Currently, the MANA driver allocates pci vector statically based on
MANA_MAX_NUM_QUEUES and num_online_cpus() values and in some cases ends
up allocating more vectors than it needs.
This is because, by this time we do not have a HW channel and do not know
how many IRQs should be allocated.
To avoid this, we allocate 1 IRQ vector during the creation of HWC and
after getting the value supported by hardware, dynamically add the
remaining vectors.

Signed-off-by: Shradha Gupta <shradhagu...@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
---
 .../net/ethernet/microsoft/mana/gdma_main.c   | 306 ++++++++++++++----
 include/net/mana/gdma.h                       |   5 +-
 2 files changed, 250 insertions(+), 61 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c 
b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 4ffaf7588885..3e3b5854b736 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -6,6 +6,9 @@
 #include <linux/pci.h>
 #include <linux/utsname.h>
 #include <linux/version.h>
+#include <linux/msi.h>
+#include <linux/irqdomain.h>
+#include <linux/list.h>
 
 #include <net/mana/mana.h>
 
@@ -80,8 +83,15 @@ static int mana_gd_query_max_resources(struct pci_dev *pdev)
                return err ? err : -EPROTO;
        }
 
-       if (gc->num_msix_usable > resp.max_msix)
-               gc->num_msix_usable = resp.max_msix;
+       if (!pci_msix_can_alloc_dyn(pdev)) {
+               if (gc->num_msix_usable > resp.max_msix)
+                       gc->num_msix_usable = resp.max_msix;
+       } else {
+               /* If dynamic allocation is enabled we have already allocated
+                * hwc msi
+                */
+               gc->num_msix_usable = min(resp.max_msix, num_online_cpus() + 1);
+       }
 
        if (gc->num_msix_usable <= 1)
                return -ENOSPC;
@@ -465,9 +475,10 @@ static int mana_gd_register_irq(struct gdma_queue *queue,
        struct gdma_irq_context *gic;
        struct gdma_context *gc;
        unsigned int msi_index;
-       unsigned long flags;
+       struct list_head *pos;
+       unsigned long flags, flag_irq;
        struct device *dev;
-       int err = 0;
+       int err = 0, count;
 
        gc = gd->gdma_context;
        dev = gc->dev;
@@ -482,7 +493,22 @@ static int mana_gd_register_irq(struct gdma_queue *queue,
        }
 
        queue->eq.msix_index = msi_index;
-       gic = &gc->irq_contexts[msi_index];
+
+       /* get the msi_index value from the list*/
+       count = 0;
+       spin_lock_irqsave(&gc->irq_ctxs_lock, flag_irq);
+       list_for_each(pos, &gc->irq_contexts) {
+               if (count == msi_index) {
+                       gic = list_entry(pos, struct gdma_irq_context, 
gic_list);
+                       break;
+               }
+
+               count++;
+       }
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flag_irq);
+
+       if (!gic)
+               return -1;
 
        spin_lock_irqsave(&gic->lock, flags);
        list_add_rcu(&queue->entry, &gic->eq_list);
@@ -497,8 +523,10 @@ static void mana_gd_deregiser_irq(struct gdma_queue *queue)
        struct gdma_irq_context *gic;
        struct gdma_context *gc;
        unsigned int msix_index;
-       unsigned long flags;
+       struct list_head *pos;
+       unsigned long flags, flag_irq;
        struct gdma_queue *eq;
+       int count;
 
        gc = gd->gdma_context;
 
@@ -507,7 +535,22 @@ static void mana_gd_deregiser_irq(struct gdma_queue *queue)
        if (WARN_ON(msix_index >= gc->num_msix_usable))
                return;
 
-       gic = &gc->irq_contexts[msix_index];
+       /* get the msi_index value from the list*/
+       count = 0;
+       spin_lock_irqsave(&gc->irq_ctxs_lock, flag_irq);
+       list_for_each(pos, &gc->irq_contexts) {
+               if (count == msix_index) {
+                       gic = list_entry(pos, struct gdma_irq_context, 
gic_list);
+                       break;
+               }
+
+               count++;
+       }
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flag_irq);
+
+       if (!gic)
+               return;
+
        spin_lock_irqsave(&gic->lock, flags);
        list_for_each_entry_rcu(eq, &gic->eq_list, entry) {
                if (queue == eq) {
@@ -1288,11 +1331,11 @@ void mana_gd_free_res_map(struct gdma_resource *r)
        r->size = 0;
 }
 
-static int irq_setup(unsigned int *irqs, unsigned int len, int node)
+static int irq_setup(unsigned int *irqs, unsigned int len, int node, int 
skip_cpu)
 {
        const struct cpumask *next, *prev = cpu_none_mask;
        cpumask_var_t cpus __free(free_cpumask_var);
-       int cpu, weight;
+       int cpu, weight, i = 0;
 
        if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
                return -ENOMEM;
@@ -1303,9 +1346,21 @@ static int irq_setup(unsigned int *irqs, unsigned int 
len, int node)
                while (weight > 0) {
                        cpumask_andnot(cpus, next, prev);
                        for_each_cpu(cpu, cpus) {
+                               /* If the call is made for irqs which are 
dynamically
+                                * added and the num of vcpus is more or equal 
to
+                                * allocated msix, we need to skip the first
+                                * set of cpus, since they are already 
affinitized
+                                * to HWC IRQ
+                                */
+                               if (skip_cpu && !i) {
+                                       i = 1;
+                                       goto next_cpumask;
+                               }
                                if (len-- == 0)
                                        goto done;
+
                                irq_set_affinity_and_hint(*irqs++, 
topology_sibling_cpumask(cpu));
+next_cpumask:
                                cpumask_andnot(cpus, cpus, 
topology_sibling_cpumask(cpu));
                                --weight;
                        }
@@ -1317,29 +1372,92 @@ static int irq_setup(unsigned int *irqs, unsigned int 
len, int node)
        return 0;
 }
 
-static int mana_gd_setup_irqs(struct pci_dev *pdev)
+static int mana_gd_setup_dyn_irqs(struct pci_dev *pdev, int nvec)
 {
        struct gdma_context *gc = pci_get_drvdata(pdev);
-       unsigned int max_queues_per_port;
        struct gdma_irq_context *gic;
-       unsigned int max_irqs, cpu;
-       int start_irq_index = 1;
-       int nvec, *irqs, irq;
+       int *irqs, irq, skip_first_cpu = 0;
+       unsigned long flags;
        int err, i = 0, j;
 
        cpus_read_lock();
-       max_queues_per_port = num_online_cpus();
-       if (max_queues_per_port > MANA_MAX_NUM_QUEUES)
-               max_queues_per_port = MANA_MAX_NUM_QUEUES;
+       spin_lock_irqsave(&gc->irq_ctxs_lock, flags);
+       irqs = kmalloc_array(nvec, sizeof(int), GFP_KERNEL);
+       if (!irqs) {
+               err = -ENOMEM;
+               goto free_irq_vector;
+       }
 
-       /* Need 1 interrupt for the Hardware communication Channel (HWC) */
-       max_irqs = max_queues_per_port + 1;
+       for (i = 0; i < nvec; i++) {
+               gic = kcalloc(1, sizeof(struct gdma_irq_context), GFP_KERNEL);
+               if (!gic) {
+                       err = -ENOMEM;
+                       goto free_irq;
+               }
+               gic->handler = mana_gd_process_eq_events;
+               INIT_LIST_HEAD(&gic->eq_list);
+               spin_lock_init(&gic->lock);
 
-       nvec = pci_alloc_irq_vectors(pdev, 2, max_irqs, PCI_IRQ_MSIX);
-       if (nvec < 0) {
-               cpus_read_unlock();
-               return nvec;
+               snprintf(gic->name, MANA_IRQ_NAME_SZ, "mana_q%d@pci:%s",
+                        i, pci_name(pdev));
+
+               /* one pci vector is already allocated for HWC */
+               irqs[i] = pci_irq_vector(pdev, i + 1);
+               if (irqs[i] < 0) {
+                       err = irqs[i];
+                       goto free_current_gic;
+               }
+
+               err = request_irq(irqs[i], mana_gd_intr, 0, gic->name, gic);
+               if (err)
+                       goto free_current_gic;
+
+               list_add_tail(&gic->gic_list, &gc->irq_contexts);
+       }
+
+       if (gc->num_msix_usable <= num_online_cpus())
+               skip_first_cpu = 1;
+
+       err = irq_setup(irqs, nvec, gc->numa_node, skip_first_cpu);
+       if (err)
+               goto free_irq;
+
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flags);
+       cpus_read_unlock();
+       kfree(irqs);
+       return 0;
+
+free_current_gic:
+       kfree(gic);
+free_irq:
+       for (j = i - 1; j >= 0; j--) {
+               irq = pci_irq_vector(pdev, j + 1);
+               gic = list_last_entry(&gc->irq_contexts, struct 
gdma_irq_context, gic_list);
+               irq_update_affinity_hint(irq, NULL);
+               free_irq(irq, gic);
+               list_del(&gic->gic_list);
+               kfree(gic);
        }
+       kfree(irqs);
+free_irq_vector:
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flags);
+       cpus_read_unlock();
+       return err;
+}
+
+static int mana_gd_setup_irqs(struct pci_dev *pdev, int nvec)
+{
+       struct gdma_context *gc = pci_get_drvdata(pdev);
+       struct gdma_irq_context *gic;
+       int start_irq_index = 1;
+       unsigned long flags;
+       unsigned int cpu;
+       int *irqs, irq;
+       int err, i = 0, j;
+
+       cpus_read_lock();
+       spin_lock_irqsave(&gc->irq_ctxs_lock, flags);
+
        if (nvec <= num_online_cpus())
                start_irq_index = 0;
 
@@ -1349,15 +1467,12 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev)
                goto free_irq_vector;
        }
 
-       gc->irq_contexts = kcalloc(nvec, sizeof(struct gdma_irq_context),
-                                  GFP_KERNEL);
-       if (!gc->irq_contexts) {
-               err = -ENOMEM;
-               goto free_irq_array;
-       }
-
        for (i = 0; i < nvec; i++) {
-               gic = &gc->irq_contexts[i];
+               gic = kcalloc(1, sizeof(struct gdma_irq_context), GFP_KERNEL);
+               if (!gic) {
+                       err = -ENOMEM;
+                       goto free_irq;
+               }
                gic->handler = mana_gd_process_eq_events;
                INIT_LIST_HEAD(&gic->eq_list);
                spin_lock_init(&gic->lock);
@@ -1372,22 +1487,14 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev)
                irq = pci_irq_vector(pdev, i);
                if (irq < 0) {
                        err = irq;
-                       goto free_irq;
+                       goto free_current_gic;
                }
 
                if (!i) {
                        err = request_irq(irq, mana_gd_intr, 0, gic->name, gic);
                        if (err)
-                               goto free_irq;
-
-                       /* If number of IRQ is one extra than number of online 
CPUs,
-                        * then we need to assign IRQ0 (hwc irq) and IRQ1 to
-                        * same CPU.
-                        * Else we will use different CPUs for IRQ0 and IRQ1.
-                        * Also we are using cpumask_local_spread instead of
-                        * cpumask_first for the node, because the node can be
-                        * mem only.
-                        */
+                               goto free_current_gic;
+
                        if (start_irq_index) {
                                cpu = cpumask_local_spread(i, gc->numa_node);
                                irq_set_affinity_and_hint(irq, cpumask_of(cpu));
@@ -1399,36 +1506,104 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev)
                        err = request_irq(irqs[i - start_irq_index], 
mana_gd_intr, 0,
                                          gic->name, gic);
                        if (err)
-                               goto free_irq;
+                               goto free_current_gic;
                }
+
+               list_add_tail(&gic->gic_list, &gc->irq_contexts);
        }
 
-       err = irq_setup(irqs, (nvec - start_irq_index), gc->numa_node);
+       err = irq_setup(irqs, nvec - start_irq_index, gc->numa_node, 0);
        if (err)
                goto free_irq;
 
-       gc->max_num_msix = nvec;
-       gc->num_msix_usable = nvec;
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flags);
        cpus_read_unlock();
        kfree(irqs);
        return 0;
 
+free_current_gic:
+       kfree(gic);
 free_irq:
        for (j = i - 1; j >= 0; j--) {
                irq = pci_irq_vector(pdev, j);
-               gic = &gc->irq_contexts[j];
-
+               gic = list_last_entry(&gc->irq_contexts, struct 
gdma_irq_context, gic_list);
                irq_update_affinity_hint(irq, NULL);
                free_irq(irq, gic);
+               list_del(&gic->gic_list);
+               kfree(gic);
        }
-
-       kfree(gc->irq_contexts);
-       gc->irq_contexts = NULL;
-free_irq_array:
        kfree(irqs);
 free_irq_vector:
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flags);
        cpus_read_unlock();
-       pci_free_irq_vectors(pdev);
+       return err;
+}
+
+static int mana_gd_setup_hwc_irqs(struct pci_dev *pdev)
+{
+       struct gdma_context *gc = pci_get_drvdata(pdev);
+       unsigned int max_irqs, min_irqs;
+       int max_queues_per_port;
+       int nvec, err;
+
+       if (pci_msix_can_alloc_dyn(pdev)) {
+               max_irqs = 1;
+               min_irqs = 1;
+       } else {
+               max_queues_per_port = num_online_cpus();
+               if (max_queues_per_port > MANA_MAX_NUM_QUEUES)
+                       max_queues_per_port = MANA_MAX_NUM_QUEUES;
+               /* Need 1 interrupt for the Hardware communication Channel 
(HWC) */
+               max_irqs = max_queues_per_port + 1;
+               min_irqs = 2;
+       }
+
+       nvec = pci_alloc_irq_vectors(pdev, min_irqs, max_irqs, PCI_IRQ_MSIX);
+       if (nvec < 0)
+               return nvec;
+
+       err = mana_gd_setup_irqs(pdev, nvec);
+       if (err) {
+               pci_free_irq_vectors(pdev);
+               return err;
+       }
+
+       gc->num_msix_usable = nvec;
+       gc->max_num_msix = nvec;
+
+       return err;
+}
+
+static int mana_gd_setup_remaining_irqs(struct pci_dev *pdev)
+{
+       struct gdma_context *gc = pci_get_drvdata(pdev);
+       int max_irqs, i, err = 0;
+       struct msi_map irq_map;
+
+       if (!pci_msix_can_alloc_dyn(pdev))
+               /* remain irqs are already allocated with HWC IRQ */
+               return 0;
+
+       /* allocate only remaining IRQs*/
+       max_irqs = gc->num_msix_usable - 1;
+
+       for (i = 1; i <= max_irqs; i++) {
+               irq_map = pci_msix_alloc_irq_at(pdev, i, NULL);
+               if (!irq_map.virq) {
+                       err = irq_map.index;
+                       /* caller will handle cleaning up all allocated
+                        * irqs, after HWC is destroyed
+                        */
+                       return err;
+               }
+       }
+
+       err = mana_gd_setup_dyn_irqs(pdev, max_irqs);
+       if (err)
+               return err;
+
+       gc->max_num_msix = gc->max_num_msix + max_irqs;
+
        return err;
 }
 
@@ -1436,29 +1611,34 @@ static void mana_gd_remove_irqs(struct pci_dev *pdev)
 {
        struct gdma_context *gc = pci_get_drvdata(pdev);
        struct gdma_irq_context *gic;
-       int irq, i;
+       struct list_head *pos, *n;
+       unsigned long flags;
+       int irq, i = 0;
 
        if (gc->max_num_msix < 1)
                return;
 
-       for (i = 0; i < gc->max_num_msix; i++) {
+       spin_lock_irqsave(&gc->irq_ctxs_lock, flags);
+       list_for_each_safe(pos, n, &gc->irq_contexts) {
                irq = pci_irq_vector(pdev, i);
                if (irq < 0)
                        continue;
 
-               gic = &gc->irq_contexts[i];
+               gic = list_entry(pos, struct gdma_irq_context, gic_list);
 
                /* Need to clear the hint before free_irq */
                irq_update_affinity_hint(irq, NULL);
                free_irq(irq, gic);
+               list_del(pos);
+               kfree(gic);
+               i++;
        }
+       spin_unlock_irqrestore(&gc->irq_ctxs_lock, flags);
 
        pci_free_irq_vectors(pdev);
 
        gc->max_num_msix = 0;
        gc->num_msix_usable = 0;
-       kfree(gc->irq_contexts);
-       gc->irq_contexts = NULL;
 }
 
 static int mana_gd_setup(struct pci_dev *pdev)
@@ -1469,9 +1649,9 @@ static int mana_gd_setup(struct pci_dev *pdev)
        mana_gd_init_registers(pdev);
        mana_smc_init(&gc->shm_channel, gc->dev, gc->shm_base);
 
-       err = mana_gd_setup_irqs(pdev);
+       err = mana_gd_setup_hwc_irqs(pdev);
        if (err) {
-               dev_err(gc->dev, "Failed to setup IRQs: %d\n", err);
+               dev_err(gc->dev, "Failed to setup IRQs for HWC creation: %d\n", 
err);
                return err;
        }
 
@@ -1487,6 +1667,10 @@ static int mana_gd_setup(struct pci_dev *pdev)
        if (err)
                goto destroy_hwc;
 
+       err = mana_gd_setup_remaining_irqs(pdev);
+       if (err)
+               goto destroy_hwc;
+
        err = mana_gd_detect_devices(pdev);
        if (err)
                goto destroy_hwc;
@@ -1563,6 +1747,8 @@ static int mana_gd_probe(struct pci_dev *pdev, const 
struct pci_device_id *ent)
        gc->is_pf = mana_is_pf(pdev->device);
        gc->bar0_va = bar0_va;
        gc->dev = &pdev->dev;
+       INIT_LIST_HEAD(&gc->irq_contexts);
+       spin_lock_init(&gc->irq_ctxs_lock);
 
        if (gc->is_pf)
                gc->mana_pci_debugfs = debugfs_create_dir("0", 
mana_debugfs_root);
diff --git a/include/net/mana/gdma.h b/include/net/mana/gdma.h
index 228603bf03f2..eae38d7302fe 100644
--- a/include/net/mana/gdma.h
+++ b/include/net/mana/gdma.h
@@ -363,6 +363,7 @@ struct gdma_irq_context {
        spinlock_t lock;
        struct list_head eq_list;
        char name[MANA_IRQ_NAME_SZ];
+       struct list_head gic_list;
 };
 
 struct gdma_context {
@@ -373,7 +374,9 @@ struct gdma_context {
        unsigned int            max_num_queues;
        unsigned int            max_num_msix;
        unsigned int            num_msix_usable;
-       struct gdma_irq_context *irq_contexts;
+       struct list_head        irq_contexts;
+       /* Protect the irq_contexts list */
+       spinlock_t              irq_ctxs_lock;
 
        /* L2 MTU */
        u16 adapter_mtu;
-- 
2.34.1


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