swim3: dequeue in-flight request

swim3 has at most single request in flight and already tracks it using
fd_req.  Convert it to dequeuing model by updating request fetching
and wrapping completion function.

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 34 insertions, 13 deletions

diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index c1b9a4dc11ba..f48c6dd47e04 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -251,6 +251,20 @@ static int floppy_release(struct gendisk *disk, fmode_t mode);
 static int floppy_check_change(struct gendisk *disk);
 static int floppy_revalidate(struct gendisk *disk);
 
+static bool swim3_end_request(int err, unsigned int nr_bytes)
+{
+        if (__blk_end_request(fd_req, err, nr_bytes))
+                return true;
+
+        fd_req = NULL;
+        return false;
+}
+
+static bool swim3_end_request_cur(int err)
+{
+        return swim3_end_request(err, blk_rq_cur_bytes(fd_req));
+}
+
 static void swim3_select(struct floppy_state *fs, int sel)
 {
         struct swim3 __iomem *sw = fs->swim3;
@@ -310,7 +324,14 @@ static void start_request(struct floppy_state *fs)
                 wake_up(&fs->wait);
                 return;
         }
-        while (fs->state == idle && (req = elv_next_request(swim3_queue))) {
+        while (fs->state == idle) {
+                if (!fd_req) {
+                        fd_req = elv_next_request(swim3_queue);
+                        if (!fd_req)
+                                break;
+                        blkdev_dequeue_request(fd_req);
+                }
+                req = fd_req;
 #if 0
                 printk("do_fd_req: dev=%s cmd=%d sec=%ld nr_sec=%u buf=%p\n",
                        req->rq_disk->disk_name, req->cmd,
@@ -320,11 +341,11 @@ static void start_request(struct floppy_state *fs)
 #endif
 
                 if (blk_rq_pos(req) >= fs->total_secs) {
-                        __blk_end_request_cur(req, -EIO);
+                        swim3_end_request_cur(-EIO);
                         continue;
                 }
                 if (fs->ejected) {
-                        __blk_end_request_cur(req, -EIO);
+                        swim3_end_request_cur(-EIO);
                         continue;
                 }
 
@@ -332,7 +353,7 @@ static void start_request(struct floppy_state *fs)
                         if (fs->write_prot < 0)
                                 fs->write_prot = swim3_readbit(fs, WRITE_PROT);
                         if (fs->write_prot) {
-                                __blk_end_request_cur(req, -EIO);
+                                swim3_end_request_cur(-EIO);
                                 continue;
                         }
                 }
@@ -505,7 +526,7 @@ static void act(struct floppy_state *fs)
                 case do_transfer:
                         if (fs->cur_cyl != fs->req_cyl) {
                                 if (fs->retries > 5) {
-                                        __blk_end_request_cur(fd_req, -EIO);
+                                        swim3_end_request_cur(-EIO);
                                         fs->state = idle;
                                         return;
                                 }
@@ -537,7 +558,7 @@ static void scan_timeout(unsigned long data)
         out_8(&sw->intr_enable, 0);
         fs->cur_cyl = -1;
         if (fs->retries > 5) {
-                __blk_end_request_cur(fd_req, -EIO);
+                swim3_end_request_cur(-EIO);
                 fs->state = idle;
                 start_request(fs);
         } else {
@@ -556,7 +577,7 @@ static void seek_timeout(unsigned long data)
         out_8(&sw->select, RELAX);
         out_8(&sw->intr_enable, 0);
         printk(KERN_ERR "swim3: seek timeout\n");
-        __blk_end_request_cur(fd_req, -EIO);
+        swim3_end_request_cur(-EIO);
         fs->state = idle;
         start_request(fs);
 }
@@ -580,7 +601,7 @@ static void settle_timeout(unsigned long data)
                 return;
         }
         printk(KERN_ERR "swim3: seek settle timeout\n");
-        __blk_end_request_cur(fd_req, -EIO);
+        swim3_end_request_cur(-EIO);
         fs->state = idle;
         start_request(fs);
 }
@@ -603,7 +624,7 @@ static void xfer_timeout(unsigned long data)
         printk(KERN_ERR "swim3: timeout %sing sector %ld\n",
                (rq_data_dir(fd_req)==WRITE? "writ": "read"),
                (long)blk_rq_pos(fd_req));
-        __blk_end_request_cur(fd_req, -EIO);
+        swim3_end_request_cur(-EIO);
         fs->state = idle;
         start_request(fs);
 }
@@ -634,7 +655,7 @@ static irqreturn_t swim3_interrupt(int irq, void *dev_id)
                                 printk(KERN_ERR "swim3: seen sector but cyl=ff?\n");
                                 fs->cur_cyl = -1;
                                 if (fs->retries > 5) {
-                                        __blk_end_request_cur(fd_req, -EIO);
+                                        swim3_end_request_cur(-EIO);
                                         fs->state = idle;
                                         start_request(fs);
                                 } else {
@@ -717,7 +738,7 @@ static irqreturn_t swim3_interrupt(int irq, void *dev_id)
                                 printk("swim3: error %sing block %ld (err=%x)\n",
                                        rq_data_dir(fd_req) == WRITE? "writ": "read",
                                        (long)blk_rq_pos(fd_req), err);
-                                __blk_end_request_cur(fd_req, -EIO);
+                                swim3_end_request_cur(-EIO);
                                 fs->state = idle;
                         }
                 } else {
@@ -726,12 +747,12 @@ static irqreturn_t swim3_interrupt(int irq, void *dev_id)
                                 printk(KERN_ERR "swim3: fd dma: stat=%x resid=%d\n", stat, resid);
                                 printk(KERN_ERR "  state=%d, dir=%x, intr=%x, err=%x\n",
                                        fs->state, rq_data_dir(fd_req), intr, err);
-                                __blk_end_request_cur(fd_req, -EIO);
+                                swim3_end_request_cur(-EIO);
                                 fs->state = idle;
                                 start_request(fs);
                                 break;
                         }
-                        if (__blk_end_request(fd_req, 0, fs->scount << 9)) {
+                        if (swim3_end_request(0, fs->scount << 9)) {
                                 fs->req_sector += fs->scount;
                                 if (fs->req_sector > fs->secpertrack) {
                                         fs->req_sector -= fs->secpertrack;