gdrom: convert to blk-mq

Ditch the deffered list, lock, and workqueue handling. Just mark the
set as being blocking, so we are invoked from a workqueue already.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 79 insertions, 95 deletions

diff --git a/drivers/cdrom/gdrom.c b/drivers/cdrom/gdrom.c
index ae3a7537cf0f..757e85b81879 100644
--- a/drivers/cdrom/gdrom.c
+++ b/drivers/cdrom/gdrom.c
@@ -31,12 +31,11 @@
 #include <linux/cdrom.h>
 #include <linux/genhd.h>
 #include <linux/bio.h>
-#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
 #include <linux/wait.h>
-#include <linux/workqueue.h>
 #include <linux/platform_device.h>
 #include <scsi/scsi.h>
 #include <asm/io.h>
@@ -102,11 +101,6 @@ static int gdrom_major;
 static DECLARE_WAIT_QUEUE_HEAD(command_queue);
 static DECLARE_WAIT_QUEUE_HEAD(request_queue);
 
-static DEFINE_SPINLOCK(gdrom_lock);
-static void gdrom_readdisk_dma(struct work_struct *work);
-static DECLARE_WORK(work, gdrom_readdisk_dma);
-static LIST_HEAD(gdrom_deferred);
-
 struct gdromtoc {
         unsigned int entry[99];
         unsigned int first, last;
@@ -122,6 +116,7 @@ static struct gdrom_unit {
         char disk_type;
         struct gdromtoc *toc;
         struct request_queue *gdrom_rq;
+        struct blk_mq_tag_set tag_set;
 } gd;
 
 struct gdrom_id {
@@ -584,103 +579,83 @@ static int gdrom_set_interrupt_handlers(void)
  * 9 -> sectors >> 8
  * 10 -> sectors
  */
-static void gdrom_readdisk_dma(struct work_struct *work)
+static blk_status_t gdrom_readdisk_dma(struct request *req)
 {
         int block, block_cnt;
         blk_status_t err;
         struct packet_command *read_command;
-        struct list_head *elem, *next;
-        struct request *req;
         unsigned long timeout;
 
-        if (list_empty(&gdrom_deferred))
-                return;
         read_command = kzalloc(sizeof(struct packet_command), GFP_KERNEL);
         if (!read_command)
-                return; /* get more memory later? */
+                return BLK_STS_RESOURCE;
+
         read_command->cmd[0] = 0x30;
         read_command->cmd[1] = 0x20;
-        spin_lock(&gdrom_lock);
-        list_for_each_safe(elem, next, &gdrom_deferred) {
-                req = list_entry(elem, struct request, queuelist);
-                spin_unlock(&gdrom_lock);
-                block = blk_rq_pos(req)/GD_TO_BLK + GD_SESSION_OFFSET;
-                block_cnt = blk_rq_sectors(req)/GD_TO_BLK;
-                __raw_writel(virt_to_phys(bio_data(req->bio)), GDROM_DMA_STARTADDR_REG);
-                __raw_writel(block_cnt * GDROM_HARD_SECTOR, GDROM_DMA_LENGTH_REG);
-                __raw_writel(1, GDROM_DMA_DIRECTION_REG);
-                __raw_writel(1, GDROM_DMA_ENABLE_REG);
-                read_command->cmd[2] = (block >> 16) & 0xFF;
-                read_command->cmd[3] = (block >> 8) & 0xFF;
-                read_command->cmd[4] = block & 0xFF;
-                read_command->cmd[8] = (block_cnt >> 16) & 0xFF;
-                read_command->cmd[9] = (block_cnt >> 8) & 0xFF;
-                read_command->cmd[10] = block_cnt & 0xFF;
-                /* set for DMA */
-                __raw_writeb(1, GDROM_ERROR_REG);
-                /* other registers */
-                __raw_writeb(0, GDROM_SECNUM_REG);
-                __raw_writeb(0, GDROM_BCL_REG);
-                __raw_writeb(0, GDROM_BCH_REG);
-                __raw_writeb(0, GDROM_DSEL_REG);
-                __raw_writeb(0, GDROM_INTSEC_REG);
-                /* Wait for registers to reset after any previous activity */
-                timeout = jiffies + HZ / 2;
-                while (gdrom_is_busy() && time_before(jiffies, timeout))
-                        cpu_relax();
-                __raw_writeb(GDROM_COM_PACKET, GDROM_STATUSCOMMAND_REG);
-                timeout = jiffies + HZ / 2;
-                /* Wait for packet command to finish */
-                while (gdrom_is_busy() && time_before(jiffies, timeout))
-                        cpu_relax();
-                gd.pending = 1;
-                gd.transfer = 1;
-                outsw(GDROM_DATA_REG, &read_command->cmd, 6);
-                timeout = jiffies + HZ / 2;
-                /* Wait for any pending DMA to finish */
-                while (__raw_readb(GDROM_DMA_STATUS_REG) &&
-                        time_before(jiffies, timeout))
-                        cpu_relax();
-                /* start transfer */
-                __raw_writeb(1, GDROM_DMA_STATUS_REG);
-                wait_event_interruptible_timeout(request_queue,
-                        gd.transfer == 0, GDROM_DEFAULT_TIMEOUT);
-                err = gd.transfer ? BLK_STS_IOERR : BLK_STS_OK;
-                gd.transfer = 0;
-                gd.pending = 0;
-                /* now seek to take the request spinlock
-                * before handling ending the request */
-                spin_lock(&gdrom_lock);
-                list_del_init(&req->queuelist);
-                __blk_end_request_all(req, err);
-        }
-        spin_unlock(&gdrom_lock);
+        block = blk_rq_pos(req)/GD_TO_BLK + GD_SESSION_OFFSET;
+        block_cnt = blk_rq_sectors(req)/GD_TO_BLK;
+        __raw_writel(virt_to_phys(bio_data(req->bio)), GDROM_DMA_STARTADDR_REG);
+        __raw_writel(block_cnt * GDROM_HARD_SECTOR, GDROM_DMA_LENGTH_REG);
+        __raw_writel(1, GDROM_DMA_DIRECTION_REG);
+        __raw_writel(1, GDROM_DMA_ENABLE_REG);
+        read_command->cmd[2] = (block >> 16) & 0xFF;
+        read_command->cmd[3] = (block >> 8) & 0xFF;
+        read_command->cmd[4] = block & 0xFF;
+        read_command->cmd[8] = (block_cnt >> 16) & 0xFF;
+        read_command->cmd[9] = (block_cnt >> 8) & 0xFF;
+        read_command->cmd[10] = block_cnt & 0xFF;
+        /* set for DMA */
+        __raw_writeb(1, GDROM_ERROR_REG);
+        /* other registers */
+        __raw_writeb(0, GDROM_SECNUM_REG);
+        __raw_writeb(0, GDROM_BCL_REG);
+        __raw_writeb(0, GDROM_BCH_REG);
+        __raw_writeb(0, GDROM_DSEL_REG);
+        __raw_writeb(0, GDROM_INTSEC_REG);
+        /* Wait for registers to reset after any previous activity */
+        timeout = jiffies + HZ / 2;
+        while (gdrom_is_busy() && time_before(jiffies, timeout))
+                cpu_relax();
+        __raw_writeb(GDROM_COM_PACKET, GDROM_STATUSCOMMAND_REG);
+        timeout = jiffies + HZ / 2;
+        /* Wait for packet command to finish */
+        while (gdrom_is_busy() && time_before(jiffies, timeout))
+                cpu_relax();
+        gd.pending = 1;
+        gd.transfer = 1;
+        outsw(GDROM_DATA_REG, &read_command->cmd, 6);
+        timeout = jiffies + HZ / 2;
+        /* Wait for any pending DMA to finish */
+        while (__raw_readb(GDROM_DMA_STATUS_REG) &&
+                time_before(jiffies, timeout))
+                cpu_relax();
+        /* start transfer */
+        __raw_writeb(1, GDROM_DMA_STATUS_REG);
+        wait_event_interruptible_timeout(request_queue,
+                gd.transfer == 0, GDROM_DEFAULT_TIMEOUT);
+        err = gd.transfer ? BLK_STS_IOERR : BLK_STS_OK;
+        gd.transfer = 0;
+        gd.pending = 0;
+
+        blk_mq_end_request(req, err);
         kfree(read_command);
+        return BLK_STS_OK;
 }
 
-static void gdrom_request(struct request_queue *rq)
-{
-        struct request *req;
-
-        while ((req = blk_fetch_request(rq)) != NULL) {
-                switch (req_op(req)) {
-                case REQ_OP_READ:
-                        /*
-                         * Add to list of deferred work and then schedule
-                         * workqueue.
-                         */
-                        list_add_tail(&req->queuelist, &gdrom_deferred);
-                        schedule_work(&work);
-                        break;
-                case REQ_OP_WRITE:
-                        pr_notice("Read only device - write request ignored\n");
-                        __blk_end_request_all(req, BLK_STS_IOERR);
-                        break;
-                default:
-                        printk(KERN_DEBUG "gdrom: Non-fs request ignored\n");
-                        __blk_end_request_all(req, BLK_STS_IOERR);
-                        break;
-                }
+static blk_status_t gdrom_queue_rq(struct blk_mq_hw_ctx *hctx,
+                                   const struct blk_mq_queue_data *bd)
+{
+        blk_mq_start_request(bd->rq);
+
+        switch (req_op(bd->rq)) {
+        case REQ_OP_READ:
+                return gdrom_readdisk_dma(bd->rq);
+        case REQ_OP_WRITE:
+                pr_notice("Read only device - write request ignored\n");
+                return BLK_STS_IOERR;
+        default:
+                printk(KERN_DEBUG "gdrom: Non-fs request ignored\n");
+                return BLK_STS_IOERR;
         }
 }
 
@@ -768,6 +743,10 @@ static int probe_gdrom_setupqueue(void)
         return gdrom_init_dma_mode();
 }
 
+static const struct blk_mq_ops gdrom_mq_ops = {
+        .queue_rq       = gdrom_queue_rq,
+};
+
 /*
  * register this as a block device and as compliant with the
  * universal CD Rom driver interface
@@ -811,11 +790,15 @@ static int probe_gdrom(struct platform_device *devptr)
         err = gdrom_set_interrupt_handlers();
         if (err)
                 goto probe_fail_cmdirq_register;
-        gd.gdrom_rq = blk_init_queue(gdrom_request, &gdrom_lock);
-        if (!gd.gdrom_rq) {
-                err = -ENOMEM;
+
+        gd.gdrom_rq = blk_mq_init_sq_queue(&gd.tag_set, &gdrom_mq_ops, 1,
+                                BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
+        if (IS_ERR(gd.gdrom_rq)) {
+                rc = PTR_ERR(gd.gdrom_rq);
+                gd.gdrom_rq = NULL;
                 goto probe_fail_requestq;
         }
+
         blk_queue_bounce_limit(gd.gdrom_rq, BLK_BOUNCE_HIGH);
 
         err = probe_gdrom_setupqueue();
@@ -832,6 +815,7 @@ static int probe_gdrom(struct platform_device *devptr)
 
 probe_fail_toc:
         blk_cleanup_queue(gd.gdrom_rq);
+        blk_mq_free_tag_set(&gd.tag_set);
 probe_fail_requestq:
         free_irq(HW_EVENT_GDROM_DMA, &gd);
         free_irq(HW_EVENT_GDROM_CMD, &gd);
@@ -849,8 +833,8 @@ probe_fail_no_mem:
 
 static int remove_gdrom(struct platform_device *devptr)
 {
-        flush_work(&work);
         blk_cleanup_queue(gd.gdrom_rq);
+        blk_mq_free_tag_set(&gd.tag_set);
         free_irq(HW_EVENT_GDROM_CMD, &gd);
         free_irq(HW_EVENT_GDROM_DMA, &gd);
         del_gendisk(gd.disk);