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[PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

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  [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core Qais Yousef <qais.yousef@imgtec.com> - 2015-11-03 12:20 +0100
    Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to  irq core kbuild test robot <lkp@intel.com> - 2015-11-03 13:10 +0100
    Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to  irq core Thomas Gleixner <tglx@linutronix.de> - 2015-11-07 13:20 +0100
    Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to  irq core Thomas Gleixner <tglx@linutronix.de> - 2015-11-07 14:40 +0100
      Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to  irq core Qais Yousef <qais.yousef@imgtec.com> - 2015-11-09 11:20 +0100

#1261408 — [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

Add a generic mechanism to dynamically allocate an IPI.

With this change the user can call irq_reserve_ipi() to dynamically allocate an
IPI and use the associated virq to send one to 1 or more cpus.

Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
---
 include/linux/irqdomain.h |  6 +++
 kernel/irq/irqdomain.c    | 98 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 422b6a1617b8..9ba67bfe8ad2 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -39,6 +39,7 @@ struct irq_domain;
 struct of_device_id;
 struct irq_chip;
 struct irq_data;
+struct ipi_mask;
 
 /* Number of irqs reserved for a legacy isa controller */
 #define NUM_ISA_INTERRUPTS	16
@@ -333,6 +334,11 @@ int irq_domain_xlate_onetwocell(struct irq_domain *d, struct device_node *ctrlr,
 			const u32 *intspec, unsigned int intsize,
 			irq_hw_number_t *out_hwirq, unsigned int *out_type);
 
+/* IPI functions */
+unsigned int irq_reserve_ipi(struct irq_domain *domain,
+			     const struct ipi_mask *dest);
+void irq_destroy_ipi(unsigned int irq);
+
 /* V2 interfaces to support hierarchy IRQ domains. */
 extern struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
 						unsigned int virq);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 22aa9612ef7c..dd240914301d 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -852,6 +852,104 @@ static int irq_domain_alloc_descs(int virq, unsigned int cnt,
 	return virq;
 }
 
+/**
+ * irq_reserve_ipi() - setup an IPI to destination cpumask
+ * @domain: IPI domain
+ * @dest: cpumask of cpus to receive the IPI
+ *
+ * Allocate a virq that can be used to send IPI to any CPU in dest mask.
+ *
+ * On success it'll return linux irq number and 0 on failure
+ */
+unsigned int irq_reserve_ipi(struct irq_domain *domain,
+			     const struct ipi_mask *dest)
+{
+	struct irq_data *data;
+	unsigned int nr_irqs;
+	int virq, i;
+
+	if (domain == NULL) {
+		pr_warn("Must provide a valid IPI domain!\n");
+		return 0;
+	}
+
+	if (!irq_domain_is_ipi(domain)) {
+		pr_warn("Not an IPI domain!\n");
+		return 0;
+	}
+
+	/* always allocate a virq per cpu */
+	nr_irqs = ipi_mask_weight(dest);
+
+	virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE);
+	if (virq <= 0) {
+		pr_warn("Can't reserve IPI, failed to alloc descs\n");
+		return 0;
+	}
+
+	virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
+					(void *) dest, true);
+	if (virq <= 0) {
+		pr_warn("Can't reserve IPI, failed to alloc irqs\n");
+		goto free_descs;
+	}
+
+	for (i = virq; i < virq + nr_irqs; i++) {
+		data = irq_get_irq_data(i);
+		data->common->ipi_mask = ipi_mask_alloc(dest->nbits);
+		if (!data->common->ipi_mask)
+			goto free_ipi_mask;
+		ipi_mask_copy(data->common->ipi_mask, dest);
+	}
+
+	return virq;
+
+free_ipi_mask:
+	for (i = virq; i < virq + nr_irqs; i++) {
+		data = irq_get_irq_data(i);
+		ipi_mask_free(data->common->ipi_mask);
+	}
+free_descs:
+	irq_free_descs(virq, nr_irqs);
+	return 0;
+}
+
+/**
+ * irq_destroy_ipi() - unreserve an IPI that was previously allocated
+ * @irq: linux irq number to be destroyed
+ *
+ * Return the IPIs allocated with irq_reserve_ipi() to the system destroying all
+ * virqs associated with them.
+ */
+void irq_destroy_ipi(unsigned int irq)
+{
+	struct irq_data *data = irq_get_irq_data(irq);
+	struct irq_domain *domain;
+	unsigned int nr_irqs, i;
+
+	if (!irq || !data)
+		return;
+
+	domain = data->domain;
+	if (WARN_ON(domain == NULL))
+		return;
+
+	if (!irq_domain_is_ipi(domain)) {
+		pr_warn("Not an IPI domain!\n");
+		return;
+	}
+
+	nr_irqs = ipi_mask_weight(data->common->ipi_mask);
+	ipi_mask_free(data->common->ipi_mask);
+
+	for (i = irq + 1; i < irq + nr_irqs; i++) {
+		data = irq_get_irq_data(i);
+		ipi_mask_free(data->common->ipi_mask);
+	}
+
+	irq_domain_free_irqs(irq, nr_irqs);
+}
+
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 /**
  * irq_domain_create_hierarchy - Add a irqdomain into the hierarchy
-- 
2.1.0

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#1261447 — Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

[Multipart message — attachments visible in raw view] — view raw

Hi Qais,

[auto build test ERROR on tip/irq/core -- if it's inappropriate base, please suggest rules for selecting the more suitable base]

url:    https://github.com/0day-ci/linux/commits/Qais-Yousef/Implement-generic-IPI-support-mechanism/20151103-192028
config: mips-jz4740 (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=mips 

All errors (new ones prefixed by >>):

   kernel/irq/irqdomain.c: In function 'irq_reserve_ipi':
>> kernel/irq/irqdomain.c:890:9: error: implicit declaration of function '__irq_domain_alloc_irqs' [-Werror=implicit-function-declaration]
     virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
            ^
   kernel/irq/irqdomain.c: In function 'irq_destroy_ipi':
>> kernel/irq/irqdomain.c:950:2: error: implicit declaration of function 'irq_domain_free_irqs' [-Werror=implicit-function-declaration]
     irq_domain_free_irqs(irq, nr_irqs);
     ^
   cc1: some warnings being treated as errors

vim +/__irq_domain_alloc_irqs +890 kernel/irq/irqdomain.c

   884		virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE);
   885		if (virq <= 0) {
   886			pr_warn("Can't reserve IPI, failed to alloc descs\n");
   887			return 0;
   888		}
   889	
 > 890		virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
   891						(void *) dest, true);
   892		if (virq <= 0) {
   893			pr_warn("Can't reserve IPI, failed to alloc irqs\n");
   894			goto free_descs;
   895		}
   896	
   897		for (i = virq; i < virq + nr_irqs; i++) {
   898			data = irq_get_irq_data(i);
   899			data->common->ipi_mask = ipi_mask_alloc(dest->nbits);
   900			if (!data->common->ipi_mask)
   901				goto free_ipi_mask;
   902			ipi_mask_copy(data->common->ipi_mask, dest);
   903		}
   904	
   905		return virq;
   906	
   907	free_ipi_mask:
   908		for (i = virq; i < virq + nr_irqs; i++) {
   909			data = irq_get_irq_data(i);
   910			ipi_mask_free(data->common->ipi_mask);
   911		}
   912	free_descs:
   913		irq_free_descs(virq, nr_irqs);
   914		return 0;
   915	}
   916	
   917	/**
   918	 * irq_destroy_ipi() - unreserve an IPI that was previously allocated
   919	 * @irq: linux irq number to be destroyed
   920	 *
   921	 * Return the IPIs allocated with irq_reserve_ipi() to the system destroying all
   922	 * virqs associated with them.
   923	 */
   924	void irq_destroy_ipi(unsigned int irq)
   925	{
   926		struct irq_data *data = irq_get_irq_data(irq);
   927		struct irq_domain *domain;
   928		unsigned int nr_irqs, i;
   929	
   930		if (!irq || !data)
   931			return;
   932	
   933		domain = data->domain;
   934		if (WARN_ON(domain == NULL))
   935			return;
   936	
   937		if (!irq_domain_is_ipi(domain)) {
   938			pr_warn("Not an IPI domain!\n");
   939			return;
   940		}
   941	
   942		nr_irqs = ipi_mask_weight(data->common->ipi_mask);
   943		ipi_mask_free(data->common->ipi_mask);
   944	
   945		for (i = irq + 1; i < irq + nr_irqs; i++) {
   946			data = irq_get_irq_data(i);
   947			ipi_mask_free(data->common->ipi_mask);
   948		}
   949	
 > 950		irq_domain_free_irqs(irq, nr_irqs);
   951	}
   952	
   953	#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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#1264825 — Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

On Tue, 3 Nov 2015, Qais Yousef wrote:

> Add a generic mechanism to dynamically allocate an IPI.
> 
> With this change the user can call irq_reserve_ipi() to dynamically allocate an
> IPI and use the associated virq to send one to 1 or more cpus.

Please move that to ipi.c as well.

Thanks,

	tglx

 
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#1264837 — Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

On Tue, 3 Nov 2015, Qais Yousef wrote:
> +
> +	/* always allocate a virq per cpu */
> +	nr_irqs = ipi_mask_weight(dest);

That's not really a good assumption. Not all architectures need
seperate interrupt numbers / descriptors because they can allocate
from a per cpu interrupt space. We really want to handle that here as
well. So we need a flag in the IPI domain which tells us whether that
allocation needs to be weight(desc) or 1.

Thanks,

	tglx


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#1265533 — Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

On 11/07/2015 01:31 PM, Thomas Gleixner wrote:
> On Tue, 3 Nov 2015, Qais Yousef wrote:
>> +
>> +	/* always allocate a virq per cpu */
>> +	nr_irqs = ipi_mask_weight(dest);
> That's not really a good assumption. Not all architectures need
> seperate interrupt numbers / descriptors because they can allocate
> from a per cpu interrupt space. We really want to handle that here as
> well. So we need a flag in the IPI domain which tells us whether that
> allocation needs to be weight(desc) or 1.

OK. But is it bad to always allocate the weight? I thought allocating 
virqs is cheap, or maybe not?

Thanks,
Qais
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