Re: [PATCH bpf v2] lib/buildid: use __kernel_read() for sleepable context

[Shakeel Butt]

On Thu, Dec 18, 2025 at 11:55:39PM +0000, Matthew Wilcox wrote:
> On Thu, Dec 18, 2025 at 12:55:05PM -0800, Shakeel Butt wrote:
> > +	do {
> > +		ret = __kernel_read(r->file, buf, sz, &pos);
> > +		if (ret <= 0) {
> > +			r->err = ret ?: -EIO;
> > +			return NULL;
> > +		}
> > +		buf += ret;
> > +		sz -= ret;
> > +	} while (sz > 0);
> 
> Why are you doing a loop around __kernel_read()?  eg kernel_read() does
> not do a read around __kernel_read().  The callers of kernel_read()
> don't do a loop either.  So what makes you think it needs to have a loop
> around it?

I am assuming that __kernel_read() can return less data than the
requested. Is that assumption incorrect?