[PATCH 09/29] cxlflash: Check for removal when processing interrupt

["Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>]

To avoid processing an interrupt while memory may be yanked, check for
while in the interrupt handler. Bail when removal is imminent.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
---
 drivers/scsi/cxlflash/common.h |  2 ++
 drivers/scsi/cxlflash/main.c   | 21 +++++++++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h
index 1abe4e0..03d2cc6 100644
--- a/drivers/scsi/cxlflash/common.h
+++ b/drivers/scsi/cxlflash/common.h
@@ -103,6 +103,8 @@ struct cxlflash_cfg {
 	enum cxlflash_lr_state lr_state;
 	int lr_port;
 
+	atomic_t remove_active;
+
 	struct cxl_afu *cxl_afu;
 
 	struct pci_pool *cxlflash_cmd_pool;
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 6e85c77..89ee648 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -892,6 +892,7 @@ static void cxlflash_remove(struct pci_dev *pdev)
 	spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags);
 
 	cfg->state = STATE_FAILTERM;
+	atomic_inc(&cfg->remove_active);
 	cxlflash_stop_term_user_contexts(cfg);
 
 	switch (cfg->init_state) {
@@ -1380,16 +1381,20 @@ static void afu_err_intr_init(struct afu *afu)
 static irqreturn_t cxlflash_sync_err_irq(int irq, void *data)
 {
 	struct afu *afu = (struct afu *)data;
+	struct cxlflash_cfg *cfg = afu->parent;
 	u64 reg;
 	u64 reg_unmasked;
 
+	if (atomic_read(&cfg->remove_active))
+		goto out;
+
 	reg = readq_be(&afu->host_map->intr_status);
 	reg_unmasked = (reg & SISL_ISTATUS_UNMASK);
 
 	if (reg_unmasked == 0UL) {
 		pr_err("%s: %llX: spurious interrupt, intr_status %016llX\n",
 		       __func__, (u64)afu, reg);
-		goto cxlflash_sync_err_irq_exit;
+		goto out;
 	}
 
 	pr_err("%s: %llX: unexpected interrupt, intr_status %016llX\n",
@@ -1397,7 +1402,7 @@ static irqreturn_t cxlflash_sync_err_irq(int irq, void *data)
 
 	writeq_be(reg_unmasked, &afu->host_map->intr_clear);
 
-cxlflash_sync_err_irq_exit:
+out:
 	pr_debug("%s: returning rc=%d\n", __func__, IRQ_HANDLED);
 	return IRQ_HANDLED;
 }
@@ -1412,6 +1417,7 @@ cxlflash_sync_err_irq_exit:
 static irqreturn_t cxlflash_rrq_irq(int irq, void *data)
 {
 	struct afu *afu = (struct afu *)data;
+	struct cxlflash_cfg *cfg = afu->parent;
 	struct afu_cmd *cmd;
 	bool toggle = afu->toggle;
 	u64 entry,
@@ -1421,8 +1427,10 @@ static irqreturn_t cxlflash_rrq_irq(int irq, void *data)
 
 	/* Process however many RRQ entries that are ready */
 	while (true) {
-		entry = *hrrq_curr;
+		if (atomic_read(&cfg->remove_active))
+			goto out;
 
+		entry = *hrrq_curr;
 		if ((entry & SISL_RESP_HANDLE_T_BIT) != toggle)
 			break;
 
@@ -1440,7 +1448,7 @@ static irqreturn_t cxlflash_rrq_irq(int irq, void *data)
 
 	afu->hrrq_curr = hrrq_curr;
 	afu->toggle = toggle;
-
+out:
 	return IRQ_HANDLED;
 }
 
@@ -1454,7 +1462,7 @@ static irqreturn_t cxlflash_rrq_irq(int irq, void *data)
 static irqreturn_t cxlflash_async_err_irq(int irq, void *data)
 {
 	struct afu *afu = (struct afu *)data;
-	struct cxlflash_cfg *cfg;
+	struct cxlflash_cfg *cfg = afu->parent;
 	u64 reg_unmasked;
 	const struct asyc_intr_info *info;
 	struct sisl_global_map *global = &afu->afu_map->global;
@@ -1462,7 +1470,8 @@ static irqreturn_t cxlflash_async_err_irq(int irq, void *data)
 	u8 port;
 	int i;
 
-	cfg = afu->parent;
+	if (atomic_read(&cfg->remove_active))
+		goto out;
 
 	reg = readq_be(&global->regs.aintr_status);
 	reg_unmasked = (reg & SISL_ASTATUS_UNMASK);
-- 
2.1.0