> -----Original Message----- > From: Greg KH <gre...@linuxfoundation.org> > Sent: Wednesday, March 10, 2021 3:13 AM > To: Chen, Mike Ximing <mike.ximing.c...@intel.com> > Cc: netdev@vger.kernel.org; da...@davemloft.net; k...@kernel.org; > a...@arndb.de; Williams, Dan J <dan.j.willi...@intel.com>; pierre- > louis.boss...@linux.intel.com; Gage Eads <gage.e...@intel.com> > Subject: Re: [PATCH v10 03/20] dlb: add resource and device initialization > > On Wed, Mar 10, 2021 at 01:33:24AM +0000, Chen, Mike Ximing wrote: > > > > > -----Original Message----- > > > From: Greg KH <gre...@linuxfoundation.org> > > > > > > On Wed, Feb 10, 2021 at 11:54:06AM -0600, Mike Ximing Chen wrote: > > > > + > > > > +#include "dlb_bitmap.h" > > > > + > > > > +#define BITS_SET(x, val, mask) (x = ((x) & ~(mask)) \ > > > > + | (((val) << (mask##_LOC)) & (mask))) > > > > +#define BITS_GET(x, mask) (((x) & (mask)) >> (mask##_LOC)) > > > > > > Why not use the built-in kernel functions for this? Why are you > > > creating your own? > > > > > FIELD_GET(_mask, _val) and FIELD_PREP(_mask, _val) in > > include/linux/bitfield.h > > are similar to our BITS_GET() and BITS_SET(). However in our case, > > mask##_LOC > > is a known constant defined in dlb_regs.h, so we don't need to use > > _buildin_ffs(mask) to calculate the location of mask as FIELD_GET() and > FIELD_PREP() > > do. We can still use FIELD_GET and FIELD_PREP, but our macros are a little > > more > > efficient. Would it be OK to keep them? > > No, please use the kernel-wide proper functions, there's no need for > single tiny driver to be "special" in this regard. If somehow the > in-kernel functions are not sufficient, it's always better to fix them > up than to go your own way here. >
OK. I will use FIELD_GET() and FIELD_PREP() macros in the next revision. Thanks Mike
