ice: track interrupt vectors with xarray

Replace custom interrupt tracker with generic xarray data structure.
Remove all code responsible for searching for a new entry with xa_alloc,
which always tries to allocate at the lowes possible index. As a result
driver is always using a contiguous region of the MSIX vector table.

New tracker keeps ice_irq_entry entries in xarray as opaque for the rest
of the driver hiding the entry details from the caller.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Piotr Raczynski <piotr.raczynski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice.h

@@ -104,7 +104,6 @@
 #define ICE_Q_WAIT_RETRY_LIMIT	10
 #define ICE_Q_WAIT_MAX_RETRY	(5 * ICE_Q_WAIT_RETRY_LIMIT)
 #define ICE_MAX_LG_RSS_QS	256
-#define ICE_RES_VALID_BIT	0x8000
 #define ICE_INVAL_Q_INDEX	0xffff
 
 #define ICE_MAX_RXQS_PER_TC		256	/* Used when setting VSI context per TC Rx queues */
@@ -242,12 +241,6 @@ struct ice_tc_cfg {
 	struct ice_tc_info tc_info[ICE_MAX_TRAFFIC_CLASS];
 };
 
-struct ice_res_tracker {
-	u16 num_entries;
-	u16 end;
-	u16 list[];
-};
-
 struct ice_qs_cfg {
 	struct mutex *qs_mutex;  /* will be assigned to &pf->avail_q_mutex */
 	unsigned long *pf_map;
@@ -536,7 +529,7 @@ struct ice_pf {
 
 	/* OS reserved IRQ details */
 	struct msix_entry *msix_entries;
-	struct ice_res_tracker *irq_tracker;
+	struct ice_irq_tracker irq_tracker;
 	/* First MSIX vector used by SR-IOV VFs. Calculated by subtracting the
 	 * number of MSIX vectors needed for all SR-IOV VFs from the number of
 	 * MSIX vectors allowed on this PF.

drivers/net/ethernet/intel/ice/ice_irq.c

@@ -5,6 +5,75 @@
 #include "ice_lib.h"
 #include "ice_irq.h"
 
+/**
+ * ice_init_irq_tracker - initialize interrupt tracker
+ * @pf: board private structure
+ * @max_vectors: maximum number of vectors that tracker can hold
+ */
+static void
+ice_init_irq_tracker(struct ice_pf *pf, unsigned int max_vectors)
+{
+	pf->irq_tracker.num_entries = max_vectors;
+	xa_init_flags(&pf->irq_tracker.entries, XA_FLAGS_ALLOC);
+}
+
+/**
+ * ice_deinit_irq_tracker - free xarray tracker
+ * @pf: board private structure
+ */
+static void ice_deinit_irq_tracker(struct ice_pf *pf)
+{
+	xa_destroy(&pf->irq_tracker.entries);
+}
+
+/**
+ * ice_free_irq_res - free a block of resources
+ * @pf: board private structure
+ * @index: starting index previously returned by ice_get_res
+ */
+static void ice_free_irq_res(struct ice_pf *pf, u16 index)
+{
+	struct ice_irq_entry *entry;
+
+	entry = xa_erase(&pf->irq_tracker.entries, index);
+	kfree(entry);
+}
+
+/**
+ * ice_get_irq_res - get an interrupt resource
+ * @pf: board private structure
+ *
+ * Allocate new irq entry in the free slot of the tracker. Since xarray
+ * is used, always allocate new entry at the lowest possible index. Set
+ * proper allocation limit for maximum tracker entries.
+ *
+ * Returns allocated irq entry or NULL on failure.
+ */
+static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf)
+{
+	struct xa_limit limit = { .max = pf->irq_tracker.num_entries,
+				  .min = 0 };
+	struct ice_irq_entry *entry;
+	unsigned int index;
+	int ret;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return NULL;
+
+	ret = xa_alloc(&pf->irq_tracker.entries, &index, entry, limit,
+		       GFP_KERNEL);
+
+	if (ret) {
+		kfree(entry);
+		entry = NULL;
+	} else {
+		entry->index = index;
+	}
+
+	return entry;
+}
+
 /**
  * ice_reduce_msix_usage - Reduce usage of MSI-X vectors
  * @pf: board private structure
@@ -163,11 +232,7 @@ static int ice_ena_msix_range(struct ice_pf *pf)
 void ice_clear_interrupt_scheme(struct ice_pf *pf)
 {
 	pci_free_irq_vectors(pf->pdev);
-
-	if (pf->irq_tracker) {
-		devm_kfree(ice_pf_to_dev(pf), pf->irq_tracker);
-		pf->irq_tracker = NULL;
-	}
+	ice_deinit_irq_tracker(pf);
 }
 
 /**
@@ -183,19 +248,7 @@ int ice_init_interrupt_scheme(struct ice_pf *pf)
 	if (vectors < 0)
 		return vectors;
 
-	/* set up vector assignment tracking */
-	pf->irq_tracker = devm_kzalloc(ice_pf_to_dev(pf),
-				       struct_size(pf->irq_tracker, list,
-						   vectors),
-				       GFP_KERNEL);
-	if (!pf->irq_tracker) {
-		pci_free_irq_vectors(pf->pdev);
-		return -ENOMEM;
-	}
-
-	/* populate SW interrupts pool with number of OS granted IRQs. */
-	pf->irq_tracker->num_entries = (u16)vectors;
-	pf->irq_tracker->end = pf->irq_tracker->num_entries;
+	ice_init_irq_tracker(pf, vectors);
 
 	return 0;
 }
@@ -221,13 +274,13 @@ int ice_init_interrupt_scheme(struct ice_pf *pf)
 struct msi_map ice_alloc_irq(struct ice_pf *pf)
 {
 	struct msi_map map = { .index = -ENOENT };
-	int entry;
+	struct ice_irq_entry *entry;
 
-	entry = ice_get_res(pf, pf->irq_tracker);
-	if (entry < 0)
+	entry = ice_get_irq_res(pf);
+	if (!entry)
 		return map;
 
-	map.index = entry;
+	map.index = entry->index;
 	map.virq = pci_irq_vector(pf->pdev, map.index);
 
 	return map;
@@ -238,9 +291,9 @@ struct msi_map ice_alloc_irq(struct ice_pf *pf)
  * @pf: board private structure
  * @map: map with interrupt details
  *
- * Remove allocated interrupt from the interrupt tracker
+ * Remove allocated interrupt from the interrupt tracker.
  */
 void ice_free_irq(struct ice_pf *pf, struct msi_map map)
 {
-	ice_free_res(pf->irq_tracker, map.index);
+	ice_free_irq_res(pf, map.index);
 }

drivers/net/ethernet/intel/ice/ice_irq.h

@@ -4,6 +4,15 @@
 #ifndef _ICE_IRQ_H_
 #define _ICE_IRQ_H_
 
+struct ice_irq_entry {
+	unsigned int index;
+};
+
+struct ice_irq_tracker {
+	struct xarray entries;
+	u16 num_entries;	/* total vectors available */
+};
+
 int ice_init_interrupt_scheme(struct ice_pf *pf);
 void ice_clear_interrupt_scheme(struct ice_pf *pf);
 

drivers/net/ethernet/intel/ice/ice_lib.c

@@ -1370,51 +1370,6 @@ static int ice_vsi_init(struct ice_vsi *vsi, u32 vsi_flags)
 	return ret;
 }
 
-/**
- * ice_free_res - free a block of resources
- * @res: pointer to the resource
- * @index: starting index previously returned by ice_get_res
- *
- * Returns number of resources freed
- */
-int ice_free_res(struct ice_res_tracker *res, u16 index)
-{
-	if (!res || index >= res->end)
-		return -EINVAL;
-
-	res->list[index] = 0;
-
-	return 0;
-}
-
-/**
- * ice_get_res - get a resource from the tracker
- * @pf: board private structure
- * @res: pointer to the resource
- *
- * Returns the item index, or negative for error
- */
-int
-ice_get_res(struct ice_pf *pf, struct ice_res_tracker *res)
-{
-	u16 i;
-
-	if (!res || !pf)
-		return -EINVAL;
-
-	/* skip already allocated entries */
-	for (i = 0; i < res->end; i++)
-		if (!(res->list[i] & ICE_RES_VALID_BIT))
-			break;
-
-	if (i < res->end) {
-		res->list[i] = ICE_RES_VALID_BIT;
-		return i;
-	} else {
-		return -ENOMEM;
-	}
-}
-
 /**
  * ice_vsi_clear_rings - Deallocates the Tx and Rx rings for VSI
  * @vsi: the VSI having rings deallocated

drivers/net/ethernet/intel/ice/ice_lib.h

@@ -104,11 +104,6 @@ int ice_ena_vsi(struct ice_vsi *vsi, bool locked);
 void ice_vsi_decfg(struct ice_vsi *vsi);
 void ice_dis_vsi(struct ice_vsi *vsi, bool locked);
 
-int ice_free_res(struct ice_res_tracker *res, u16 index);
-
-int
-ice_get_res(struct ice_pf *pf, struct ice_res_tracker *res);
-
 int ice_vsi_rebuild(struct ice_vsi *vsi, u32 vsi_flags);
 int ice_vsi_cfg(struct ice_vsi *vsi, struct ice_vsi_cfg_params *params);
 

drivers/net/ethernet/intel/ice/ice_sriov.c

@@ -418,7 +418,7 @@ int ice_calc_vf_reg_idx(struct ice_vf *vf, struct ice_q_vector *q_vector)
 static int ice_sriov_set_msix_res(struct ice_pf *pf, u16 num_msix_needed)
 {
 	u16 total_vectors = pf->hw.func_caps.common_cap.num_msix_vectors;
-	int vectors_used = pf->irq_tracker->num_entries;
+	int vectors_used = pf->irq_tracker.num_entries;
 	int sriov_base_vector;
 
 	sriov_base_vector = total_vectors - num_msix_needed;
@@ -470,7 +470,7 @@ static int ice_set_per_vf_res(struct ice_pf *pf, u16 num_vfs)
 
 	/* determine MSI-X resources per VF */
 	msix_avail_for_sriov = pf->hw.func_caps.common_cap.num_msix_vectors -
-		pf->irq_tracker->num_entries;
+		pf->irq_tracker.num_entries;
 	msix_avail_per_vf = msix_avail_for_sriov / num_vfs;
 	if (msix_avail_per_vf >= ICE_NUM_VF_MSIX_MED) {
 		num_msix_per_vf = ICE_NUM_VF_MSIX_MED;