diff mbox series

[net-next,v2,4/4] netdev: use napi_schedule bool instead of napi_schedule_prep/__napi_schedule

Message ID 20231003145150.2498-4-ansuelsmth@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net-next,v2,1/4] netdev: replace simple napi_schedule_prep/__napi_schedule to napi_schedule | expand

Checks

Context Check Description
netdev/series_format warning Series does not have a cover letter
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1364 this patch: 1364
netdev/cc_maintainers warning 4 maintainers not CCed: linux-mediatek@lists.infradead.org matthias.bgg@gmail.com angelogioacchino.delregno@collabora.com johannes.berg@intel.com
netdev/build_clang success Errors and warnings before: 1363 this patch: 1363
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1387 this patch: 1387
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 36 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Christian Marangi Oct. 3, 2023, 2:51 p.m. UTC
Replace if condition of napi_schedule_prep/__napi_schedule and use bool
from napi_schedule directly where possible.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/ethernet/atheros/atlx/atl1.c     | 4 +---
 drivers/net/ethernet/toshiba/tc35815.c       | 4 +---
 drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
 3 files changed, 3 insertions(+), 9 deletions(-)

Comments

Eric Dumazet Oct. 5, 2023, 4:16 p.m. UTC | #1
On Tue, Oct 3, 2023 at 8:36 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
>
> Replace if condition of napi_schedule_prep/__napi_schedule and use bool
> from napi_schedule directly where possible.
>
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/net/ethernet/atheros/atlx/atl1.c     | 4 +---
>  drivers/net/ethernet/toshiba/tc35815.c       | 4 +---
>  drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
>  3 files changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
> index 02aa6fd8ebc2..a9014d7932db 100644
> --- a/drivers/net/ethernet/atheros/atlx/atl1.c
> +++ b/drivers/net/ethernet/atheros/atlx/atl1.c
> @@ -2446,7 +2446,7 @@ static int atl1_rings_clean(struct napi_struct *napi, int budget)
>
>  static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
>  {
> -       if (!napi_schedule_prep(&adapter->napi))
> +       if (!napi_schedule(&adapter->napi))
>                 /* It is possible in case even the RX/TX ints are disabled via IMR
>                  * register the ISR bits are set anyway (but do not produce IRQ).
>                  * To handle such situation the napi functions used to check is
> @@ -2454,8 +2454,6 @@ static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
>                  */
>                 return 0;
>
> -       __napi_schedule(&adapter->napi);
> -
>         /*
>          * Disable RX/TX ints via IMR register if it is
>          * allowed. NAPI handler must reenable them in same
> diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
> index 14cf6ecf6d0d..a8b8a0e13f9a 100644
> --- a/drivers/net/ethernet/toshiba/tc35815.c
> +++ b/drivers/net/ethernet/toshiba/tc35815.c
> @@ -1436,9 +1436,7 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
>         if (!(dmactl & DMA_IntMask)) {
>                 /* disable interrupts */
>                 tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> -               if (napi_schedule_prep(&lp->napi))
> -                       __napi_schedule(&lp->napi);
> -               else {
> +               if (!napi_schedule(&lp->napi)) {
>                         printk(KERN_ERR "%s: interrupt taken in poll\n",
>                                dev->name);
>                         BUG();

Hmmm... could you also remove this BUG() ? I think this code path can be taken
if some applications are using busy polling.

Or simply rewrite this with the traditional

if (napi_schedule_prep(&lp->napi)) {
   /* disable interrupts */
   tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
    __napi_schedule(&lp->napi);
}



> diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
> index 23b5a0adcbd6..146bc7bd14fb 100644
> --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
> +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
> @@ -1660,9 +1660,7 @@ irqreturn_t iwl_pcie_irq_rx_msix_handler(int irq, void *dev_id)
>         IWL_DEBUG_ISR(trans, "[%d] Got interrupt\n", entry->entry);
>
>         local_bh_disable();
> -       if (napi_schedule_prep(&rxq->napi))
> -               __napi_schedule(&rxq->napi);
> -       else
> +       if (!napi_schedule(&rxq->napi))
>                 iwl_pcie_clear_irq(trans, entry->entry);

Same remark here about twisted logic.

>         local_bh_enable();
>
> --
> 2.40.1
>
Christian Marangi Oct. 6, 2023, 6:49 p.m. UTC | #2
On Thu, Oct 05, 2023 at 06:16:26PM +0200, Eric Dumazet wrote:
> On Tue, Oct 3, 2023 at 8:36 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
> >
> > Replace if condition of napi_schedule_prep/__napi_schedule and use bool
> > from napi_schedule directly where possible.
> >
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >  drivers/net/ethernet/atheros/atlx/atl1.c     | 4 +---
> >  drivers/net/ethernet/toshiba/tc35815.c       | 4 +---
> >  drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
> >  3 files changed, 3 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
> > index 02aa6fd8ebc2..a9014d7932db 100644
> > --- a/drivers/net/ethernet/atheros/atlx/atl1.c
> > +++ b/drivers/net/ethernet/atheros/atlx/atl1.c
> > @@ -2446,7 +2446,7 @@ static int atl1_rings_clean(struct napi_struct *napi, int budget)
> >
> >  static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> >  {
> > -       if (!napi_schedule_prep(&adapter->napi))
> > +       if (!napi_schedule(&adapter->napi))
> >                 /* It is possible in case even the RX/TX ints are disabled via IMR
> >                  * register the ISR bits are set anyway (but do not produce IRQ).
> >                  * To handle such situation the napi functions used to check is
> > @@ -2454,8 +2454,6 @@ static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> >                  */
> >                 return 0;
> >
> > -       __napi_schedule(&adapter->napi);
> > -
> >         /*
> >          * Disable RX/TX ints via IMR register if it is
> >          * allowed. NAPI handler must reenable them in same
> > diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
> > index 14cf6ecf6d0d..a8b8a0e13f9a 100644
> > --- a/drivers/net/ethernet/toshiba/tc35815.c
> > +++ b/drivers/net/ethernet/toshiba/tc35815.c
> > @@ -1436,9 +1436,7 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
> >         if (!(dmactl & DMA_IntMask)) {
> >                 /* disable interrupts */
> >                 tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > -               if (napi_schedule_prep(&lp->napi))
> > -                       __napi_schedule(&lp->napi);
> > -               else {
> > +               if (!napi_schedule(&lp->napi)) {
> >                         printk(KERN_ERR "%s: interrupt taken in poll\n",
> >                                dev->name);
> >                         BUG();
> 
> Hmmm... could you also remove this BUG() ? I think this code path can be taken
> if some applications are using busy polling.
> 
> Or simply rewrite this with the traditional
> 
> if (napi_schedule_prep(&lp->napi)) {
>    /* disable interrupts */
>    tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
>     __napi_schedule(&lp->napi);
> }
> 
>

Mhhh is it safe to do so? I mean it seems very wrong to print a warning
and BUG() instead of disabling the interrupt only if napi can be
scheduled... Maybe is very old code? The more I see this the more I see
problem... (randomly disabling the interrupt and then make the kernel
die)

> 
> > diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
> > index 23b5a0adcbd6..146bc7bd14fb 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
> > +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
> > @@ -1660,9 +1660,7 @@ irqreturn_t iwl_pcie_irq_rx_msix_handler(int irq, void *dev_id)
> >         IWL_DEBUG_ISR(trans, "[%d] Got interrupt\n", entry->entry);
> >
> >         local_bh_disable();
> > -       if (napi_schedule_prep(&rxq->napi))
> > -               __napi_schedule(&rxq->napi);
> > -       else
> > +       if (!napi_schedule(&rxq->napi))
> >                 iwl_pcie_clear_irq(trans, entry->entry);
> 
> Same remark here about twisted logic.
> 

Ehhh here we need to be careful... We can do the usual prep/__schedule
with the DMA disable in between...

From the comments of iwl_pcie_clear_irq.

	/*
	 * Before sending the interrupt the HW disables it to prevent
	 * a nested interrupt. This is done by writing 1 to the corresponding
	 * bit in the mask register. After handling the interrupt, it should be
	 * re-enabled by clearing this bit. This register is defined as
	 * write 1 clear (W1C) register, meaning that it's being clear
	 * by writing 1 to the bit.
	 */

So the device disable the interrupt after being fired and the bit needs
to set again for the interrupt to be reenabled. So the function
correctly reenable the irq if a napi can't be scheduled... Think there
isn't another way to handle this.

> >         local_bh_enable();
> >
> > --
> > 2.40.1
> >
Eric Dumazet Oct. 8, 2023, 7:08 a.m. UTC | #3
On Fri, Oct 6, 2023 at 8:49 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
>
> On Thu, Oct 05, 2023 at 06:16:26PM +0200, Eric Dumazet wrote:
> > On Tue, Oct 3, 2023 at 8:36 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
> > >
> > > Replace if condition of napi_schedule_prep/__napi_schedule and use bool
> > > from napi_schedule directly where possible.
> > >
> > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > > ---
> > >  drivers/net/ethernet/atheros/atlx/atl1.c     | 4 +---
> > >  drivers/net/ethernet/toshiba/tc35815.c       | 4 +---
> > >  drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
> > >  3 files changed, 3 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > index 02aa6fd8ebc2..a9014d7932db 100644
> > > --- a/drivers/net/ethernet/atheros/atlx/atl1.c
> > > +++ b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > @@ -2446,7 +2446,7 @@ static int atl1_rings_clean(struct napi_struct *napi, int budget)
> > >
> > >  static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > >  {
> > > -       if (!napi_schedule_prep(&adapter->napi))
> > > +       if (!napi_schedule(&adapter->napi))
> > >                 /* It is possible in case even the RX/TX ints are disabled via IMR
> > >                  * register the ISR bits are set anyway (but do not produce IRQ).
> > >                  * To handle such situation the napi functions used to check is
> > > @@ -2454,8 +2454,6 @@ static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > >                  */
> > >                 return 0;
> > >
> > > -       __napi_schedule(&adapter->napi);
> > > -
> > >         /*
> > >          * Disable RX/TX ints via IMR register if it is
> > >          * allowed. NAPI handler must reenable them in same
> > > diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
> > > index 14cf6ecf6d0d..a8b8a0e13f9a 100644
> > > --- a/drivers/net/ethernet/toshiba/tc35815.c
> > > +++ b/drivers/net/ethernet/toshiba/tc35815.c
> > > @@ -1436,9 +1436,7 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
> > >         if (!(dmactl & DMA_IntMask)) {
> > >                 /* disable interrupts */
> > >                 tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > > -               if (napi_schedule_prep(&lp->napi))
> > > -                       __napi_schedule(&lp->napi);
> > > -               else {
> > > +               if (!napi_schedule(&lp->napi)) {
> > >                         printk(KERN_ERR "%s: interrupt taken in poll\n",
> > >                                dev->name);
> > >                         BUG();
> >
> > Hmmm... could you also remove this BUG() ? I think this code path can be taken
> > if some applications are using busy polling.
> >
> > Or simply rewrite this with the traditional
> >
> > if (napi_schedule_prep(&lp->napi)) {
> >    /* disable interrupts */
> >    tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> >     __napi_schedule(&lp->napi);
> > }
> >
> >
>
> Mhhh is it safe to do so? I mean it seems very wrong to print a warning
> and BUG() instead of disabling the interrupt only if napi can be
> scheduled... Maybe is very old code? The more I see this the more I see
> problem... (randomly disabling the interrupt and then make the kernel
> die)

I am pretty sure this BUG() can be hit these days with busy polling or
setting gro_flush_timeout.

I wish we could remove these bugs before someone copy-paste them.

Again, this is orthogonal, I might simply stop doing reviews if this
is not useful.
Christian Marangi Oct. 8, 2023, 6:27 p.m. UTC | #4
On Sun, Oct 08, 2023 at 09:08:41AM +0200, Eric Dumazet wrote:
> On Fri, Oct 6, 2023 at 8:49 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
> >
> > On Thu, Oct 05, 2023 at 06:16:26PM +0200, Eric Dumazet wrote:
> > > On Tue, Oct 3, 2023 at 8:36 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
> > > >
> > > > Replace if condition of napi_schedule_prep/__napi_schedule and use bool
> > > > from napi_schedule directly where possible.
> > > >
> > > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > > > ---
> > > >  drivers/net/ethernet/atheros/atlx/atl1.c     | 4 +---
> > > >  drivers/net/ethernet/toshiba/tc35815.c       | 4 +---
> > > >  drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
> > > >  3 files changed, 3 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > index 02aa6fd8ebc2..a9014d7932db 100644
> > > > --- a/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > +++ b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > @@ -2446,7 +2446,7 @@ static int atl1_rings_clean(struct napi_struct *napi, int budget)
> > > >
> > > >  static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > > >  {
> > > > -       if (!napi_schedule_prep(&adapter->napi))
> > > > +       if (!napi_schedule(&adapter->napi))
> > > >                 /* It is possible in case even the RX/TX ints are disabled via IMR
> > > >                  * register the ISR bits are set anyway (but do not produce IRQ).
> > > >                  * To handle such situation the napi functions used to check is
> > > > @@ -2454,8 +2454,6 @@ static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > > >                  */
> > > >                 return 0;
> > > >
> > > > -       __napi_schedule(&adapter->napi);
> > > > -
> > > >         /*
> > > >          * Disable RX/TX ints via IMR register if it is
> > > >          * allowed. NAPI handler must reenable them in same
> > > > diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
> > > > index 14cf6ecf6d0d..a8b8a0e13f9a 100644
> > > > --- a/drivers/net/ethernet/toshiba/tc35815.c
> > > > +++ b/drivers/net/ethernet/toshiba/tc35815.c
> > > > @@ -1436,9 +1436,7 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
> > > >         if (!(dmactl & DMA_IntMask)) {
> > > >                 /* disable interrupts */
> > > >                 tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > > > -               if (napi_schedule_prep(&lp->napi))
> > > > -                       __napi_schedule(&lp->napi);
> > > > -               else {
> > > > +               if (!napi_schedule(&lp->napi)) {
> > > >                         printk(KERN_ERR "%s: interrupt taken in poll\n",
> > > >                                dev->name);
> > > >                         BUG();
> > >
> > > Hmmm... could you also remove this BUG() ? I think this code path can be taken
> > > if some applications are using busy polling.
> > >
> > > Or simply rewrite this with the traditional
> > >
> > > if (napi_schedule_prep(&lp->napi)) {
> > >    /* disable interrupts */
> > >    tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > >     __napi_schedule(&lp->napi);
> > > }
> > >
> > >
> >
> > Mhhh is it safe to do so? I mean it seems very wrong to print a warning
> > and BUG() instead of disabling the interrupt only if napi can be
> > scheduled... Maybe is very old code? The more I see this the more I see
> > problem... (randomly disabling the interrupt and then make the kernel
> > die)
> 
> I am pretty sure this BUG() can be hit these days with busy polling or
> setting gro_flush_timeout.
> 
> I wish we could remove these bugs before someone copy-paste them.
> 
> Again, this is orthogonal, I might simply stop doing reviews if this
> is not useful.

They are very useful and thanks a lot for them! I'm asking these as to
understand how to proceed. I have in queue 2 other series that depends
on this and I'm just asking info on how to speedup the progress on this!

Soo think I have to send v3 with the suggested change and BUG() dropped?
Happy to do everything to fix and improve this series!
Eric Dumazet Oct. 9, 2023, 8:27 a.m. UTC | #5
On Sun, Oct 8, 2023 at 8:27 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
>
> On Sun, Oct 08, 2023 at 09:08:41AM +0200, Eric Dumazet wrote:
> > On Fri, Oct 6, 2023 at 8:49 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
> > >
> > > On Thu, Oct 05, 2023 at 06:16:26PM +0200, Eric Dumazet wrote:
> > > > On Tue, Oct 3, 2023 at 8:36 PM Christian Marangi <ansuelsmth@gmail.com> wrote:
> > > > >
> > > > > Replace if condition of napi_schedule_prep/__napi_schedule and use bool
> > > > > from napi_schedule directly where possible.
> > > > >
> > > > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > > > > ---
> > > > >  drivers/net/ethernet/atheros/atlx/atl1.c     | 4 +---
> > > > >  drivers/net/ethernet/toshiba/tc35815.c       | 4 +---
> > > > >  drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
> > > > >  3 files changed, 3 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > > index 02aa6fd8ebc2..a9014d7932db 100644
> > > > > --- a/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > > +++ b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > > @@ -2446,7 +2446,7 @@ static int atl1_rings_clean(struct napi_struct *napi, int budget)
> > > > >
> > > > >  static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > > > >  {
> > > > > -       if (!napi_schedule_prep(&adapter->napi))
> > > > > +       if (!napi_schedule(&adapter->napi))
> > > > >                 /* It is possible in case even the RX/TX ints are disabled via IMR
> > > > >                  * register the ISR bits are set anyway (but do not produce IRQ).
> > > > >                  * To handle such situation the napi functions used to check is
> > > > > @@ -2454,8 +2454,6 @@ static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > > > >                  */
> > > > >                 return 0;
> > > > >
> > > > > -       __napi_schedule(&adapter->napi);
> > > > > -
> > > > >         /*
> > > > >          * Disable RX/TX ints via IMR register if it is
> > > > >          * allowed. NAPI handler must reenable them in same
> > > > > diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
> > > > > index 14cf6ecf6d0d..a8b8a0e13f9a 100644
> > > > > --- a/drivers/net/ethernet/toshiba/tc35815.c
> > > > > +++ b/drivers/net/ethernet/toshiba/tc35815.c
> > > > > @@ -1436,9 +1436,7 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
> > > > >         if (!(dmactl & DMA_IntMask)) {
> > > > >                 /* disable interrupts */
> > > > >                 tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > > > > -               if (napi_schedule_prep(&lp->napi))
> > > > > -                       __napi_schedule(&lp->napi);
> > > > > -               else {
> > > > > +               if (!napi_schedule(&lp->napi)) {
> > > > >                         printk(KERN_ERR "%s: interrupt taken in poll\n",
> > > > >                                dev->name);
> > > > >                         BUG();
> > > >
> > > > Hmmm... could you also remove this BUG() ? I think this code path can be taken
> > > > if some applications are using busy polling.
> > > >
> > > > Or simply rewrite this with the traditional
> > > >
> > > > if (napi_schedule_prep(&lp->napi)) {
> > > >    /* disable interrupts */
> > > >    tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > > >     __napi_schedule(&lp->napi);
> > > > }
> > > >
> > > >
> > >
> > > Mhhh is it safe to do so? I mean it seems very wrong to print a warning
> > > and BUG() instead of disabling the interrupt only if napi can be
> > > scheduled... Maybe is very old code? The more I see this the more I see
> > > problem... (randomly disabling the interrupt and then make the kernel
> > > die)
> >
> > I am pretty sure this BUG() can be hit these days with busy polling or
> > setting gro_flush_timeout.
> >
> > I wish we could remove these bugs before someone copy-paste them.
> >
> > Again, this is orthogonal, I might simply stop doing reviews if this
> > is not useful.
>
> They are very useful and thanks a lot for them! I'm asking these as to
> understand how to proceed. I have in queue 2 other series that depends
> on this and I'm just asking info on how to speedup the progress on this!
>
> Soo think I have to send v3 with the suggested change and BUG() dropped?
> Happy to do everything to fix and improve this series!

I think that your patch series is all about doing cleanups,
so I suggested adding another cleanup/fix,
and this can be done independently.

I doubt this matters, this code has probably not been used for quite a
long time...
diff mbox series

Patch

diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
index 02aa6fd8ebc2..a9014d7932db 100644
--- a/drivers/net/ethernet/atheros/atlx/atl1.c
+++ b/drivers/net/ethernet/atheros/atlx/atl1.c
@@ -2446,7 +2446,7 @@  static int atl1_rings_clean(struct napi_struct *napi, int budget)
 
 static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
 {
-	if (!napi_schedule_prep(&adapter->napi))
+	if (!napi_schedule(&adapter->napi))
 		/* It is possible in case even the RX/TX ints are disabled via IMR
 		 * register the ISR bits are set anyway (but do not produce IRQ).
 		 * To handle such situation the napi functions used to check is
@@ -2454,8 +2454,6 @@  static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
 		 */
 		return 0;
 
-	__napi_schedule(&adapter->napi);
-
 	/*
 	 * Disable RX/TX ints via IMR register if it is
 	 * allowed. NAPI handler must reenable them in same
diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
index 14cf6ecf6d0d..a8b8a0e13f9a 100644
--- a/drivers/net/ethernet/toshiba/tc35815.c
+++ b/drivers/net/ethernet/toshiba/tc35815.c
@@ -1436,9 +1436,7 @@  static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
 	if (!(dmactl & DMA_IntMask)) {
 		/* disable interrupts */
 		tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
-		if (napi_schedule_prep(&lp->napi))
-			__napi_schedule(&lp->napi);
-		else {
+		if (!napi_schedule(&lp->napi)) {
 			printk(KERN_ERR "%s: interrupt taken in poll\n",
 			       dev->name);
 			BUG();
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 23b5a0adcbd6..146bc7bd14fb 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1660,9 +1660,7 @@  irqreturn_t iwl_pcie_irq_rx_msix_handler(int irq, void *dev_id)
 	IWL_DEBUG_ISR(trans, "[%d] Got interrupt\n", entry->entry);
 
 	local_bh_disable();
-	if (napi_schedule_prep(&rxq->napi))
-		__napi_schedule(&rxq->napi);
-	else
+	if (!napi_schedule(&rxq->napi))
 		iwl_pcie_clear_irq(trans, entry->entry);
 	local_bh_enable();