mmc: omap: convert to per instance workqueue

Currently, a global mmc_omap_wq is created for all instances of omap
hosts, which can lead to races and doesn't lend itself to unload the
module cleanly.  Instead, create per instance workqueue and remove
 the common workqueue.

Signed-off-by: Venkatraman S <[email protected]>
Acked-by: Balaji T K <[email protected]>
Signed-off-by: Chris Ball <[email protected]>

Author: Venkatraman S

drivers/mmc/host/omap.c

@@ -169,11 +169,11 @@ struct mmc_omap_host {
 	struct timer_list       clk_timer;
 	spinlock_t		clk_lock;     /* for changing enabled state */
 	unsigned int            fclk_enabled:1;
+	struct workqueue_struct *mmc_omap_wq;
 
 	struct omap_mmc_platform_data *pdata;
 };
 
-static struct workqueue_struct *mmc_omap_wq;
 
 static void mmc_omap_fclk_offdelay(struct mmc_omap_slot *slot)
 {
@@ -291,7 +291,7 @@ static void mmc_omap_release_slot(struct mmc_omap_slot *slot, int clk_enabled)
 		host->next_slot = new_slot;
 		host->mmc = new_slot->mmc;
 		spin_unlock_irqrestore(&host->slot_lock, flags);
-		queue_work(mmc_omap_wq, &host->slot_release_work);
+		queue_work(host->mmc_omap_wq, &host->slot_release_work);
 		return;
 	}
 
@@ -459,7 +459,7 @@ mmc_omap_xfer_done(struct mmc_omap_host *host, struct mmc_data *data)
 	}
 
 	host->stop_data = data;
-	queue_work(mmc_omap_wq, &host->send_stop_work);
+	queue_work(host->mmc_omap_wq, &host->send_stop_work);
 }
 
 static void
@@ -639,7 +639,7 @@ mmc_omap_cmd_timer(unsigned long data)
 		OMAP_MMC_WRITE(host, IE, 0);
 		disable_irq(host->irq);
 		host->abort = 1;
-		queue_work(mmc_omap_wq, &host->cmd_abort_work);
+		queue_work(host->mmc_omap_wq, &host->cmd_abort_work);
 	}
 	spin_unlock_irqrestore(&host->slot_lock, flags);
 }
@@ -828,7 +828,7 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
 		host->abort = 1;
 		OMAP_MMC_WRITE(host, IE, 0);
 		disable_irq_nosync(host->irq);
-		queue_work(mmc_omap_wq, &host->cmd_abort_work);
+		queue_work(host->mmc_omap_wq, &host->cmd_abort_work);
 		return IRQ_HANDLED;
 	}
 
@@ -1389,7 +1389,7 @@ static void mmc_omap_remove_slot(struct mmc_omap_slot *slot)
 
 	tasklet_kill(&slot->cover_tasklet);
 	del_timer_sync(&slot->cover_timer);
-	flush_workqueue(mmc_omap_wq);
+	flush_workqueue(slot->host->mmc_omap_wq);
 
 	mmc_remove_host(mmc);
 	mmc_free_host(mmc);
@@ -1497,6 +1497,10 @@ static int __init mmc_omap_probe(struct platform_device *pdev)
 
 	host->reg_shift = (cpu_is_omap7xx() ? 1 : 2);
 
+	host->mmc_omap_wq = alloc_workqueue("mmc_omap", 0, 0);
+	if (!host->mmc_omap_wq)
+		goto err_plat_cleanup;
+
 	return 0;
 
 err_plat_cleanup:
@@ -1542,6 +1546,7 @@ static int mmc_omap_remove(struct platform_device *pdev)
 	iounmap(host->virt_base);
 	release_mem_region(pdev->resource[0].start,
 			   pdev->resource[0].end - pdev->resource[0].start + 1);
+	destroy_workqueue(host->mmc_omap_wq);
 
 	kfree(host);
 
@@ -1610,22 +1615,12 @@ static struct platform_driver mmc_omap_driver = {
 
 static int __init mmc_omap_init(void)
 {
-	int ret;
-
-	mmc_omap_wq = alloc_workqueue("mmc_omap", 0, 0);
-	if (!mmc_omap_wq)
-		return -ENOMEM;
-
-	ret = platform_driver_probe(&mmc_omap_driver, mmc_omap_probe);
-	if (ret)
-		destroy_workqueue(mmc_omap_wq);
-	return ret;
+	return platform_driver_probe(&mmc_omap_driver, mmc_omap_probe);
 }
 
 static void __exit mmc_omap_exit(void)
 {
 	platform_driver_unregister(&mmc_omap_driver);
-	destroy_workqueue(mmc_omap_wq);
 }
 
 module_init(mmc_omap_init);