Hello, I wrote:
Oops, sent this message only to Tejun before, so have to repost now...
z2ram processes requests one-by-one synchronously and can be easily
converted to dequeueing model. Convert it.
[ Impact: dequeue in-flight request ]
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
drivers/block/z2ram.c | 19 +++++++++++++++----
1 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 6a13838..c909c1a 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -70,15 +70,21 @@ static struct gendisk *z2ram_gendisk;
static void do_z2_request(struct request_queue *q)
{
struct request *req;
- while ((req = elv_next_request(q)) != NULL) {
+
+ req = elv_next_request(q);
+ if (req)
+ blkdev_dequeue_request(req);
+
+ while (req) {
unsigned long start = blk_rq_pos(req) << 9;
unsigned long len = blk_rq_cur_bytes(req);
+ int err = 0;
if (start + len > z2ram_size) {
printk( KERN_ERR DEVICE_NAME ": bad access: block=%lu,
count=%u\n",
blk_rq_pos(req), blk_rq_cur_sectors(req));
- __blk_end_request_cur(req, -EIO);
- continue;
+ err = -EIO;
+ goto done;
}
while (len) {
unsigned long addr = start & Z2RAM_CHUNKMASK;
@@ -93,7 +99,12 @@ static void do_z2_request(struct request_queue *q)
start += size;
len -= size;
}
- __blk_end_request_cur(req, 0);
+ done:
+ if (!__blk_end_request_cur(req, err)) {
+ req = elv_next_request(q);
+ if (req)
+ blkdev_dequeue_request(req);
+ }
}
}
I'm sure this can be made more compact and without duplication (in
many other cases as well):
@@ -70,15 +70,21 @@ static struct gendisk *z2ram_gendisk;
static void do_z2_request(struct request_queue *q)
{
struct request *req;
+
while ((req = elv_next_request(q)) != NULL) {
unsigned long start = blk_rq_pos(req) << 9;
unsigned long len = blk_rq_cur_bytes(req);
Oops, missed:
+ int err;
+
+ blkdev_dequeue_request(req);
+
+again:
if (start + len > z2ram_size) {
printk( KERN_ERR DEVICE_NAME ": bad access: block=%lu,
count=%u\n",
blk_rq_pos(req), blk_rq_cur_sectors(req));
- __blk_end_request_cur(req, -EIO);
- continue;
+ err = -EIO;
+ goto done;
}
while (len) {
unsigned long addr = start & Z2RAM_CHUNKMASK;
@@ -93,7 +99,12 @@ static void do_z2_request(struct request_queue *q)
start += size;
len -= size;
}
- __blk_end_request_cur(req, 0);
+ err = 0;
+ done:
+ if (__blk_end_request_cur(req, err));
+ break;
Oops, should've been:
+ if (__blk_end_request_cur(req, err))
+ goto again;
}
}
It can also be:
@@ -70,15 +70,21 @@ static struct gendisk *z2ram_gendisk;
static void do_z2_request(struct request_queue *q)
{
- struct request *req;
- while ((req = elv_next_request(q)) != NULL) {
+ while (1) {
+ struct request *req = elv_next_request(q);
+ unsigned long start, len;
+ int err;
+
+ if (req == NULL)
+ break;
+
+ blkdev_dequeue_request(req);
+
+again:
+ start = blk_rq_pos(req) << 9;
+ len = blk_rq_cur_bytes(req);
if (start + len > z2ram_size) {
printk( KERN_ERR DEVICE_NAME ": bad access: block=%lu,
count=%u\n",
blk_rq_pos(req), blk_rq_cur_sectors(req));
- __blk_end_request_cur(req, -EIO);
- continue;
+ err = -EIO;
+ goto done;
}
while (len) {
unsigned long addr = start & Z2RAM_CHUNKMASK;
@@ -93,7 +99,12 @@ static void do_z2_request(struct request_queue *q)
start += size;
len -= size;
}
- __blk_end_request_cur(req, 0);
+ err = 0;
+ done:
+ if (__blk_end_request_cur(req, err))
+ goto again;
}
}
if you want to get rid of the assignement in the *while* statement...
MBR, Sergei
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