Re: [PATCH 18/45] fs/quota: add kernel_quotactl() helper; remove in-kernel call to syscall

From: Jan Kara
Date: Mon Mar 26 2018 - 08:26:58 EST


On Thu 22-03-18 10:00:32, Dominik Brodowski wrote:
> Using the fs-internal kernel_quotactl() helper allows us to get rid of
> the fs-internal call to the sys_quotactl() syscall.
>
> This patch is part of a series which tries to remove in-kernel calls to
> syscalls. On this basis, the syscall entry path can be streamlined.
>
> Cc: Jan Kara <jack@xxxxxxxx>
> Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>

Looks good. Feel free to add:

Acked-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/quota/compat.c | 8 ++++----
> fs/quota/quota.c | 10 ++++++++--
> include/linux/quotaops.h | 3 +++
> 3 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/fs/quota/compat.c b/fs/quota/compat.c
> index 779caed4f078..1577a2fd51f4 100644
> --- a/fs/quota/compat.c
> +++ b/fs/quota/compat.c
> @@ -59,7 +59,7 @@ asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
> case Q_GETQUOTA:
> dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
> compat_dqblk = addr;
> - ret = sys_quotactl(cmd, special, id, dqblk);
> + ret = kernel_quotactl(cmd, special, id, dqblk);
> if (ret)
> break;
> if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
> @@ -75,12 +75,12 @@ asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
> get_user(data, &compat_dqblk->dqb_valid) ||
> put_user(data, &dqblk->dqb_valid))
> break;
> - ret = sys_quotactl(cmd, special, id, dqblk);
> + ret = kernel_quotactl(cmd, special, id, dqblk);
> break;
> case Q_XGETQSTAT:
> fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
> compat_fsqstat = addr;
> - ret = sys_quotactl(cmd, special, id, fsqstat);
> + ret = kernel_quotactl(cmd, special, id, fsqstat);
> if (ret)
> break;
> ret = -EFAULT;
> @@ -113,7 +113,7 @@ asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
> ret = 0;
> break;
> default:
> - ret = sys_quotactl(cmd, special, id, addr);
> + ret = kernel_quotactl(cmd, special, id, addr);
> }
> return ret;
> }
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index 43612e2a73af..860bfbe7a07a 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -833,8 +833,8 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
> * calls. Maybe we need to add the process quotas etc. in the future,
> * but we probably should use rlimits for that.
> */
> -SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
> - qid_t, id, void __user *, addr)
> +int kernel_quotactl(unsigned int cmd, const char __user *special,
> + qid_t id, void __user *addr)
> {
> uint cmds, type;
> struct super_block *sb = NULL;
> @@ -885,3 +885,9 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
> path_put(pathp);
> return ret;
> }
> +
> +SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
> + qid_t, id, void __user *, addr)
> +{
> + return kernel_quotactl(cmd, special, id, addr);
> +}
> diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
> index 2fb6fb11132e..ff63eac16a79 100644
> --- a/include/linux/quotaops.h
> +++ b/include/linux/quotaops.h
> @@ -105,6 +105,9 @@ int dquot_set_dqblk(struct super_block *sb, struct kqid id,
> int __dquot_transfer(struct inode *inode, struct dquot **transfer_to);
> int dquot_transfer(struct inode *inode, struct iattr *iattr);
>
> +int kernel_quotactl(unsigned int cmd, const char __user *special,
> + qid_t id, void __user *addr);
> +
> static inline struct mem_dqinfo *sb_dqinfo(struct super_block *sb, int type)
> {
> return sb_dqopt(sb)->info + type;
> --
> 2.16.2
>
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR