On 10.12.19 18:07, Milan Pandurov wrote:
By storing kvm_stat_kind inside kvm_stat_data struct we can remove
duplicated code and remove usage of temporary kvm_stat_data struct
inside vm_stat_get et al.
Signed-off-by: Milan Pandurov <milanpa@xxxxxxxxx>
---
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 118 +++++++++++++++++----------------------
2 files changed, 53 insertions(+), 66 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7ed1e2f8641e..212d5117efda 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1112,6 +1112,7 @@ struct kvm_stat_data {
int offset;
int mode;
struct kvm *kvm;
+ enum kvm_stat_kind kind;
Why don't we just add a pointer to the debugfs_item here? That would
make offset, mode and kind redundant. They are pretty much just copies
from the template and immutable afterwards, no?
};
struct kvm_stats_debugfs_item {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 00268290dcbd..155f144fcc7c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -113,7 +113,7 @@ struct dentry *kvm_debugfs_dir;
EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
static int kvm_debugfs_num_entries;
-static const struct file_operations *stat_fops_per_vm[];
+static const struct file_operations stat_fops_per_vm;
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
@@ -652,9 +652,10 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
stat_data->kvm = kvm;
stat_data->offset = p->offset;
stat_data->mode = p->mode ? p->mode : 0644;
+ stat_data->kind = p->kind;
kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
debugfs_create_file(p->name, stat_data->mode, kvm->debugfs_dentry,
- stat_data, stat_fops_per_vm[p->kind]);
+ stat_data, &stat_fops_per_vm);
}
return 0;
}
@@ -4033,105 +4034,96 @@ static int kvm_debugfs_release(struct inode *inode, struct file *file)
return 0;
}
-static int vm_stat_get_per_vm(void *data, u64 *val)
+static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
{
- struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
-
- *val = *(ulong *)((void *)stat_data->kvm + stat_data->offset);
+ *val = *(ulong *)((void *)kvm + offset);
return 0;
}
-static int vm_stat_clear_per_vm(void *data, u64 val)
+static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
{
- struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
-
- if (val)
- return -EINVAL;
-
- *(ulong *)((void *)stat_data->kvm + stat_data->offset) = 0;
+ *(ulong *)((void *)kvm + offset) = 0;
return 0;
}
-static int vm_stat_get_per_vm_open(struct inode *inode, struct file *file)
-{
- __simple_attr_check_format("%llu\n", 0ull);
- return kvm_debugfs_open(inode, file, vm_stat_get_per_vm,
- vm_stat_clear_per_vm, "%llu\n");
-}
-
-static const struct file_operations vm_stat_get_per_vm_fops = {
- .owner = THIS_MODULE,
- .open = vm_stat_get_per_vm_open,
- .release = kvm_debugfs_release,
- .read = simple_attr_read,
- .write = simple_attr_write,
- .llseek = no_llseek,
-};
-
-static int vcpu_stat_get_per_vm(void *data, u64 *val)
+static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
{
int i;
- struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
struct kvm_vcpu *vcpu;
*val = 0;
- kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
- *val += *(u64 *)((void *)vcpu + stat_data->offset);
+ kvm_for_each_vcpu(i, vcpu, kvm)
+ *val += *(u64 *)((void *)vcpu + offset);
return 0;
}
-static int vcpu_stat_clear_per_vm(void *data, u64 val)
+static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
{
int i;
- struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
struct kvm_vcpu *vcpu;
- if (val)
- return -EINVAL;
-
- kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
- *(u64 *)((void *)vcpu + stat_data->offset) = 0;
+ kvm_for_each_vcpu(i, vcpu, kvm)
+ *(u64 *)((void *)vcpu + offset) = 0;
return 0;
}
-static int vcpu_stat_get_per_vm_open(struct inode *inode, struct file *file)
+struct kvm_stat_operations {
+ int (*get)(struct kvm *kvm, size_t offset, u64 *val);
+ int (*clear)(struct kvm *kvm, size_t offset);
+};
+
+static const struct kvm_stat_operations kvm_stat_ops[] = {
+ [KVM_STAT_VM] = { .get = kvm_get_stat_per_vm,
+ .clear = kvm_clear_stat_per_vm },
+ [KVM_STAT_VCPU] = { .get = kvm_get_stat_per_vcpu,
+ .clear = kvm_clear_stat_per_vcpu },
+};
+
+static int kvm_stat_data_get(void *data, u64 *val)
+{
+ struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+ return kvm_stat_ops[stat_data->kind].get(stat_data->kvm,
+ stat_data->offset, val);
I'm fairly confident the compiler will produce much better code if you
make this an explicit if/else branch or switch statement rather than go
through the ops indirection.
+}
+
+static int kvm_stat_data_clear(void *data, u64 val)
+{
+ struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+ return kvm_stat_ops[stat_data->kind].clear(stat_data->kvm,
+ stat_data->offset);
This introduces a change in behavior. Before, on set of a value != 0 you
would get -EINVAL. Now, the value is just silently ignored. Please add
back the val != 0 check here.
Apart from the comments above, the patch looks like a simple, useful
cleanup to me.
Thanks a lot,
Alex
+}
+
+static int kvm_stat_data_open(struct inode *inode, struct file *file)
{
__simple_attr_check_format("%llu\n", 0ull);
- return kvm_debugfs_open(inode, file, vcpu_stat_get_per_vm,
- vcpu_stat_clear_per_vm, "%llu\n");
+ return kvm_debugfs_open(inode, file, kvm_stat_data_get,
+ kvm_stat_data_clear, "%llu\n");
}
-static const struct file_operations vcpu_stat_get_per_vm_fops = {
- .owner = THIS_MODULE,
- .open = vcpu_stat_get_per_vm_open,
+static const struct file_operations stat_fops_per_vm = {
+ .owner = THIS_MODULE,
+ .open = kvm_stat_data_open,
.release = kvm_debugfs_release,
- .read = simple_attr_read,
- .write = simple_attr_write,
- .llseek = no_llseek,
-};
-
-static const struct file_operations *stat_fops_per_vm[] = {
- [KVM_STAT_VCPU] = &vcpu_stat_get_per_vm_fops,
- [KVM_STAT_VM] = &vm_stat_get_per_vm_fops,
+ .read = simple_attr_read,
+ .write = simple_attr_write,
+ .llseek = no_llseek,
};
static int vm_stat_get(void *_offset, u64 *val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
- struct kvm_stat_data stat_tmp = {.offset = offset};
u64 tmp_val;
*val = 0;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
- stat_tmp.kvm = kvm;
- vm_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
+ vm_stat_get_per_vm(kvm, offset, &tmp_val);
*val += tmp_val;
}
mutex_unlock(&kvm_lock);
@@ -4142,15 +4134,13 @@ static int vm_stat_clear(void *_offset, u64 val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
- struct kvm_stat_data stat_tmp = {.offset = offset};
if (val)
return -EINVAL;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
- stat_tmp.kvm = kvm;
- vm_stat_clear_per_vm((void *)&stat_tmp, 0);
+ vm_stat_clear_per_vm(kvm, offset);
}
mutex_unlock(&kvm_lock);
@@ -4163,14 +4153,12 @@ static int vcpu_stat_get(void *_offset, u64 *val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
- struct kvm_stat_data stat_tmp = {.offset = offset};
u64 tmp_val;
*val = 0;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
- stat_tmp.kvm = kvm;
- vcpu_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
+ vcpu_stat_get_per_vm(kvm, offset, &tmp_val);
*val += tmp_val;
}
mutex_unlock(&kvm_lock);
@@ -4181,15 +4169,13 @@ static int vcpu_stat_clear(void *_offset, u64 val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
- struct kvm_stat_data stat_tmp = {.offset = offset};
if (val)
return -EINVAL;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
- stat_tmp.kvm = kvm;
- vcpu_stat_clear_per_vm((void *)&stat_tmp, 0);
+ kvm_clear_stat_per_vcpu(kvm, offset);
}
mutex_unlock(&kvm_lock);
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