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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>
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1 changed files with 28 additions and 18 deletions
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@ -65,11 +65,17 @@ struct kvm_resize_hpt {
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u32 order;
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u32 order;
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/* These fields protected by kvm->lock */
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/* These fields protected by kvm->lock */
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int error;
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bool prepare_done;
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/* Private to the work thread, until prepare_done is true,
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/* Possible values and their usage:
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* then protected by kvm->resize_hpt_sem */
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* <0 an error occurred during allocation,
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* -EBUSY allocation is in the progress,
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* 0 allocation made successfuly.
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*/
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int error;
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/* Private to the work thread, until error != -EBUSY,
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* then protected by kvm->lock.
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*/
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struct kvm_hpt_info hpt;
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struct kvm_hpt_info hpt;
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};
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};
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@ -1433,15 +1439,23 @@ static void resize_hpt_prepare_work(struct work_struct *work)
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struct kvm *kvm = resize->kvm;
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struct kvm *kvm = resize->kvm;
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int err;
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int err;
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if (WARN_ON(resize->error != -EBUSY))
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return;
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resize_hpt_debug(resize, "resize_hpt_prepare_work(): order = %d\n",
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resize_hpt_debug(resize, "resize_hpt_prepare_work(): order = %d\n",
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resize->order);
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resize->order);
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err = resize_hpt_allocate(resize);
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err = resize_hpt_allocate(resize);
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/* We have strict assumption about -EBUSY
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* when preparing for HPT resize.
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*/
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if (WARN_ON(err == -EBUSY))
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err = -EINPROGRESS;
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mutex_lock(&kvm->lock);
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mutex_lock(&kvm->lock);
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resize->error = err;
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resize->error = err;
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resize->prepare_done = true;
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mutex_unlock(&kvm->lock);
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mutex_unlock(&kvm->lock);
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}
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}
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@ -1466,14 +1480,12 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm,
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if (resize) {
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if (resize) {
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if (resize->order == shift) {
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if (resize->order == shift) {
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/* Suitable resize in progress */
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/* Suitable resize in progress? */
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if (resize->prepare_done) {
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ret = resize->error;
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ret = resize->error;
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if (ret == -EBUSY)
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if (ret != 0)
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resize_hpt_release(kvm, resize);
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} else {
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ret = 100; /* estimated time in ms */
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ret = 100; /* estimated time in ms */
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}
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else if (ret)
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resize_hpt_release(kvm, resize);
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goto out;
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goto out;
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}
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}
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@ -1493,6 +1505,8 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm,
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ret = -ENOMEM;
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ret = -ENOMEM;
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goto out;
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goto out;
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}
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}
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resize->error = -EBUSY;
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resize->order = shift;
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resize->order = shift;
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resize->kvm = kvm;
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resize->kvm = kvm;
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INIT_WORK(&resize->work, resize_hpt_prepare_work);
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INIT_WORK(&resize->work, resize_hpt_prepare_work);
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@ -1547,16 +1561,12 @@ long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm,
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if (!resize || (resize->order != shift))
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if (!resize || (resize->order != shift))
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goto out;
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goto out;
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ret = -EBUSY;
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if (!resize->prepare_done)
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goto out;
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ret = resize->error;
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ret = resize->error;
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if (ret != 0)
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if (ret)
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goto out;
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goto out;
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ret = resize_hpt_rehash(resize);
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ret = resize_hpt_rehash(resize);
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if (ret != 0)
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if (ret)
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goto out;
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goto out;
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resize_hpt_pivot(resize);
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resize_hpt_pivot(resize);
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