Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Christoph Hellwig]

On Thu, Apr 05, 2018 at 09:07:49AM -0700, Vadim Lomovtsev wrote:
> > 
> > > + mc_list = kmalloc(sizeof(*mc_list) +
> > > +   sizeof(u64) * 
> > > netdev_mc_count(netdev),
> > > +   GFP_ATOMIC);
> > 
> > kmalloc_array(), please.
> 
> In this case it would require two memory allocation calls to kmalloc() for
> xcast_addr_list struct and to kmalloc_array() for 'mc' addresses, becasue of
> different data types and so two null-ptr checks .. this is what I'd like get 
> rid off.
> 
> My idea of this was to keep number of array elements and themselves within the
> same memory block/page to reduce number of memory allocation requests, number
> of allocated pages/blocks and avoid possible memory fragmentation (however, I 
> believe
> the latter is already handled at the mm layer).

Indeed, lets keep it as-is.

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Christoph Hellwig]

On Thu, Apr 05, 2018 at 09:07:49AM -0700, Vadim Lomovtsev wrote:
> > 
> > > + mc_list = kmalloc(sizeof(*mc_list) +
> > > +   sizeof(u64) * 
> > > netdev_mc_count(netdev),
> > > +   GFP_ATOMIC);
> > 
> > kmalloc_array(), please.
> 
> In this case it would require two memory allocation calls to kmalloc() for
> xcast_addr_list struct and to kmalloc_array() for 'mc' addresses, becasue of
> different data types and so two null-ptr checks .. this is what I'd like get 
> rid off.
> 
> My idea of this was to keep number of array elements and themselves within the
> same memory block/page to reduce number of memory allocation requests, number
> of allocated pages/blocks and avoid possible memory fragmentation (however, I 
> believe
> the latter is already handled at the mm layer).

Indeed, lets keep it as-is.

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Vadim Lomovtsev]

Hi Christoph,

Thank you for your feedback and time.

On Thu, Apr 05, 2018 at 08:07:48AM -0700, Christoph Hellwig wrote:
> >  struct xcast_addr_list {
> > -   struct list_head list;
> > int  count;
> > +   u64  mc[0];
> 
> Please use the standard C99 syntax here:
> 
>   u64  mc[];

Ok, will update.

> 
> > +   mc_list = kmalloc(sizeof(*mc_list) +
> > + sizeof(u64) * 
> > netdev_mc_count(netdev),
> > + GFP_ATOMIC);
> 
> kmalloc_array(), please.

In this case it would require two memory allocation calls to kmalloc() for
xcast_addr_list struct and to kmalloc_array() for 'mc' addresses, becasue of
different data types and so two null-ptr checks .. this is what I'd like get 
rid off.

My idea of this was to keep number of array elements and themselves within the
same memory block/page to reduce number of memory allocation requests, number
of allocated pages/blocks and avoid possible memory fragmentation (however, I 
believe
the latter is already handled at the mm layer).

WBR,
Vadim

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Vadim Lomovtsev]

Hi Christoph,

Thank you for your feedback and time.

On Thu, Apr 05, 2018 at 08:07:48AM -0700, Christoph Hellwig wrote:
> >  struct xcast_addr_list {
> > -   struct list_head list;
> > int  count;
> > +   u64  mc[0];
> 
> Please use the standard C99 syntax here:
> 
>   u64  mc[];

Ok, will update.

> 
> > +   mc_list = kmalloc(sizeof(*mc_list) +
> > + sizeof(u64) * 
> > netdev_mc_count(netdev),
> > + GFP_ATOMIC);
> 
> kmalloc_array(), please.

In this case it would require two memory allocation calls to kmalloc() for
xcast_addr_list struct and to kmalloc_array() for 'mc' addresses, becasue of
different data types and so two null-ptr checks .. this is what I'd like get 
rid off.

My idea of this was to keep number of array elements and themselves within the
same memory block/page to reduce number of memory allocation requests, number
of allocated pages/blocks and avoid possible memory fragmentation (however, I 
believe
the latter is already handled at the mm layer).

WBR,
Vadim

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Christoph Hellwig]

>  struct xcast_addr_list {
> - struct list_head list;
>   int  count;
> + u64  mc[0];

Please use the standard C99 syntax here:

u64  mc[];

> + mc_list = kmalloc(sizeof(*mc_list) +
> +   sizeof(u64) * 
> netdev_mc_count(netdev),
> +   GFP_ATOMIC);

kmalloc_array(), please.

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Christoph Hellwig]

>  struct xcast_addr_list {
> - struct list_head list;
>   int  count;
> + u64  mc[0];

Please use the standard C99 syntax here:

u64  mc[];

> + mc_list = kmalloc(sizeof(*mc_list) +
> +   sizeof(u64) * 
> netdev_mc_count(netdev),
> +   GFP_ATOMIC);

kmalloc_array(), please.

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Vadim Lomovtsev]

[correct Roberts' address]

On Thu, Apr 05, 2018 at 07:57:56AM -0700, Vadim Lomovtsev wrote:
> From: Vadim Lomovtsev 
> 
> It is too expensive to pass u64 values via linked list, instead
> allocate array for them by overall number of mac addresses from netdev.
> 
> This eventually removes multiple kmalloc() calls, aviod memory
> fragmentation and allow to put single null check on kmalloc
> return value in order to prevent a potential null pointer dereference.
> 
> Addresses-Coverity-ID: 1467429 ("Dereference null return value")
> Fixes: 37c3347eb247 ("net: thunderx: add ndo_set_rx_mode callback 
> implementation for VF")
> Signed-off-by: Vadim Lomovtsev 
> ---
>  drivers/net/ethernet/cavium/thunder/nic.h|  7 +-
>  drivers/net/ethernet/cavium/thunder/nicvf_main.c | 28 
> +---
>  2 files changed, 11 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cavium/thunder/nic.h 
> b/drivers/net/ethernet/cavium/thunder/nic.h
> index 5fc46c5a4f36..da052159f014 100644
> --- a/drivers/net/ethernet/cavium/thunder/nic.h
> +++ b/drivers/net/ethernet/cavium/thunder/nic.h
> @@ -265,14 +265,9 @@ struct nicvf_drv_stats {
>  
>  struct cavium_ptp;
>  
> -struct xcast_addr {
> - struct list_head list;
> - u64  addr;
> -};
> -
>  struct xcast_addr_list {
> - struct list_head list;
>   int  count;
> + u64  mc[0];
>  };
>  
>  struct nicvf_work {
> diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c 
> b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> index 1e9a31fef729..a26d8bc92e01 100644
> --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> @@ -1929,7 +1929,7 @@ static void nicvf_set_rx_mode_task(struct work_struct 
> *work_arg)
> work.work);
>   struct nicvf *nic = container_of(vf_work, struct nicvf, rx_mode_work);
>   union nic_mbx mbx = {};
> - struct xcast_addr *xaddr, *next;
> + u8 idx = 0;
>  
>   if (!vf_work)
>   return;
> @@ -1956,16 +1956,10 @@ static void nicvf_set_rx_mode_task(struct work_struct 
> *work_arg)
>   /* check if we have any specific MACs to be added to PF DMAC filter */
>   if (vf_work->mc) {
>   /* now go through kernel list of MACs and add them one by one */
> - list_for_each_entry_safe(xaddr, next,
> -  _work->mc->list, list) {
> + for (idx = 0; idx < vf_work->mc->count; idx++) {
>   mbx.xcast.msg = NIC_MBOX_MSG_ADD_MCAST;
> - mbx.xcast.data.mac = xaddr->addr;
> + mbx.xcast.data.mac = vf_work->mc->mc[idx];
>   nicvf_send_msg_to_pf(nic, );
> -
> - /* after receiving ACK from PF release memory */
> - list_del(>list);
> - kfree(xaddr);
> - vf_work->mc->count--;
>   }
>   kfree(vf_work->mc);
>   }
> @@ -1996,17 +1990,15 @@ static void nicvf_set_rx_mode(struct net_device 
> *netdev)
>   mode |= BGX_XCAST_MCAST_FILTER;
>   /* here we need to copy mc addrs */
>   if (netdev_mc_count(netdev)) {
> - struct xcast_addr *xaddr;
> -
> - mc_list = kmalloc(sizeof(*mc_list), GFP_ATOMIC);
> - INIT_LIST_HEAD(_list->list);
> + mc_list = kmalloc(sizeof(*mc_list) +
> +   sizeof(u64) * 
> netdev_mc_count(netdev),
> +   GFP_ATOMIC);
> + if (unlikely(!mc_list))
> + return;
> + mc_list->count = 0;
>   netdev_hw_addr_list_for_each(ha, >mc) {
> - xaddr = kmalloc(sizeof(*xaddr),
> - GFP_ATOMIC);
> - xaddr->addr =
> + mc_list->mc[mc_list->count] =
>   ether_addr_to_u64(ha->addr);
> - list_add_tail(>list,
> -   _list->list);
>   mc_list->count++;
>   }
>   }
> -- 
> 2.14.3
> 

Re: [PATCH] net: thunderx: rework mac addresses list to u64 array

[Vadim Lomovtsev]

[correct Roberts' address]

On Thu, Apr 05, 2018 at 07:57:56AM -0700, Vadim Lomovtsev wrote:
> From: Vadim Lomovtsev 
> 
> It is too expensive to pass u64 values via linked list, instead
> allocate array for them by overall number of mac addresses from netdev.
> 
> This eventually removes multiple kmalloc() calls, aviod memory
> fragmentation and allow to put single null check on kmalloc
> return value in order to prevent a potential null pointer dereference.
> 
> Addresses-Coverity-ID: 1467429 ("Dereference null return value")
> Fixes: 37c3347eb247 ("net: thunderx: add ndo_set_rx_mode callback 
> implementation for VF")
> Signed-off-by: Vadim Lomovtsev 
> ---
>  drivers/net/ethernet/cavium/thunder/nic.h|  7 +-
>  drivers/net/ethernet/cavium/thunder/nicvf_main.c | 28 
> +---
>  2 files changed, 11 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cavium/thunder/nic.h 
> b/drivers/net/ethernet/cavium/thunder/nic.h
> index 5fc46c5a4f36..da052159f014 100644
> --- a/drivers/net/ethernet/cavium/thunder/nic.h
> +++ b/drivers/net/ethernet/cavium/thunder/nic.h
> @@ -265,14 +265,9 @@ struct nicvf_drv_stats {
>  
>  struct cavium_ptp;
>  
> -struct xcast_addr {
> - struct list_head list;
> - u64  addr;
> -};
> -
>  struct xcast_addr_list {
> - struct list_head list;
>   int  count;
> + u64  mc[0];
>  };
>  
>  struct nicvf_work {
> diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c 
> b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> index 1e9a31fef729..a26d8bc92e01 100644
> --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
> @@ -1929,7 +1929,7 @@ static void nicvf_set_rx_mode_task(struct work_struct 
> *work_arg)
> work.work);
>   struct nicvf *nic = container_of(vf_work, struct nicvf, rx_mode_work);
>   union nic_mbx mbx = {};
> - struct xcast_addr *xaddr, *next;
> + u8 idx = 0;
>  
>   if (!vf_work)
>   return;
> @@ -1956,16 +1956,10 @@ static void nicvf_set_rx_mode_task(struct work_struct 
> *work_arg)
>   /* check if we have any specific MACs to be added to PF DMAC filter */
>   if (vf_work->mc) {
>   /* now go through kernel list of MACs and add them one by one */
> - list_for_each_entry_safe(xaddr, next,
> -  _work->mc->list, list) {
> + for (idx = 0; idx < vf_work->mc->count; idx++) {
>   mbx.xcast.msg = NIC_MBOX_MSG_ADD_MCAST;
> - mbx.xcast.data.mac = xaddr->addr;
> + mbx.xcast.data.mac = vf_work->mc->mc[idx];
>   nicvf_send_msg_to_pf(nic, );
> -
> - /* after receiving ACK from PF release memory */
> - list_del(>list);
> - kfree(xaddr);
> - vf_work->mc->count--;
>   }
>   kfree(vf_work->mc);
>   }
> @@ -1996,17 +1990,15 @@ static void nicvf_set_rx_mode(struct net_device 
> *netdev)
>   mode |= BGX_XCAST_MCAST_FILTER;
>   /* here we need to copy mc addrs */
>   if (netdev_mc_count(netdev)) {
> - struct xcast_addr *xaddr;
> -
> - mc_list = kmalloc(sizeof(*mc_list), GFP_ATOMIC);
> - INIT_LIST_HEAD(_list->list);
> + mc_list = kmalloc(sizeof(*mc_list) +
> +   sizeof(u64) * 
> netdev_mc_count(netdev),
> +   GFP_ATOMIC);
> + if (unlikely(!mc_list))
> + return;
> + mc_list->count = 0;
>   netdev_hw_addr_list_for_each(ha, >mc) {
> - xaddr = kmalloc(sizeof(*xaddr),
> - GFP_ATOMIC);
> - xaddr->addr =
> + mc_list->mc[mc_list->count] =
>   ether_addr_to_u64(ha->addr);
> - list_add_tail(>list,
> -   _list->list);
>   mc_list->count++;
>   }
>   }
> -- 
> 2.14.3
>