2010-02-22 13:35:13

by Akinobu Mita

[permalink] [raw]
Subject: [PATCH] pktcdvd: use BIO list management functions

Now that the bio list management stuff is generic, convert pktcdvd to
use bio lists instead of its own private bio list implementation.

Signed-off-by: Akinobu Mita <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Christoph Hellwig <[email protected]>
---
drivers/block/pktcdvd.c | 89 +++++++++++------------------------------------
include/linux/pktcdvd.h | 10 ++---
2 files changed, 25 insertions(+), 74 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 68b5957..7cd2973 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -569,6 +569,7 @@ static struct packet_data *pkt_alloc_packet_data(int frames)
}

spin_lock_init(&pkt->lock);
+ bio_list_init(&pkt->orig_bios);

for (i = 0; i < frames; i++) {
struct bio *bio = pkt_bio_alloc(1);
@@ -721,43 +722,6 @@ static void pkt_rbtree_insert(struct pktcdvd_device *pd, struct pkt_rb_node *nod
}

/*
- * Add a bio to a single linked list defined by its head and tail pointers.
- */
-static void pkt_add_list_last(struct bio *bio, struct bio **list_head, struct bio **list_tail)
-{
- bio->bi_next = NULL;
- if (*list_tail) {
- BUG_ON((*list_head) == NULL);
- (*list_tail)->bi_next = bio;
- (*list_tail) = bio;
- } else {
- BUG_ON((*list_head) != NULL);
- (*list_head) = bio;
- (*list_tail) = bio;
- }
-}
-
-/*
- * Remove and return the first bio from a single linked list defined by its
- * head and tail pointers.
- */
-static inline struct bio *pkt_get_list_first(struct bio **list_head, struct bio **list_tail)
-{
- struct bio *bio;
-
- if (*list_head == NULL)
- return NULL;
-
- bio = *list_head;
- *list_head = bio->bi_next;
- if (*list_head == NULL)
- *list_tail = NULL;
-
- bio->bi_next = NULL;
- return bio;
-}
-
-/*
* Send a packet_command to the underlying block device and
* wait for completion.
*/
@@ -876,13 +840,10 @@ static noinline_for_stack int pkt_set_speed(struct pktcdvd_device *pd,
static void pkt_queue_bio(struct pktcdvd_device *pd, struct bio *bio)
{
spin_lock(&pd->iosched.lock);
- if (bio_data_dir(bio) == READ) {
- pkt_add_list_last(bio, &pd->iosched.read_queue,
- &pd->iosched.read_queue_tail);
- } else {
- pkt_add_list_last(bio, &pd->iosched.write_queue,
- &pd->iosched.write_queue_tail);
- }
+ if (bio_data_dir(bio) == READ)
+ bio_list_add(&pd->iosched.read_queue, bio);
+ else
+ bio_list_add(&pd->iosched.write_queue, bio);
spin_unlock(&pd->iosched.lock);

atomic_set(&pd->iosched.attention, 1);
@@ -917,8 +878,8 @@ static void pkt_iosched_process_queue(struct pktcdvd_device *pd)
int reads_queued, writes_queued;

spin_lock(&pd->iosched.lock);
- reads_queued = (pd->iosched.read_queue != NULL);
- writes_queued = (pd->iosched.write_queue != NULL);
+ reads_queued = !bio_list_empty(&pd->iosched.read_queue);
+ writes_queued = !bio_list_empty(&pd->iosched.write_queue);
spin_unlock(&pd->iosched.lock);

if (!reads_queued && !writes_queued)
@@ -927,7 +888,7 @@ static void pkt_iosched_process_queue(struct pktcdvd_device *pd)
if (pd->iosched.writing) {
int need_write_seek = 1;
spin_lock(&pd->iosched.lock);
- bio = pd->iosched.write_queue;
+ bio = bio_list_peek(&pd->iosched.write_queue);
spin_unlock(&pd->iosched.lock);
if (bio && (bio->bi_sector == pd->iosched.last_write))
need_write_seek = 0;
@@ -950,13 +911,10 @@ static void pkt_iosched_process_queue(struct pktcdvd_device *pd)
}

spin_lock(&pd->iosched.lock);
- if (pd->iosched.writing) {
- bio = pkt_get_list_first(&pd->iosched.write_queue,
- &pd->iosched.write_queue_tail);
- } else {
- bio = pkt_get_list_first(&pd->iosched.read_queue,
- &pd->iosched.read_queue_tail);
- }
+ if (pd->iosched.writing)
+ bio = bio_list_pop(&pd->iosched.write_queue);
+ else
+ bio = bio_list_pop(&pd->iosched.read_queue);
spin_unlock(&pd->iosched.lock);

if (!bio)
@@ -1114,7 +1072,7 @@ static void pkt_gather_data(struct pktcdvd_device *pd, struct packet_data *pkt)
int f;
char written[PACKET_MAX_SIZE];

- BUG_ON(!pkt->orig_bios);
+ BUG_ON(bio_list_empty(&pkt->orig_bios));

atomic_set(&pkt->io_wait, 0);
atomic_set(&pkt->io_errors, 0);
@@ -1124,7 +1082,7 @@ static void pkt_gather_data(struct pktcdvd_device *pd, struct packet_data *pkt)
*/
memset(written, 0, sizeof(written));
spin_lock(&pkt->lock);
- for (bio = pkt->orig_bios; bio; bio = bio->bi_next) {
+ bio_list_for_each(bio, &pkt->orig_bios) {
int first_frame = (bio->bi_sector - pkt->sector) / (CD_FRAMESIZE >> 9);
int num_frames = bio->bi_size / CD_FRAMESIZE;
pd->stats.secs_w += num_frames * (CD_FRAMESIZE >> 9);
@@ -1363,7 +1321,7 @@ try_next_bio:
break;
pkt_rbtree_erase(pd, node);
spin_lock(&pkt->lock);
- pkt_add_list_last(bio, &pkt->orig_bios, &pkt->orig_bios_tail);
+ bio_list_add(&pkt->orig_bios, bio);
pkt->write_size += bio->bi_size / CD_FRAMESIZE;
spin_unlock(&pkt->lock);
}
@@ -1409,7 +1367,7 @@ static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
*/
frames_write = 0;
spin_lock(&pkt->lock);
- for (bio = pkt->orig_bios; bio; bio = bio->bi_next) {
+ bio_list_for_each(bio, &pkt->orig_bios) {
int segment = bio->bi_idx;
int src_offs = 0;
int first_frame = (bio->bi_sector - pkt->sector) / (CD_FRAMESIZE >> 9);
@@ -1472,20 +1430,14 @@ static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)

static void pkt_finish_packet(struct packet_data *pkt, int uptodate)
{
- struct bio *bio, *next;
+ struct bio *bio;

if (!uptodate)
pkt->cache_valid = 0;

/* Finish all bios corresponding to this packet */
- bio = pkt->orig_bios;
- while (bio) {
- next = bio->bi_next;
- bio->bi_next = NULL;
+ while ((bio = bio_list_pop(&pkt->orig_bios)))
bio_endio(bio, uptodate ? 0 : -EIO);
- bio = next;
- }
- pkt->orig_bios = pkt->orig_bios_tail = NULL;
}

static void pkt_run_state_machine(struct pktcdvd_device *pd, struct packet_data *pkt)
@@ -2567,8 +2519,7 @@ static int pkt_make_request(struct request_queue *q, struct bio *bio)
spin_lock(&pkt->lock);
if ((pkt->state == PACKET_WAITING_STATE) ||
(pkt->state == PACKET_READ_WAIT_STATE)) {
- pkt_add_list_last(bio, &pkt->orig_bios,
- &pkt->orig_bios_tail);
+ bio_list_add(&pkt->orig_bios, bio);
pkt->write_size += bio->bi_size / CD_FRAMESIZE;
if ((pkt->write_size >= pkt->frames) &&
(pkt->state == PACKET_WAITING_STATE)) {
@@ -2898,6 +2849,8 @@ static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)

spin_lock_init(&pd->lock);
spin_lock_init(&pd->iosched.lock);
+ bio_list_init(&pd->iosched.read_queue);
+ bio_list_init(&pd->iosched.write_queue);
sprintf(pd->name, DRIVER_NAME"%d", idx);
init_waitqueue_head(&pd->wqueue);
pd->bio_queue = RB_ROOT;
diff --git a/include/linux/pktcdvd.h b/include/linux/pktcdvd.h
index 76e5053..721301b 100644
--- a/include/linux/pktcdvd.h
+++ b/include/linux/pktcdvd.h
@@ -163,10 +163,8 @@ struct packet_iosched
atomic_t attention; /* Set to non-zero when queue processing is needed */
int writing; /* Non-zero when writing, zero when reading */
spinlock_t lock; /* Protecting read/write queue manipulations */
- struct bio *read_queue;
- struct bio *read_queue_tail;
- struct bio *write_queue;
- struct bio *write_queue_tail;
+ struct bio_list read_queue;
+ struct bio_list write_queue;
sector_t last_write; /* The sector where the last write ended */
int successive_reads;
};
@@ -206,8 +204,8 @@ struct packet_data
spinlock_t lock; /* Lock protecting state transitions and */
/* orig_bios list */

- struct bio *orig_bios; /* Original bios passed to pkt_make_request */
- struct bio *orig_bios_tail;/* that will be handled by this packet */
+ struct bio_list orig_bios; /* Original bios passed to pkt_make_request */
+ /* that will be handled by this packet */
int write_size; /* Total size of all bios in the orig_bios */
/* list, measured in number of frames */

--
1.6.0.6


2010-02-22 13:43:27

by Akinobu Mita

[permalink] [raw]
Subject: [PATCH] blk-core: use BIO list management functions

Now that the bio list management stuff is generic, convert
generic_make_request to use bio lists instead of its own private bio
list implementation.

Signed-off-by: Akinobu Mita <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Christoph Hellwig <[email protected]>
---
block/blk-core.c | 31 ++++++++++++++-----------------
include/linux/sched.h | 4 ++--
2 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 718897e..44b6d69 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1490,9 +1490,9 @@ end_io:
/*
* We only want one ->make_request_fn to be active at a time,
* else stack usage with stacked devices could be a problem.
- * So use current->bio_{list,tail} to keep a list of requests
+ * So use current->bio_list to keep a list of requests
* submited by a make_request_fn function.
- * current->bio_tail is also used as a flag to say if
+ * current->bio_list is also used as a flag to say if
* generic_make_request is currently active in this task or not.
* If it is NULL, then no make_request is active. If it is non-NULL,
* then a make_request is active, and new requests should be added
@@ -1500,11 +1500,11 @@ end_io:
*/
void generic_make_request(struct bio *bio)
{
- if (current->bio_tail) {
+ struct bio_list bio_list_on_stack;
+
+ if (current->bio_list) {
/* make_request is active */
- *(current->bio_tail) = bio;
- bio->bi_next = NULL;
- current->bio_tail = &bio->bi_next;
+ bio_list_add(current->bio_list, bio);
return;
}
/* following loop may be a bit non-obvious, and so deserves some
@@ -1512,30 +1512,27 @@ void generic_make_request(struct bio *bio)
* Before entering the loop, bio->bi_next is NULL (as all callers
* ensure that) so we have a list with a single bio.
* We pretend that we have just taken it off a longer list, so
- * we assign bio_list to the next (which is NULL) and bio_tail
- * to &bio_list, thus initialising the bio_list of new bios to be
+ * we assign bio_list to a pointer to the bio_list_on_stack,
+ * thus initialising the bio_list of new bios to be
* added. __generic_make_request may indeed add some more bios
* through a recursive call to generic_make_request. If it
* did, we find a non-NULL value in bio_list and re-enter the loop
* from the top. In this case we really did just take the bio
- * of the top of the list (no pretending) and so fixup bio_list and
- * bio_tail or bi_next, and call into __generic_make_request again.
+ * of the top of the list (no pretending) and so remove it from
+ * bio_list, and call into __generic_make_request again.
*
* The loop was structured like this to make only one call to
* __generic_make_request (which is important as it is large and
* inlined) and to keep the structure simple.
*/
BUG_ON(bio->bi_next);
+ bio_list_init(&bio_list_on_stack);
+ current->bio_list = &bio_list_on_stack;
do {
- current->bio_list = bio->bi_next;
- if (bio->bi_next == NULL)
- current->bio_tail = &current->bio_list;
- else
- bio->bi_next = NULL;
__generic_make_request(bio);
- bio = current->bio_list;
+ bio = bio_list_pop(current->bio_list);
} while (bio);
- current->bio_tail = NULL; /* deactivate */
+ current->bio_list = NULL; /* deactivate */
}
EXPORT_SYMBOL(generic_make_request);

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 78efe7c..7eb8297 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -97,7 +97,7 @@ struct sched_param {
struct exec_domain;
struct futex_pi_state;
struct robust_list_head;
-struct bio;
+struct bio_list;
struct fs_struct;
struct bts_context;
struct perf_event_context;
@@ -1466,7 +1466,7 @@ struct task_struct {
void *journal_info;

/* stacked block device info */
- struct bio *bio_list, **bio_tail;
+ struct bio_list *bio_list;

/* VM state */
struct reclaim_state *reclaim_state;
--
1.6.0.6

2010-02-23 07:55:30

by Jens Axboe

[permalink] [raw]
Subject: Re: [PATCH] blk-core: use BIO list management functions

On Mon, Feb 22 2010, Akinobu Mita wrote:
> Now that the bio list management stuff is generic, convert
> generic_make_request to use bio lists instead of its own private bio
> list implementation.

Looks good, applied. Also saves 4 bytes in task_struct, not a bad thing
:-)

--
Jens Axboe

2010-02-23 14:26:31

by Akinobu Mita

[permalink] [raw]
Subject: Re: [PATCH] blk-core: use BIO list management functions

2010/2/23 Jens Axboe <[email protected]>:
> On Mon, Feb 22 2010, Akinobu Mita wrote:
>> Now that the bio list management stuff is generic, convert
>> generic_make_request to use bio lists instead of its own private bio
>> list implementation.
>
> Looks good, applied. Also saves 4 bytes in task_struct, not a bad thing
> :-)

Thanks.

How about another cleanup patch for pktcdvd?
http://lkml.org/lkml/2010/2/22/93

2010-02-23 14:53:30

by Jens Axboe

[permalink] [raw]
Subject: Re: [PATCH] blk-core: use BIO list management functions

On Tue, Feb 23 2010, Akinobu Mita wrote:
> 2010/2/23 Jens Axboe <[email protected]>:
> > On Mon, Feb 22 2010, Akinobu Mita wrote:
> >> Now that the bio list management stuff is generic, convert
> >> generic_make_request to use bio lists instead of its own private bio
> >> list implementation.
> >
> > Looks good, applied. Also saves 4 bytes in task_struct, not a bad thing
> > :-)
>
> Thanks.
>
> How about another cleanup patch for pktcdvd?
> http://lkml.org/lkml/2010/2/22/93

Looks fine to me, I can pick it up if need be. Peter?

--
Jens Axboe

2010-02-23 19:48:13

by Peter Osterlund

[permalink] [raw]
Subject: Re: [PATCH] blk-core: use BIO list management functions

On Tue, 23 Feb 2010, Jens Axboe wrote:

> On Tue, Feb 23 2010, Akinobu Mita wrote:
>> 2010/2/23 Jens Axboe <[email protected]>:
>>> On Mon, Feb 22 2010, Akinobu Mita wrote:
>>>> Now that the bio list management stuff is generic, convert
>>>> generic_make_request to use bio lists instead of its own private bio
>>>> list implementation.
>>>
>>> Looks good, applied. Also saves 4 bytes in task_struct, not a bad thing
>>> :-)
>>
>> Thanks.
>>
>> How about another cleanup patch for pktcdvd?
>> http://lkml.org/lkml/2010/2/22/93
>
> Looks fine to me, I can pick it up if need be. Peter?

It looks fine to me too. Please pick it up, Jens.

Thanks.

--
Peter Osterlund - [email protected]
http://web.telia.com/~u89404340

2010-02-23 22:23:04

by Jens Axboe

[permalink] [raw]
Subject: Re: [PATCH] blk-core: use BIO list management functions

On Tue, Feb 23 2010, Peter Osterlund wrote:
> On Tue, 23 Feb 2010, Jens Axboe wrote:
>
>> On Tue, Feb 23 2010, Akinobu Mita wrote:
>>> 2010/2/23 Jens Axboe <[email protected]>:
>>>> On Mon, Feb 22 2010, Akinobu Mita wrote:
>>>>> Now that the bio list management stuff is generic, convert
>>>>> generic_make_request to use bio lists instead of its own private bio
>>>>> list implementation.
>>>>
>>>> Looks good, applied. Also saves 4 bytes in task_struct, not a bad thing
>>>> :-)
>>>
>>> Thanks.
>>>
>>> How about another cleanup patch for pktcdvd?
>>> http://lkml.org/lkml/2010/2/22/93
>>
>> Looks fine to me, I can pick it up if need be. Peter?
>
> It looks fine to me too. Please pick it up, Jens.

Certainly, I'll queue it up for 2.6.34. I'm assuming I can add your
acked-by?

--
Jens Axboe

2010-02-23 23:36:00

by Peter Osterlund

[permalink] [raw]
Subject: Re: [PATCH] blk-core: use BIO list management functions

On Tue, 23 Feb 2010, Jens Axboe wrote:

> On Tue, Feb 23 2010, Peter Osterlund wrote:
>> On Tue, 23 Feb 2010, Jens Axboe wrote:
>>
>>> On Tue, Feb 23 2010, Akinobu Mita wrote:
>>>> 2010/2/23 Jens Axboe <[email protected]>:
>>>>> On Mon, Feb 22 2010, Akinobu Mita wrote:
>>>>>> Now that the bio list management stuff is generic, convert
>>>>>> generic_make_request to use bio lists instead of its own private bio
>>>>>> list implementation.
>>>>>
>>>>> Looks good, applied. Also saves 4 bytes in task_struct, not a bad thing
>>>>> :-)
>>>>
>>>> Thanks.
>>>>
>>>> How about another cleanup patch for pktcdvd?
>>>> http://lkml.org/lkml/2010/2/22/93
>>>
>>> Looks fine to me, I can pick it up if need be. Peter?
>>
>> It looks fine to me too. Please pick it up, Jens.
>
> Certainly, I'll queue it up for 2.6.34. I'm assuming I can add your
> acked-by?

Yes.

Acked-by: Peter Osterlund <[email protected]>

--
Peter Osterlund - [email protected]
http://web.telia.com/~u89404340