From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH V4 2/2] ptr_ring: try vmalloc() when kmalloc() fails Date: Fri, 9 Feb 2018 17:53:50 +0200 Message-ID: <20180209173914-mutt-send-email-mst@kernel.org> References: <1518169550-5987-1-git-send-email-jasowang@redhat.com> <1518169550-5987-2-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Jason Wang Return-path: Content-Disposition: inline In-Reply-To: <1518169550-5987-2-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, Feb 09, 2018 at 05:45:50PM +0800, Jason Wang wrote: > This patch switch to use kvmalloc_array() for using a vmalloc() > fallback to help in case kmalloc() fails. Above isn't really saying anything about the motivation, it just explains what kvmalloc_array does. How about: Switch ptr_ring from kmalloc to kvmalloc. This way it can support larger ring sizes. > > Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com > Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") I don't see this as a bugfix - it's more of an enhancement. Do we need this in net or can we defer this to net-next? I'm not sure myself. For now Acked-by: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > include/linux/ptr_ring.h | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h > index 6051a5f..b884b77 100644 > --- a/include/linux/ptr_ring.h > +++ b/include/linux/ptr_ring.h > @@ -464,11 +464,14 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r, > __PTR_RING_PEEK_CALL_v; \ > }) > > +/* Not all gfp_t flags (besides GFP_KERNEL) are allowed. See > + * documentation for vmalloc for which of them are legal. > + */ > static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp) > { > if (size * sizeof(void *) > KMALLOC_MAX_SIZE) > return NULL; > - return kcalloc(size, sizeof(void *), gfp); > + return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO); > } > > static inline void __ptr_ring_set_size(struct ptr_ring *r, int size) > @@ -603,7 +606,7 @@ static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp, > spin_unlock(&(r)->producer_lock); > spin_unlock_irqrestore(&(r)->consumer_lock, flags); > > - kfree(old); > + kvfree(old); > > return 0; > } > @@ -643,7 +646,7 @@ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, > } > > for (i = 0; i < nrings; ++i) > - kfree(queues[i]); > + kvfree(queues[i]); > > kfree(queues); > > @@ -651,7 +654,7 @@ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, > > nomem: > while (--i >= 0) > - kfree(queues[i]); > + kvfree(queues[i]); > > kfree(queues); > > @@ -666,7 +669,7 @@ static inline void ptr_ring_cleanup(struct ptr_ring *r, void (*destroy)(void *)) > if (destroy) > while ((ptr = ptr_ring_consume(r))) > destroy(ptr); > - kfree(r->queue); > + kvfree(r->queue); > } > > #endif /* _LINUX_PTR_RING_H */ > -- > 2.7.4