On 10/03/2017 04:48 PM, Hans Holmberg wrote:
> From: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
>
> The commit bf22e37a6413 ("mm: add vfree_atomic()") made vfree unsafe to
> call in atomic context (unless the call came from an interrupt) and
> introduced vfree_atomic that is safe to call in atomic context.
>
> So, since we're holding locks when freeing line metadata, we need to
> use the atomic version of vfree.
>
> Fix this by introducing an atomic variant of pblk_mfree and
> switching to that in pblk_line_meta_free.
>
> Signed-off-by: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
> ---
>
> The patch is for:
> https://github.com/OpenChannelSSD/linux branch for-4.15/pblk
>
> drivers/lightnvm/pblk-init.c | 3 ++-
> drivers/lightnvm/pblk.h | 8 ++++++++
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index c452478..3a191a6 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -396,7 +396,8 @@ static void pblk_line_meta_free(struct pblk *pblk)
> spin_lock(&l_mg->free_lock);
What's the point in holding ->free_lock here? It seems like it could be just dropped.
> for (i = 0; i < PBLK_DATA_LINES; i++) {
> kfree(l_mg->sline_meta[i]);
> - pblk_mfree(l_mg->eline_meta[i]->buf, l_mg->emeta_alloc_type);
> + pblk_mfree_atomic(l_mg->eline_meta[i]->buf,
> + l_mg->emeta_alloc_type);
> kfree(l_mg->eline_meta[i]);
> }
> spin_unlock(&l_mg->free_lock);
> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> index 03965da..93f98e3 100644
> --- a/drivers/lightnvm/pblk.h
> +++ b/drivers/lightnvm/pblk.h
> @@ -881,6 +881,14 @@ static inline void pblk_mfree(void *ptr, int type)
> vfree(ptr);
> }
>
> +static inline void pblk_mfree_atomic(void *ptr, int type)
> +{
> + if (type == PBLK_KMALLOC_META)
> + kfree(ptr);
> + else
> + vfree_atomic(ptr);
> +}
> +
> static inline struct nvm_rq *nvm_rq_from_c_ctx(void *c_ctx)
> {
> return c_ctx - sizeof(struct nvm_rq);
>
