On Fri, Apr 01, 2022, Dan Carpenter wrote:
> The alloc_workqueue() function does not return error pointers, it
> returns NULL on error. Update the check accordingly.
>
> Fixes: 1a3320dd2939 ("KVM: MMU: propagate alloc_workqueue failure")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Obviously, I noticed that the patch says "propagate alloc_workqueue
> failure" so that's a puzzling thing. Merge issue perhaps? In
> linux-next it alloc_workqueue() returns NULL.
No merge issue, just a goof. The "propagate" patch was added because KVM neglected
to check for allocation failure, so at least it was a step in the right direction :-)
> arch/x86/kvm/mmu/tdp_mmu.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index a2f9a34a0168..d71d177ae6b8 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -22,8 +22,8 @@ int kvm_mmu_init_tdp_mmu(struct kvm *kvm)
> return 0;
>
> wq = alloc_workqueue("kvm", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 0);
> - if (IS_ERR(wq))
> - return PTR_ERR(wq);
> + if (!wq)
> + return -ENOMEM;
>
> /* This should not be changed for the lifetime of the VM. */
> kvm->arch.tdp_mmu_enabled = true;
> --
Paolo, any objection to also returning '0' in all non-error paths? There's no
need to return whether or not the TDP MMU is enabled since that's handled locally,
and the "return 1" is rather odd.
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index dbf46dd98618..dec32b4a13aa 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5779,7 +5779,7 @@ int kvm_mmu_init_vm(struct kvm *kvm)
spin_lock_init(&kvm->arch.mmu_unsync_pages_lock);
r = kvm_mmu_init_tdp_mmu(kvm);
- if (r < 0)
+ if (r)
return r;
node->track_write = kvm_mmu_pte_write;
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index a2f9a34a0168..3a60b999e1aa 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -31,7 +31,7 @@ int kvm_mmu_init_tdp_mmu(struct kvm *kvm)
spin_lock_init(&kvm->arch.tdp_mmu_pages_lock);
INIT_LIST_HEAD(&kvm->arch.tdp_mmu_pages);
kvm->arch.tdp_mmu_zap_wq = wq;
- return 1;
+ return 0;
}
/* Arbitrarily returns true so that this may be used in if statements. */
