Merge v7.1.5linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 118 insertions, 33 deletions

diff --git a/drivers/pci/endpoint/functions/pci-epf-ntb.c b/drivers/pci/endpoint/functions/pci-epf-ntb.c
index 2bdcc35b652c..5314aca2188a 100644
--- a/drivers/pci/endpoint/functions/pci-epf-ntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-ntb.c
@@ -559,12 +559,15 @@ static int epf_ntb_configure_db(struct epf_ntb *ntb,
 	struct pci_epc *epc;
 	int ret;
 
-	if (db_count > MAX_DB_COUNT)
-		return -EINVAL;
-
 	ntb_epc = ntb->epc[type];
 	epc = ntb_epc->epc;
 
+	if (!db_count || db_count > MAX_DB_COUNT) {
+		dev_err(&epc->dev, "DB count %d out of range (1 - %d)\n",
+			db_count, MAX_DB_COUNT);
+		return -EINVAL;
+	}
+
 	if (msix)
 		ret = epf_ntb_configure_msix(ntb, type, db_count);
 	else
@@ -1278,7 +1281,6 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb,
 	u8 func_no, vfunc_no;
 	struct pci_epc *epc;
 	struct device *dev;
-	u32 db_count;
 	int ret;
 
 	ntb_epc = ntb->epc[type];
@@ -1296,17 +1298,16 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb,
 	func_no = ntb_epc->func_no;
 	vfunc_no = ntb_epc->vfunc_no;
 
-	db_count = ntb->db_count;
-	if (db_count > MAX_DB_COUNT) {
-		dev_err(dev, "DB count cannot be more than %d\n", MAX_DB_COUNT);
+	if (!ntb->db_count || ntb->db_count > MAX_DB_COUNT) {
+		dev_err(dev, "DB count %d out of range (1 - %d)\n",
+			ntb->db_count, MAX_DB_COUNT);
 		return -EINVAL;
 	}
 
-	ntb->db_count = db_count;
 	epc = ntb_epc->epc;
 
 	if (msi_capable) {
-		ret = pci_epc_set_msi(epc, func_no, vfunc_no, db_count);
+		ret = pci_epc_set_msi(epc, func_no, vfunc_no, ntb->db_count);
 		if (ret) {
 			dev_err(dev, "%s intf: MSI configuration failed\n",
 				pci_epc_interface_string(type));
@@ -1315,7 +1316,7 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb,
 	}
 
 	if (msix_capable) {
-		ret = pci_epc_set_msix(epc, func_no, vfunc_no, db_count,
+		ret = pci_epc_set_msix(epc, func_no, vfunc_no, ntb->db_count,
 				       ntb_epc->msix_bar,
 				       ntb_epc->msix_table_offset);
 		if (ret) {
diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index 2256c3062b1a..ff9db8f980af 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -37,6 +37,7 @@
  */
 
 #include <linux/atomic.h>
+#include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -69,6 +70,9 @@ static struct workqueue_struct *kpcintb_workqueue;
 #define MAX_DB_COUNT			32
 #define MAX_MW				4
 
+/* Limit per-work execution to avoid monopolizing kworker on doorbell storms. */
+#define VNTB_PEER_DB_WORK_BUDGET	5
+
 enum epf_ntb_bar {
 	BAR_CONFIG,
 	BAR_DB,
@@ -79,6 +83,12 @@ enum epf_ntb_bar {
 	VNTB_BAR_NUM,
 };
 
+enum epf_irq_slot {
+	EPF_IRQ_LINK = 0,
+	EPF_IRQ_RESERVED_DB, /* Historically skipped slot */
+	EPF_IRQ_DB_START,
+};
+
 /*
  * +--------------------------------------------------+ Base
  * |                                                  |
@@ -129,6 +139,8 @@ struct epf_ntb {
 	u32 spad_count;
 	u64 mws_size[MAX_MW];
 	atomic64_t db;
+	atomic64_t peer_db_pending;
+	struct work_struct peer_db_work;
 	u32 vbus_number;
 	u16 vntb_pid;
 	u16 vntb_vid;
@@ -261,10 +273,11 @@ static void epf_ntb_cmd_handler(struct work_struct *work)
 
 	ntb = container_of(work, struct epf_ntb, cmd_handler.work);
 
-	for (i = 1; i < ntb->db_count && !ntb->msi_doorbell; i++) {
+	for (i = EPF_IRQ_DB_START; i < ntb->db_count && !ntb->msi_doorbell;
+	     i++) {
 		if (ntb->epf_db[i]) {
-			atomic64_or(1 << (i - 1), &ntb->db);
-			ntb_db_event(&ntb->ntb, i);
+			atomic64_or(1 << (i - EPF_IRQ_DB_START), &ntb->db);
+			ntb_db_event(&ntb->ntb, i - EPF_IRQ_DB_START);
 			ntb->epf_db[i] = 0;
 		}
 	}
@@ -330,10 +343,10 @@ static irqreturn_t epf_ntb_doorbell_handler(int irq, void *data)
 	struct epf_ntb *ntb = data;
 	int i;
 
-	for (i = 1; i < ntb->db_count; i++)
+	for (i = EPF_IRQ_DB_START; i < ntb->db_count; i++)
 		if (irq == ntb->epf->db_msg[i].virq) {
-			atomic64_or(1 << (i - 1), &ntb->db);
-			ntb_db_event(&ntb->ntb, i);
+			atomic64_or(1 << (i - EPF_IRQ_DB_START), &ntb->db);
+			ntb_db_event(&ntb->ntb, i - EPF_IRQ_DB_START);
 		}
 
 	return IRQ_HANDLED;
@@ -483,7 +496,6 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)
 {
 	const struct pci_epc_features *epc_features;
 	struct device *dev;
-	u32 db_count;
 	int ret;
 
 	dev = &ntb->epf->dev;
@@ -495,14 +507,12 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)
 		return -EINVAL;
 	}
 
-	db_count = ntb->db_count;
-	if (db_count > MAX_DB_COUNT) {
-		dev_err(dev, "DB count cannot be more than %d\n", MAX_DB_COUNT);
+	if (!ntb->db_count || ntb->db_count > MAX_DB_COUNT) {
+		dev_err(dev, "DB count %d out of range (1 - %d)\n",
+			ntb->db_count, MAX_DB_COUNT);
 		return -EINVAL;
 	}
 
-	ntb->db_count = db_count;
-
 	if (epc_features->msi_capable) {
 		ret = pci_epc_set_msi(ntb->epf->epc,
 				      ntb->epf->func_no,
@@ -920,6 +930,9 @@ static int epf_ntb_epc_init(struct epf_ntb *ntb)
 	INIT_DELAYED_WORK(&ntb->cmd_handler, epf_ntb_cmd_handler);
 	queue_work(kpcintb_workqueue, &ntb->cmd_handler.work);
 
+	atomic64_set(&ntb->peer_db_pending, 0);
+	enable_work(&ntb->peer_db_work);
+
 	return 0;
 
 err_write_header:
@@ -943,6 +956,8 @@ err_config_interrupt:
 static void epf_ntb_epc_cleanup(struct epf_ntb *ntb)
 {
 	disable_delayed_work_sync(&ntb->cmd_handler);
+	disable_work_sync(&ntb->peer_db_work);
+	atomic64_set(&ntb->peer_db_pending, 0);
 	epf_ntb_mw_bar_clear(ntb, ntb->num_mws);
 	epf_ntb_db_bar_clear(ntb);
 	epf_ntb_config_sspad_bar_clear(ntb);
@@ -1253,7 +1268,10 @@ static int vntb_epf_peer_mw_count(struct ntb_dev *ntb)
 
 static u64 vntb_epf_db_valid_mask(struct ntb_dev *ntb)
 {
-	return BIT_ULL(ntb_ndev(ntb)->db_count) - 1;
+	if (ntb_ndev(ntb)->db_count < EPF_IRQ_DB_START)
+		return 0;
+
+	return BIT_ULL(ntb_ndev(ntb)->db_count - EPF_IRQ_DB_START) - 1;
 }
 
 static int vntb_epf_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
@@ -1357,22 +1375,84 @@ static int vntb_epf_peer_spad_write(struct ntb_dev *ndev, int pidx, int idx, u32
 	return 0;
 }
 
-static int vntb_epf_peer_db_set(struct ntb_dev *ndev, u64 db_bits)
+static void vntb_epf_peer_db_work(struct work_struct *work)
 {
-	u32 interrupt_num = ffs(db_bits) + 1;
-	struct epf_ntb *ntb = ntb_ndev(ndev);
+	struct epf_ntb *ntb = container_of(work, struct epf_ntb, peer_db_work);
+	struct pci_epf *epf = ntb->epf;
+	unsigned int budget = VNTB_PEER_DB_WORK_BUDGET;
 	u8 func_no, vfunc_no;
+	unsigned int db_bit;
+	u32 interrupt_num;
+	u64 db_bits;
 	int ret;
 
-	func_no = ntb->epf->func_no;
-	vfunc_no = ntb->epf->vfunc_no;
+	if (!epf || !epf->epc)
+		return;
+
+	func_no = epf->func_no;
+	vfunc_no = epf->vfunc_no;
+
+	/*
+	 * Drain doorbells from peer_db_pending in snapshots (atomic64_xchg()).
+	 * Limit the number of snapshots handled per run so we don't monopolize
+	 * the workqueue under a doorbell storm.
+	 */
+	while (budget--) {
+		db_bits = atomic64_xchg(&ntb->peer_db_pending, 0);
+		if (!db_bits)
+			return;
+
+		while (db_bits) {
+			/*
+			 * pci_epc_raise_irq() for MSI expects a 1-based
+			 * interrupt number. The first usable doorbell starts
+			 * at EPF_IRQ_DB_START in the legacy slot layout.
+			 *
+			 * Legacy mapping (kept for compatibility):
+			 *
+			 *   MSI #1 : link event (reserved)
+			 *   MSI #2 : unused (historical offset)
+			 *   MSI #3 : doorbell bit 0 (DB#0)
+			 *   MSI #4 : doorbell bit 1 (DB#1)
+			 *   ...
+			 *
+			 * Do not change this mapping to avoid breaking
+			 * interoperability with older peers.
+			 */
+			db_bit = __ffs64(db_bits);
+			interrupt_num = db_bit + EPF_IRQ_DB_START + 1;
+			db_bits &= ~BIT_ULL(db_bit);
+
+			ret = pci_epc_raise_irq(epf->epc, func_no, vfunc_no,
+						PCI_IRQ_MSI, interrupt_num);
+			if (ret)
+				dev_err(&ntb->ntb.dev,
+					"Failed to raise IRQ for interrupt_num %u: %d\n",
+					interrupt_num, ret);
+		}
+	}
 
-	ret = pci_epc_raise_irq(ntb->epf->epc, func_no, vfunc_no,
-				PCI_IRQ_MSI, interrupt_num + 1);
-	if (ret)
-		dev_err(&ntb->ntb.dev, "Failed to raise IRQ\n");
+	if (atomic64_read(&ntb->peer_db_pending))
+		queue_work(kpcintb_workqueue, &ntb->peer_db_work);
+}
 
-	return ret;
+static int vntb_epf_peer_db_set(struct ntb_dev *ndev, u64 db_bits)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+
+	db_bits &= vntb_epf_db_valid_mask(ndev);
+	if (!db_bits)
+		return 0;
+
+	/*
+	 * .peer_db_set() may be called from atomic context. pci_epc_raise_irq()
+	 * can sleep (it takes epc->lock), so defer MSI raising to process
+	 * context. Doorbell requests are coalesced in peer_db_pending.
+	 */
+	atomic64_or(db_bits, &ntb->peer_db_pending);
+	queue_work(kpcintb_workqueue, &ntb->peer_db_work);
+
+	return 0;
 }
 
 static u64 vntb_epf_db_read(struct ntb_dev *ndev)
@@ -1619,6 +1699,10 @@ static int epf_ntb_probe(struct pci_epf *epf,
 	ntb->epf = epf;
 	ntb->vbus_number = 0xff;
 
+	INIT_WORK(&ntb->peer_db_work, vntb_epf_peer_db_work);
+	disable_work(&ntb->peer_db_work);
+	atomic64_set(&ntb->peer_db_pending, 0);
+
 	/* Initially, no bar is assigned */
 	for (i = 0; i < VNTB_BAR_NUM; i++)
 		ntb->epf_ntb_bar[i] = NO_BAR;