Re: [RFC v4+ hot_track 12/19] vfs: add one ioctl interface
On Mon, Oct 29, 2012 at 12:30:54PM +0800, zwu.ker...@gmail.com wrote:
+static int ioctl_heat_info(struct file *file, void __user *argp)
+{
+ struct inode *inode = file-f_dentry-d_inode;
+ struct hot_heat_info *heat_info;
+ struct hot_inode_item *he;
+ int ret = 0;
+
+ heat_info = kmalloc(sizeof(struct hot_heat_info),
+ GFP_KERNEL | GFP_NOFS);
heat_info is small enough to fit onto the stack, so you can avoid the
kmalloc, I don't think there are deep callstacks to be expected.
Nevertheless, if you want to use kmalloc here, then please check the
return value and use GFP_KERNEL.
+
+ if (copy_from_user((void *) heat_info,
+ argp,
+ sizeof(struct hot_heat_info)) != 0) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ he = hot_inode_item_find(inode-i_sb-s_hot_root, inode-i_ino);
+ if (!he) {
+ /* we don't have any info on this file yet */
+ ret = -ENODATA;
+ goto err;
+ }
+
+ spin_lock(he-hot_inode.lock);
+ heat_info-avg_delta_reads =
+ (__u64) he-hot_inode.hot_freq_data.avg_delta_reads;
+ heat_info-avg_delta_writes =
+ (__u64) he-hot_inode.hot_freq_data.avg_delta_writes;
+ heat_info-last_read_time =
+ (__u64) timespec_to_ns(he-hot_inode.hot_freq_data.last_read_time);
+ heat_info-last_write_time =
+ (__u64) timespec_to_ns(he-hot_inode.hot_freq_data.last_write_time);
+ heat_info-num_reads =
+ (__u32) he-hot_inode.hot_freq_data.nr_reads;
+ heat_info-num_writes =
+ (__u32) he-hot_inode.hot_freq_data.nr_writes;
+
+ if (heat_info-live 0) {
+ /*
+ * got a request for live temperature,
+ * call hot_hash_calc_temperature to recalculate
+ */
+ heat_info-temp =
+ inode-i_sb-s_hot_root-hot_func_type-ops.hot_temp_calc_fn(
+ he-hot_inode.hot_freq_data);
+ } else {
+ /* not live temperature, get it from the hashlist */
+ heat_info-temp = he-hot_inode.hot_freq_data.last_temp;
+ }
+ spin_unlock(he-hot_inode.lock);
+
+ hot_inode_item_put(he);
+
+ if (copy_to_user(argp, (void *) heat_info,
+ sizeof(struct hot_heat_info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+err:
+ kfree(heat_info);
+ return ret;
+}
david
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Re: [RFC v4+ hot_track 12/19] vfs: add one ioctl interface
On Wed, Nov 7, 2012 at 7:30 AM, David Sterba d...@jikos.cz wrote:
On Mon, Oct 29, 2012 at 12:30:54PM +0800, zwu.ker...@gmail.com wrote:
+static int ioctl_heat_info(struct file *file, void __user *argp)
+{
+ struct inode *inode = file-f_dentry-d_inode;
+ struct hot_heat_info *heat_info;
+ struct hot_inode_item *he;
+ int ret = 0;
+
+ heat_info = kmalloc(sizeof(struct hot_heat_info),
+ GFP_KERNEL | GFP_NOFS);
heat_info is small enough to fit onto the stack, so you can avoid the
kmalloc, I don't think there are deep callstacks to be expected.
ok, done.
Nevertheless, if you want to use kmalloc here, then please check the
return value and use GFP_KERNEL.
thanks for your pointing out.
+
+ if (copy_from_user((void *) heat_info,
+ argp,
+ sizeof(struct hot_heat_info)) != 0) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ he = hot_inode_item_find(inode-i_sb-s_hot_root, inode-i_ino);
+ if (!he) {
+ /* we don't have any info on this file yet */
+ ret = -ENODATA;
+ goto err;
+ }
+
+ spin_lock(he-hot_inode.lock);
+ heat_info-avg_delta_reads =
+ (__u64) he-hot_inode.hot_freq_data.avg_delta_reads;
+ heat_info-avg_delta_writes =
+ (__u64) he-hot_inode.hot_freq_data.avg_delta_writes;
+ heat_info-last_read_time =
+ (__u64) timespec_to_ns(he-hot_inode.hot_freq_data.last_read_time);
+ heat_info-last_write_time =
+ (__u64) timespec_to_ns(he-hot_inode.hot_freq_data.last_write_time);
+ heat_info-num_reads =
+ (__u32) he-hot_inode.hot_freq_data.nr_reads;
+ heat_info-num_writes =
+ (__u32) he-hot_inode.hot_freq_data.nr_writes;
+
+ if (heat_info-live 0) {
+ /*
+ * got a request for live temperature,
+ * call hot_hash_calc_temperature to recalculate
+ */
+ heat_info-temp =
+ inode-i_sb-s_hot_root-hot_func_type-ops.hot_temp_calc_fn(
+ he-hot_inode.hot_freq_data);
+ } else {
+ /* not live temperature, get it from the hashlist */
+ heat_info-temp = he-hot_inode.hot_freq_data.last_temp;
+ }
+ spin_unlock(he-hot_inode.lock);
+
+ hot_inode_item_put(he);
+
+ if (copy_to_user(argp, (void *) heat_info,
+ sizeof(struct hot_heat_info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+err:
+ kfree(heat_info);
+ return ret;
+}
david
--
Regards,
Zhi Yong Wu
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