Re: [PATCH] PC, KVM, CMA: Fix regression caused by wrong get_order() use
From: Aneesh Kumar K.V <hidden>
Date: 2014-08-13 11:56:34
Also in:
kvm, lkml, stable
Alexey Kardashevskiy [off-list ref] writes:
fc95ca7284bc54953165cba76c3228bd2cdb9591 claims that there is no functional change but this is not true as it calls get_order() (which takes bytes) where it should have called ilog2() and the kernel stops on VM_BUG_ON(). This replaces get_order() with ilog2().
Should we round it up ? ie, ilog2(kvm_rma_pages - 1) + 1 ?
Suggested-by: Paul Mackerras <redacted> Cc: Alexander Graf <redacted> Cc: Aneesh Kumar K.V <redacted> Cc: Joonsoo Kim <redacted> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: <redacted>
Why stable ? We merged it this merge window.
quoted hunk ↗ jump to hunk
Signed-off-by: Alexey Kardashevskiy <redacted> --- arch/powerpc/kvm/book3s_hv_builtin.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c index 329d7fd..bfe9f01 100644 --- a/arch/powerpc/kvm/book3s_hv_builtin.c +++ b/arch/powerpc/kvm/book3s_hv_builtin.c@@ -101,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma() ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL); if (!ri) return NULL; - page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages)); + page = cma_alloc(kvm_cma, kvm_rma_pages, ilog2(kvm_rma_pages)); if (!page) goto err_out; atomic_set(&ri->use_count, 1);@@ -135,12 +135,12 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages) { unsigned long align_pages = HPT_ALIGN_PAGES; - VM_BUG_ON(get_order(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); + VM_BUG_ON(ilog2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT); /* Old CPUs require HPT aligned on a multiple of its size */ if (!cpu_has_feature(CPU_FTR_ARCH_206)) align_pages = nr_pages; - return cma_alloc(kvm_cma, nr_pages, get_order(align_pages)); + return cma_alloc(kvm_cma, nr_pages, ilog2(align_pages)); } EXPORT_SYMBOL_GPL(kvm_alloc_hpt);-- 2.0.0