Re: [PATCH v5 14/19] KVM: Clean up local variable usage in __kvm_set_memory_region()
From: Peter Xu <peterx@redhat.com>
Date: 2020-02-06 19:36:52
Also in:
kvm, kvmarm, linux-mips, lkml
On Thu, Feb 06, 2020 at 11:22:30AM -0800, Sean Christopherson wrote:
On Thu, Feb 06, 2020 at 02:06:41PM -0500, Peter Xu wrote:quoted
On Tue, Jan 21, 2020 at 02:31:52PM -0800, Sean Christopherson wrote: [...]quoted
@@ -1101,52 +1099,55 @@ int __kvm_set_memory_region(struct kvm *kvm, if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) return -EINVAL; - slot = id_to_memslot(__kvm_memslots(kvm, as_id), id); - base_gfn = mem->guest_phys_addr >> PAGE_SHIFT; - npages = mem->memory_size >> PAGE_SHIFT; - - if (npages > KVM_MEM_MAX_NR_PAGES) - return -EINVAL; - /* * Make a full copy of the old memslot, the pointer will become stale * when the memslots are re-sorted by update_memslots(). */ - old = *slot; + tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); + old = *tmp; + tmp = NULL;Shall we keep this chunk to the patch where it will be used? Other than that, it looks good to me.I assume you're talking about doing this instead of using @tmp? old = *id_to_memslot(__kvm_memslots(kvm, as_id), id);
Yes.
quoted hunk ↗ jump to hunk
It's obviously possible, but I really like resulting diff for __kvm_set_memory_region() in "KVM: Terminate memslot walks via used_slots" when tmp is used.@@ -1104,8 +1203,13 @@ int __kvm_set_memory_region(struct kvm *kvm, * when the memslots are re-sorted by update_memslots(). */ tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); - old = *tmp; - tmp = NULL; + if (tmp) { + old = *tmp; + tmp = NULL; + } else { + memset(&old, 0, sizeof(old)); + old.id = id; + }
I normally don't do that, for each patch I'll try to make it consistent to itself, assuming that follow-up patches can be rejected. I don't have strong opinion either, please feel free to keep them if no one disagrees. -- Peter Xu _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel