Re: [PATCH v8 1/6] Uprobes: Simplify uprobe_register() body

Song Liu
2018-08-11T08:00:49Z

On Wed, Aug 8, 2018 at 9:18 PM, Ravi Bangoria
<ravi.bangoria@linux.ibm.com> wrote:
> Simplify uprobe_register() function body and let __uprobe_register()
> handle everything. Also move dependency functions around to fix build
> failures.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>

Reviewed-by: Song Liu <songliubraving@fb.com>

> ---
> kernel/events/uprobes.c | 69 ++++++++++++++++++++++++++-----------------------
> 1 file changed, 36 insertions(+), 33 deletions(-)
>
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index ccc579a7d32e..471eac896635 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -840,13 +840,8 @@ register_for_each_vma(struct uprobe *uprobe, struct uprobe_consumer *new)
> return err;
> }
>
> -static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc)
> -{
> - consumer_add(uprobe, uc);
> - return register_for_each_vma(uprobe, uc);
> -}
> -
> -static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
> +static void
> +__uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
> {
> int err;
>
> @@ -860,24 +855,46 @@ static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *u
> }
>
> /*
> - * uprobe_register - register a probe
> + * uprobe_unregister - unregister a already registered probe.
> + * @inode: the file in which the probe has to be removed.
> + * @offset: offset from the start of the file.
> + * @uc: identify which probe if multiple probes are colocated.
> + */
> +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
> +{
> + struct uprobe *uprobe;
> +
> + uprobe = find_uprobe(inode, offset);
> + if (WARN_ON(!uprobe))
> + return;
> +
> + down_write(&uprobe->register_rwsem);
> + __uprobe_unregister(uprobe, uc);
> + up_write(&uprobe->register_rwsem);
> + put_uprobe(uprobe);
> +}
> +EXPORT_SYMBOL_GPL(uprobe_unregister);
> +
> +/*
> + * __uprobe_register - register a probe
> * @inode: the file in which the probe has to be placed.
> * @offset: offset from the start of the file.
> * @uc: information on howto handle the probe..
> *
> - * Apart from the access refcount, uprobe_register() takes a creation
> + * Apart from the access refcount, __uprobe_register() takes a creation
> * refcount (thro alloc_uprobe) if and only if this @uprobe is getting
> * inserted into the rbtree (i.e first consumer for a @inode:@offset
> * tuple). Creation refcount stops uprobe_unregister from freeing the
> * @uprobe even before the register operation is complete. Creation
> * refcount is released when the last @uc for the @uprobe
> - * unregisters. Caller of uprobe_register() is required to keep @inode
> + * unregisters. Caller of __uprobe_register() is required to keep @inode
> * (and the containing mount) referenced.
> *
> * Return errno if it cannot successully install probes
> * else return 0 (success)
> */
> -int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
> +static int __uprobe_register(struct inode *inode, loff_t offset,
> + struct uprobe_consumer *uc)
> {
> struct uprobe *uprobe;
> int ret;
> @@ -904,7 +921,8 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *
> down_write(&uprobe->register_rwsem);
> ret = -EAGAIN;
> if (likely(uprobe_is_active(uprobe))) {
> - ret = __uprobe_register(uprobe, uc);
> + consumer_add(uprobe, uc);
> + ret = register_for_each_vma(uprobe, uc);
> if (ret)
> __uprobe_unregister(uprobe, uc);
> }
> @@ -915,6 +933,12 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *
> goto retry;
> return ret;
> }
> +
> +int uprobe_register(struct inode *inode, loff_t offset,
> + struct uprobe_consumer *uc)
> +{
> + return __uprobe_register(inode, offset, uc);
> +}
> EXPORT_SYMBOL_GPL(uprobe_register);
>
> /*
> @@ -946,27 +970,6 @@ int uprobe_apply(struct inode *inode, loff_t offset,
> return ret;
> }
>
> -/*
> - * uprobe_unregister - unregister a already registered probe.
> - * @inode: the file in which the probe has to be removed.
> - * @offset: offset from the start of the file.
> - * @uc: identify which probe if multiple probes are colocated.
> - */
> -void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
> -{
> - struct uprobe *uprobe;
> -
> - uprobe = find_uprobe(inode, offset);
> - if (WARN_ON(!uprobe))
> - return;
> -
> - down_write(&uprobe->register_rwsem);
> - __uprobe_unregister(uprobe, uc);
> - up_write(&uprobe->register_rwsem);
> - put_uprobe(uprobe);
> -}
> -EXPORT_SYMBOL_GPL(uprobe_unregister);
> -
> static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
> {
> struct vm_area_struct *vma;
> --
> 2.14.4
>