[openib-general] Re: [PATCH] roland-uverbs: possible race condition

[Michael S. Tsirkin]

Quoting r. Roland Dreier <roland at topspin.com>:
> Subject: Re: [openib-general] Re: [PATCH] roland-uverbs: possible race condition
> 
> Does this look reasonable?
> 
> Index: infiniband/hw/mthca/mthca_dev.h
> ===================================================================
> --- infiniband/hw/mthca/mthca_dev.h	(revision 1732)
> +++ infiniband/hw/mthca/mthca_dev.h	(working copy)
> @@ -171,6 +171,7 @@ struct mthca_eq_table {
>  	struct mthca_alloc alloc;
>  	void __iomem      *clr_int;
>  	u32                clr_mask;
> +	u32                arm_mask;
>  	struct mthca_eq    eq[MTHCA_NUM_EQ];
>  	u64                icm_virt;
>  	struct page       *icm_page;
> Index: infiniband/hw/mthca/mthca_eq.c
> ===================================================================
> --- infiniband/hw/mthca/mthca_eq.c	(revision 1732)
> +++ infiniband/hw/mthca/mthca_eq.c	(working copy)
> @@ -430,6 +430,7 @@ static irqreturn_t mthca_arbel_interrupt
>  {
>  	struct mthca_dev *dev = dev_ptr;
>  	u32 arm = 0;
> +	int work = 0;
>  	int i;
>  
>  	if (dev->eq_table.clr_mask)
> @@ -437,14 +438,14 @@ static irqreturn_t mthca_arbel_interrupt
>  
>  	for (i = 0; i < MTHCA_NUM_EQ; ++i)
>  		if (mthca_eq_int(dev, &dev->eq_table.eq[i])) {
> +			work = 1;
>  			arbel_set_eq_ci(dev, &dev->eq_table.eq[i],
>  					dev->eq_table.eq[i].cons_index);
> -			arm |= dev->eq_table.eq[i].eqn_mask;
>  		}
>  
> -	arbel_eq_req_not(dev, arm);
> +	arbel_eq_req_not(dev, dev->eq_table.arm_mask);
>  
> -	return IRQ_RETVAL(arm);
> +	return IRQ_RETVAL(work);
>  }
>  
>  static irqreturn_t mthca_arbel_msi_x_interrupt(int irq, void *eq_ptr,
> @@ -568,6 +569,8 @@ static int __devinit mthca_create_eq(str
>  	eq->eqn_mask   = swab32(1 << eq->eqn);
>  	eq->cons_index = 0;
>  
> +	dev->eq_table.arm_mask |= eq->eqn_mask;
> +
>  	mthca_dbg(dev, "Allocated EQ %d with %d entries\n",
>  		  eq->eqn, nent);
>  
> @@ -618,6 +621,8 @@ static void mthca_free_eq(struct mthca_d
>  		mthca_warn(dev, "HW2SW_EQ returned status 0x%02x\n",
>  			   status);
>  
> +	dev->eq_table.arm_mask &= ~eq->eqn_mask;
> +
>  	if (0) {
>  		mthca_dbg(dev, "Dumping EQ context %02x:\n", eq->eqn);
>  		for (i = 0; i < sizeof (struct mthca_eq_context) / 4; ++i) {
> @@ -846,6 +851,8 @@ int __devinit mthca_init_eq_table(struct
>  			(dev->eq_table.inta_pin < 31 ? 4 : 0);
>  	}
>  
> +	dev->eq_table.arm_mask = 0;
> +
>  	intr = (dev->mthca_flags & MTHCA_FLAG_MSI) ?
>  		128 : dev->eq_table.inta_pin;
>  
> 

Yes, very close to my patch.

-- 
MST - Michael S. Tsirkin