > > + * Returns data into buf in native USB byte order. > > + */ > > +static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req, > > + void *buf, int bufsize) > > +{ > > + struct usb_serial *serial = port->serial; > > + struct cp210x_port_private *port_priv = > usb_get_serial_port_data(port); > > + void *dmabuf; > > + int result; > > + > > + dmabuf = kmalloc(bufsize, GFP_KERNEL); > > + if (!dmabuf) { > > + /* > > + * FIXME Some callers don't bother to check for error, > > + * at least give them consistent junk until they are fixed > > + */ > > + memset(buf, 0, bufsize); > > Instead of adding these FIXMEs and possibly risk introducing regressions > (these functions used to leave the previous values unchanged on errors),
The current cp210x_get_config() does clear the caller's storage on an error. So my refactoring just preserves the old behavior.
> how about adding the missing error handling first?
It's easier to work with and see bugs in cleaned up code, that's why I do it in this order. I do intend to fix the error handling later.
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