[PATCH 10/17] gdrom: convert to blk-mq

Jens Axboe
2018-10-11T16:59:02Z

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>
---
drivers/cdrom/gdrom.c | 182 ++++++++++++++++++++----------------------
1 file changed, 87 insertions(+), 95 deletions(-)

diff --git a/drivers/cdrom/gdrom.c b/drivers/cdrom/gdrom.c
index ae3a7537cf0f..41b57d9c4424 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 +790,23 @@ 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.tag_set.ops = &gdrom_mq_ops;
+ gd.tag_set.nr_hw_queues = 1;
+ gd.tag_set.queue_depth = 1;
+ gd.tag_set.numa_node = NUMA_NO_NODE;
+ gd.tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING;
+ err = blk_mq_alloc_tag_set(&td.tag_set);
+ if (err)
+ goto probe_fail_requestq;
+
+ gd.gdrom_rq = blk_mq_init_queue(set);
+ 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();
@@ -831,6 +822,7 @@ static int probe_gdrom(struct platform_device *devptr)
return 0;

probe_fail_toc:
+ blk_mq_free_tag_set(&gd.tag_set);
blk_cleanup_queue(gd.gdrom_rq);
probe_fail_requestq:
free_irq(HW_EVENT_GDROM_DMA, &gd);
@@ -849,7 +841,7 @@ static int probe_gdrom(struct platform_device *devptr)

static int remove_gdrom(struct platform_device *devptr)
{
- flush_work(&work);
+ blk_mq_free_tag_set(&gd.tag_set);
blk_cleanup_queue(gd.gdrom_rq);
free_irq(HW_EVENT_GDROM_CMD, &gd);
free_irq(HW_EVENT_GDROM_DMA, &gd);
--
2.17.1