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author | Serhii Popovych <spopovyc@redhat.com> | 2017-12-04 09:36:41 -0500 |
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committer | Paul Mackerras <paulus@ozlabs.org> | 2017-12-06 13:35:21 +1100 |
commit | 3073774e638ef18d222465fe92bfc8fccb90d288 (patch) | |
tree | 9743ab541a7aac8b4a59b1d8dfe39cd36b1f4405 /arch/powerpc/kvm/book3s_64_mmu_hv.c | |
parent | a63dd7480d8f3c2b52e1e2bcab83e3e64c7c61a1 (diff) | |
download | op-kernel-dev-3073774e638ef18d222465fe92bfc8fccb90d288.zip op-kernel-dev-3073774e638ef18d222465fe92bfc8fccb90d288.tar.gz |
KVM: PPC: Book3S HV: Drop prepare_done from struct kvm_resize_hpt
Currently the kvm_resize_hpt structure has two fields relevant to the
state of an ongoing resize: 'prepare_done', which indicates whether
the worker thread has completed or not, and 'error' which indicates
whether it was successful or not.
Since the success/failure isn't known until completion, this is
confusingly redundant. This patch consolidates the information into
just the 'error' value: -EBUSY indicates the worked is still in
progress, other negative values indicate (completed) failure, 0
indicates successful completion.
As a bonus this reduces size of struct kvm_resize_hpt by
__alignof__(struct kvm_hpt_info) and saves few bytes of code.
While there correct comment in struct kvm_resize_hpt which references
a non-existent semaphore (leftover from an early draft).
Assert with WARN_ON() in case of HPT allocation thread work runs more
than once for resize request or resize_hpt_allocate() returns -EBUSY
that is treated specially.
Change comparison against zero to make checkpatch.pl happy.
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Serhii Popovych <spopovyc@redhat.com>
[dwg: Changed BUG_ON()s to WARN_ON()s and altered commit message for
clarity]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c')
-rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_hv.c | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 9660972..f5f2c6b 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -65,11 +65,17 @@ struct kvm_resize_hpt { u32 order; /* These fields protected by kvm->lock */ + + /* Possible values and their usage: + * <0 an error occurred during allocation, + * -EBUSY allocation is in the progress, + * 0 allocation made successfuly. + */ int error; - bool prepare_done; - /* Private to the work thread, until prepare_done is true, - * then protected by kvm->resize_hpt_sem */ + /* Private to the work thread, until error != -EBUSY, + * then protected by kvm->lock. + */ struct kvm_hpt_info hpt; }; @@ -1433,15 +1439,23 @@ static void resize_hpt_prepare_work(struct work_struct *work) struct kvm *kvm = resize->kvm; int err; + if (WARN_ON(resize->error != -EBUSY)) + return; + resize_hpt_debug(resize, "resize_hpt_prepare_work(): order = %d\n", resize->order); err = resize_hpt_allocate(resize); + /* We have strict assumption about -EBUSY + * when preparing for HPT resize. + */ + if (WARN_ON(err == -EBUSY)) + err = -EINPROGRESS; + mutex_lock(&kvm->lock); resize->error = err; - resize->prepare_done = true; mutex_unlock(&kvm->lock); } @@ -1466,14 +1480,12 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm, if (resize) { if (resize->order == shift) { - /* Suitable resize in progress */ - if (resize->prepare_done) { - ret = resize->error; - if (ret != 0) - resize_hpt_release(kvm, resize); - } else { + /* Suitable resize in progress? */ + ret = resize->error; + if (ret == -EBUSY) ret = 100; /* estimated time in ms */ - } + else if (ret) + resize_hpt_release(kvm, resize); goto out; } @@ -1493,6 +1505,8 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm, ret = -ENOMEM; goto out; } + + resize->error = -EBUSY; resize->order = shift; resize->kvm = kvm; INIT_WORK(&resize->work, resize_hpt_prepare_work); @@ -1547,16 +1561,12 @@ long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm, if (!resize || (resize->order != shift)) goto out; - ret = -EBUSY; - if (!resize->prepare_done) - goto out; - ret = resize->error; - if (ret != 0) + if (ret) goto out; ret = resize_hpt_rehash(resize); - if (ret != 0) + if (ret) goto out; resize_hpt_pivot(resize); |