Messages in this thread | | | Subject | Re: [PATCH 1/2] KVM: s390: gaccess: Cleanup access to guest frames | From | David Hildenbrand <> | Date | Wed, 18 Aug 2021 10:44:34 +0200 |
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On 18.08.21 10:06, Janosch Frank wrote: > On 8/18/21 9:54 AM, David Hildenbrand wrote: >> On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >>> Introduce a helper function for guest frame access. >>> Rewrite the calculation of the gpa and the length of the segment >>> to be more readable. >>> >>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> > [...] >>> - unsigned long _len, gpa; >>> + unsigned long gpa; >>> + unsigned int seg; >>> int rc = 0; >>> >>> while (len && !rc) { >>> gpa = kvm_s390_real_to_abs(vcpu, gra); >>> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >>> - if (mode) >>> - rc = write_guest_abs(vcpu, gpa, data, _len); >>> - else >>> - rc = read_guest_abs(vcpu, gpa, data, _len); >>> - len -= _len; >>> - gra += _len; >>> - data += _len; >>> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); >> >> What does "seg" mean? I certainly know when "len" means -- which is also >> what the function eats. > > What does "_len" mean especially in contrast to "len"? > > "seg" is used in the common kvm guest access functions so it's at least > consistent although I share the sentiment that it's not a great name for > the length we access inside the page. > > Originally I suggested "len_in_page" if you have a better name I'd > expect we'll both be happy to discuss it :-)
Similar code I encountered in other places uses "len" vs "cur_len" or "total_len" vs. "cur_len". I agree that everything is better than "len" vs. "_len".
I just cannot come up with a proper word for "seg" that would make sense. "Segment" ? Maybe my uneducated mind is missing some important English words that just fit perfectly here.
Anyhow, just my 2 cents, you maintain this code :)
-- Thanks,
David / dhildenb
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