[RFC][PATCH] MD RAID Acceleration: Move stripe operations outsidethe spin lock

From: Dan Williams
Date: Tue May 16 2006 - 18:23:06 EST

This is the second revision of the effort to enable offload of MD's xor
and copy operations to dedicated hardware resources. Please comment on
the approach of this patch and whether it will be suitable to expand
this to the other areas in handle_stripe where such calculations are
performed. Implementation of the xor offload API is a work in progress,
the intent is to reuse I/OAT.

Overview:
Neil, as you recommended, this implementation flags the necessary
operations on a stripe and then queues the execution to a separate
thread (similar to how disk cycles are handled). See the comments added
to raid5.h for more details.

This was prepared before the raid5/raid6 merge, and applies against
Linus' git tree at commit 716f8954fb3029ca2df52a986b60af8d06f093ee

---

[PATCH] Move stripe operations outside the spin lock

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>

---

drivers/md/raid5.c | 391 ++++++++++++++++++++++++++++++++++++++++++--
include/linux/raid/raid5.h | 52 ++++++
2 files changed, 422 insertions(+), 21 deletions(-)

cb744f0f0ea60afd7c847f6dc4e5ebaad7faee90
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 3184360..9f7ae26 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -862,6 +862,144 @@ static void compute_block(struct stripe_
set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
}

+static int handle_write_operations(struct stripe_head *sh, int rcw)
+{
+ int i, pd_idx = sh->pd_idx, disks = sh->disks;
+ int ops=0, start=0, rcw_complete=0, rmw_complete=0;
+
+ PRINTK("%s, stripe %llu, state %lx\n",
+ __FUNCTION__, (unsigned long long)sh->sector, sh->state);
+
+ /* If no operation is currently pending use the rcw flag to
+ * select an operation
+ */
+ if (!(test_bit(STRIPE_OP_RCW, &sh->state) ||
+ test_bit(STRIPE_OP_RMW, &sh->state))) {
+ if (rcw==0)
+ set_bit(STRIPE_OP_RCW, &sh->state);
+ else {
+ BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags));
+ set_bit(STRIPE_OP_RMW, &sh->state);
+ }
+ start++;
+ } else if (unlikely(test_bit(STRIPE_OP_RCW, &sh->state) &&
+ test_bit(STRIPE_OP_RMW, &sh->state)))
+ BUG();
+
+ if (test_bit(STRIPE_OP_RMW, &sh->state)) {
+ for (i=disks ; i-- ;) {
+ struct r5dev *dev = &sh->dev[i];
+ if (i==pd_idx)
+ continue;
+
+ /* enter stage 1 of read modify write operation
+ * (prevent new rmw operations while one is in flight)
+ */
+ if (start && dev->towrite &&
+ test_bit(R5_UPTODATE, &dev->flags)) {
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_WantRMWXorPre, &dev->flags);
+ ops++;
+ /* stage 1 -> stage 2 */
+ } else if (test_and_clear_bit(R5_WantRMWXorPre,
+ &dev->flags)) {
+ set_bit(R5_WantRMWDrain, &dev->flags);
+ ops++;
+ /* stage 2 -> stage 3 */
+ } else if (test_and_clear_bit(R5_WantRMWDrain,
+ &dev->flags)) {
+ set_bit(R5_WantRMWXorPost, &dev->flags);
+ set_bit(R5_UPTODATE, &dev->flags);
+ ops++;
+ /* stage 3 -> completion */
+ } else if (test_and_clear_bit(R5_WantRMWXorPost,
+ &dev->flags)) {
+ /* synchronous block_ops routines may be done
+ * at this point
+ */
+ if (test_bit(STRIPE_OP_RMW, &sh->op_completion))
+ rmw_complete++;
+ /* signal the workqueue to complete this op */
+ else {
+ set_bit(R5_WantRMWCompletion,
+ &dev->flags);
+ ops++;
+ }
+ /* finish read modify write */
+ } else if (test_and_clear_bit(R5_WantRMWCompletion,
+ &dev->flags))
+ rmw_complete++;
+ }
+ } else if (test_bit(STRIPE_OP_RCW, &sh->state)) {
+ for (i=disks ; i-- ;) {
+ int pd_start=0;
+ struct r5dev *dev = &sh->dev[i];
+
+ /* enter stage 1 of reconstruct write operation
+ * (prevent new rcw operations while one is in flight)
+ */
+ if (start && i!=pd_idx && dev->towrite) {
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_WantRCWDrain, &dev->flags);
+ /* The parity disk 'zero' operation can run concurrently
+ * with the bio drain
+ */
+ if (!pd_start) {
+ pd_start++;
+ set_bit(R5_WantZero, &sh->dev[pd_idx].flags);
+ }
+ ops++;
+ /* stage 1 -> stage 2 */
+ } else if (test_and_clear_bit(R5_WantRCWDrain,
+ &dev->flags)) {
+ set_bit(R5_UPTODATE, &dev->flags);
+ set_bit(R5_WantRCWXor, &dev->flags);
+ ops++;
+ /* stage 2 -> completion */
+ } else if (test_and_clear_bit(R5_WantRCWXor,
+ &dev->flags)) {
+ /* synchronous block_ops routines may be done
+ * at this point
+ */
+ if (test_bit(STRIPE_OP_RCW, &sh->op_completion))
+ rcw_complete++;
+ /* signal the workqueue to complete this op */
+ else {
+ set_bit(R5_WantRCWCompletion,
+ &dev->flags);
+ ops++;
+ }
+ /* finish reconstruct write */
+ } else if (test_and_clear_bit(R5_WantRCWCompletion,
+ &dev->flags))
+ rcw_complete++;
+ }
+ }
+
+ /* keep the parity disk locked while asynchronous operations
+ * are in flight
+ */
+ if (ops) {
+ set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
+ clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
+ set_bit(STRIPE_OP_LOCKED, &sh->state);
+ sh->op_count++;
+ } else {
+ set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
+ /* to do: add assertions if (rcw_complete || rmw_complete) != nr disks */
+ if (rcw_complete) {
+ clear_bit(STRIPE_OP_RCW, &sh->state);
+ clear_bit(STRIPE_OP_RCW, &sh->op_completion);
+ }
+ if (rmw_complete) {
+ clear_bit(STRIPE_OP_RMW, &sh->state);
+ clear_bit(STRIPE_OP_RMW, &sh->op_completion);
+ }
+ }
+
+ return ops;
+}
+
static void compute_parity(struct stripe_head *sh, int method)
{
raid5_conf_t *conf = sh->raid_conf;
@@ -1044,6 +1182,133 @@ static int stripe_to_pdidx(sector_t stri
}


+static inline void drain_bio(struct bio *wbi, sector_t sector, struct page *page)
+{
+ while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
+ copy_data(1, wbi, page, sector);
+ wbi = r5_next_bio(wbi, sector);
+ }
+}
+
+/*
+ * raid5_do_soft_block_ops - perform block memory operations on stripe data
+ * outside the spin lock.
+ */
+static void raid5_do_soft_block_ops(void *stripe_work_data)
+{
+ struct stripe_work *sw = stripe_work_data;
+ struct stripe_head *sh = sw->sh;
+ raid5_conf_t *conf = sh->raid_conf;
+ int i, pd_idx = sh->pd_idx, disks = sh->disks, count = 1;
+ void *ptr[MAX_XOR_BLOCKS];
+ struct bio *chosen;
+ int overlap=0, rmw_complete=0, rcw_complete=0;
+
+ /* release resources for next op to be queued */
+ if (unlikely(sw->lock))
+ mutex_unlock(sw->lock);
+ else
+ kfree(sw);
+
+ /* it is safe to read the state bits outside the stripe lock because the
+ * the stripe will be on the wait_for_block_ops queue or pending in the
+ * handle_list
+ */
+ if (test_bit(STRIPE_OP_RMW, &sh->state)) {
+ PRINTK("%s: stripe %llu STRIPE_OP_RMW\n", __FUNCTION__,
+ (unsigned long long)sh->sector);
+
+ ptr[0] = page_address(sh->dev[pd_idx].page);
+
+ for (i=disks ; i-- ;) {
+ struct r5dev *dev = &sh->dev[i];
+ if (test_bit(R5_WantRMWXorPre, &dev->flags)) {
+ ptr[count++] = page_address(dev->page);
+ /* ? is the device_lock necessary; compute_parity
+ * does not lock for this operation ?
+ */
+ chosen = dev->towrite;
+ dev->towrite = NULL;
+
+ overlap++;
+
+ BUG_ON(dev->written);
+ dev->written = chosen;
+ check_xor();
+ } else if (test_bit(R5_WantRMWDrain, &dev->flags)) {
+ drain_bio(dev->written,
+ dev->sector,
+ dev->page);
+ } else if (test_bit(R5_WantRMWXorPost, &dev->flags)) {
+ ptr[count++] = page_address(dev->page);
+ check_xor();
+ rmw_complete++;
+ } else if (test_bit(R5_WantCompletion, &dev->flags))
+ rmw_complete++;
+ }
+ } else if (test_bit(STRIPE_OP_RCW, &sh->state)) {
+ PRINTK("%s: stripe %llu STRIPE_OP_RCW\n", __FUNCTION__,
+ (unsigned long long)sh->sector);
+
+ ptr[0] = page_address(sh->dev[pd_idx].page);
+
+ for (i= disks; i-- ;) {
+ struct r5dev *dev = &sh->dev[i];
+ if (i==pd_idx && test_bit(R5_WantZero, &dev->flags)) {
+ memset(ptr[0], 0, STRIPE_SIZE);
+ } else if (test_bit(R5_WantRCWDrain, &dev->flags)) {
+ /* ? is the device_lock necessary; compute_parity
+ * does not lock for this operation ?
+ */
+ chosen = dev->towrite;
+ dev->towrite = NULL;
+
+ BUG_ON(dev->written);
+ dev->written = chosen;
+
+ overlap++;
+
+ drain_bio(dev->written,
+ dev->sector,
+ dev->page);
+ } else if (test_bit(R5_WantRCWXor, &dev->flags)) {
+ ptr[count++] = page_address(dev->page);
+ check_xor();
+ rcw_complete++;
+ } else if (test_bit(R5_WantCompletion, &dev->flags))
+ rcw_complete++;
+
+ }
+ }
+
+ if (count != 1)
+ xor_block(count, STRIPE_SIZE, ptr);
+
+ /* We lock the stripe to ensure handle_stripe is
+ * not running while we signal completion of operations
+ */
+ spin_lock(&sh->lock);
+ if (! --sh->op_count) {
+ clear_bit(STRIPE_OP_LOCKED, &sh->state);
+ wake_up(&conf->wait_for_block_op);
+ }
+
+ if (rmw_complete)
+ set_bit(STRIPE_OP_RMW, &sh->op_completion);
+ if (rcw_complete)
+ set_bit(STRIPE_OP_RCW, &sh->op_completion);
+
+ if (overlap)
+ for (i= disks; i-- ;) {
+ struct r5dev *dev = &sh->dev[i];
+ if (test_and_clear_bit(R5_Overlap, &dev->flags))
+ wake_up(&conf->wait_for_overlap);
+ }
+ spin_unlock(&sh->lock);
+}
+
+static struct stripe_work stripe_work_low_mem;
+static struct mutex stripe_work_mutex;
/*
* handle_stripe - do things to a stripe.
*
@@ -1056,12 +1321,10 @@ static int stripe_to_pdidx(sector_t stri
* schedule a write of some buffers
* return confirmation of parity correctness
*
- * Parity calculations are done inside the stripe lock
* buffers are taken off read_list or write_list, and bh_cache buffers
* get BH_Lock set before the stripe lock is released.
*
*/
-
static void handle_stripe(struct stripe_head *sh)
{
raid5_conf_t *conf = sh->raid_conf;
@@ -1073,13 +1336,25 @@ static void handle_stripe(struct stripe_
int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
int non_overwrite = 0;
int failed_num=0;
+ int block_ops=0;
struct r5dev *dev;
+ DEFINE_WAIT(wait);
+
+block_op_retry:
+ prepare_to_wait(&conf->wait_for_block_op, &wait, TASK_UNINTERRUPTIBLE);

PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
(unsigned long long)sh->sector, atomic_read(&sh->count),
sh->pd_idx);

spin_lock(&sh->lock);
+ if (test_bit(STRIPE_OP_LOCKED, &sh->state))
+ /* wait for the work queue to dequeue the request */
+ goto block_op_locked;
+ else
+ /* advance the stripe state */
+ finish_wait(&conf->wait_for_block_op, &wait);
+
clear_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);

@@ -1152,6 +1427,8 @@ static void handle_stripe(struct stripe_
* need to be failed
*/
if (failed > 1 && to_read+to_write+written) {
+ int rmw_op = test_and_clear_bit(STRIPE_OP_RMW, &sh->state) ? 1 : 0;
+ int rcw_op = test_and_clear_bit(STRIPE_OP_RCW, &sh->state) ? 1 : 0;
for (i=disks; i--; ) {
int bitmap_end = 0;

@@ -1167,6 +1444,19 @@ static void handle_stripe(struct stripe_

spin_lock_irq(&conf->device_lock);
/* fail all writes first */
+ /* cancel the write operations state machine */
+ if (rmw_op) {
+ clear_bit(R5_WantRMWXorPre, &sh->dev[i].flags);
+ clear_bit(R5_WantRMWDrain, &sh->dev[i].flags);
+ clear_bit(R5_WantRMWXorPost, &sh->dev[i].flags);
+ clear_bit(R5_WantRMWCompletion, &sh->dev[i].flags);
+ }
+ if (rcw_op) {
+ clear_bit(R5_WantRCWDrain, &sh->dev[i].flags);
+ clear_bit(R5_WantRCWXor, &sh->dev[i].flags);
+ clear_bit(R5_WantRCWCompletion, &sh->dev[i].flags);
+ }
+
bi = sh->dev[i].towrite;
sh->dev[i].towrite = NULL;
if (bi) { to_write--; bitmap_end = 1; }
@@ -1319,7 +1609,8 @@ #endif
}

/* now to consider writing and what else, if anything should be read */
- if (to_write) {
+ if (to_write || test_bit(STRIPE_OP_RCW, &sh->state) ||
+ test_bit(STRIPE_OP_RMW, &sh->state)) {
int rmw=0, rcw=0;
for (i=disks ; i--;) {
/* would I have to read this buffer for read_modify_write */
@@ -1391,24 +1682,32 @@ #endif
}
}
/* now if nothing is locked, and if we have enough data, we can start a write request */
- if (locked == 0 && (rcw == 0 ||rmw == 0) &&
- !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
- PRINTK("Computing parity...\n");
- compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
- /* now every locked buffer is ready to be written */
- for (i=disks; i--;)
- if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
- PRINTK("Writing block %d\n", i);
- locked++;
- set_bit(R5_Wantwrite, &sh->dev[i].flags);
- if (!test_bit(R5_Insync, &sh->dev[i].flags)
- || (i==sh->pd_idx && failed == 0))
- set_bit(STRIPE_INSYNC, &sh->state);
+ /* ...or, if we have previously started write operations we can now advance the state */
+ if ((locked == 0 && (rcw == 0 ||rmw == 0) &&
+ !test_bit(STRIPE_BIT_DELAY, &sh->state)) ||
+ test_bit(STRIPE_OP_RCW, &sh->state) || test_bit(STRIPE_OP_RMW, &sh->state)) {
+ int block_ops_prev = block_ops;
+ block_ops += handle_write_operations(sh, rcw);
+ if ((block_ops - block_ops_prev) == 0) {
+ /* now every locked buffer is ready to be written */
+ for (i=disks; i--;)
+ if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
+ PRINTK("Writing block %d\n", i);
+ locked++;
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+ if (!test_bit(R5_Insync, &sh->dev[i].flags)
+ || (i==sh->pd_idx && failed == 0))
+ set_bit(STRIPE_INSYNC, &sh->state);
+ }
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
+ atomic_dec(&conf->preread_active_stripes);
+ if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
+ md_wakeup_thread(conf->mddev->thread);
}
- if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
- atomic_dec(&conf->preread_active_stripes);
- if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
- md_wakeup_thread(conf->mddev->thread);
+ } else {
+ set_bit(STRIPE_HANDLE, &sh->state);
+ if (locked == 0)
+ locked += block_ops - block_ops_prev;
}
}
}
@@ -1555,6 +1854,27 @@ #endif
bi->bi_size = 0;
bi->bi_end_io(bi, bytes, 0);
}
+
+ if (block_ops) {
+ struct stripe_work *sw = kmalloc(sizeof(*sw),
+ GFP_KERNEL);
+
+ /* in the memory allocation failure case
+ * use a static resource to keep operations
+ * limping along until memory frees up
+ */
+ if (unlikely(!sw)) {
+ mutex_lock(&stripe_work_mutex);
+ sw = &stripe_work_low_mem;
+ sw->lock = &stripe_work_mutex;
+ } else
+ sw->lock = NULL;
+
+ INIT_WORK(&sw->work, conf->do_block_ops, sw);
+ sw->sh = sh;
+ queue_work(conf->block_ops_queue, &sw->work);
+ }
+
for (i=disks; i-- ;) {
int rw;
struct bio *bi;
@@ -1613,6 +1933,15 @@ #endif
set_bit(STRIPE_HANDLE, &sh->state);
}
}
+
+ return;
+
+block_op_locked:
+ spin_unlock(&sh->lock);
+ schedule();
+ PRINTK("stripe %llu woke up from block op wait queue\n",
+ (unsigned long long)sh->sector);
+ goto block_op_retry;
}

static void raid5_activate_delayed(raid5_conf_t *conf)
@@ -2251,9 +2580,28 @@ static int run(mddev_t *mddev)
if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
goto abort;

+ sprintf(conf->workqueue_name, "%s_raid5_ops",
+ mddev->gendisk->disk_name);
+
+ /* use a single threaded work queue to maintain ordering */
+ if ((conf->block_ops_queue = __create_workqueue(conf->workqueue_name, 1))
+ == NULL)
+ goto abort;
+
+ mutex_init(&stripe_work_mutex);
+
+ /* To Do:
+ * 1/ Offload to asynchronous copy / xor engines
+ * 2/ Offload to multiple cpus
+ * 3/ Automated selection of optimal do_block_ops
+ * routine similar to the xor template selection
+ */
+ conf->do_block_ops = raid5_do_soft_block_ops;
+
spin_lock_init(&conf->device_lock);
init_waitqueue_head(&conf->wait_for_stripe);
init_waitqueue_head(&conf->wait_for_overlap);
+ init_waitqueue_head(&conf->wait_for_block_op);
INIT_LIST_HEAD(&conf->handle_list);
INIT_LIST_HEAD(&conf->delayed_list);
INIT_LIST_HEAD(&conf->bitmap_list);
@@ -2401,6 +2749,8 @@ abort:
print_raid5_conf(conf);
kfree(conf->disks);
kfree(conf->stripe_hashtbl);
+ if (conf->block_ops_queue)
+ destroy_workqueue(conf->block_ops_queue);
kfree(conf);
}
mddev->private = NULL;
@@ -2421,6 +2771,7 @@ static int stop(mddev_t *mddev)
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
kfree(conf->disks);
+ destroy_workqueue(conf->block_ops_queue);
kfree(conf);
mddev->private = NULL;
return 0;
diff --git a/include/linux/raid/raid5.h b/include/linux/raid/raid5.h
index 914af66..8225dda 100644
--- a/include/linux/raid/raid5.h
+++ b/include/linux/raid/raid5.h
@@ -3,6 +3,7 @@ #define _RAID5_H

#include <linux/raid/md.h>
#include <linux/raid/xor.h>
+#include <linux/workqueue.h>

/*
*
@@ -123,6 +124,17 @@ #include <linux/raid/xor.h>
* The refcount counts each thread that have activated the stripe,
* plus raid5d if it is handling it, plus one for each active request
* on a cached buffer.
+ *
+ * Block operations (copy, xor, block fill, and block compare) are executed
+ * outside the spin lock. A stripe can have at maximum one pending request
+ * in the workqueue at a time (* some operations may be able to run concurrently,
+ * but this is a work in progress). The STRIPE_OP_LOCK bit prevents threads from
+ * advancing the operations state machine before the work queue has had a chance
+ * to dequeue the request. Note that this lock is only held for the enqueue/dequeue
+ * duration. The conf->do_block_ops routine is free to submit the operation to an
+ * asynchronous engine and release the lock, as long as it maintains the completion
+ * order of events. The operations state machine sends a completion request when it
+ * is time to submit the result down to disk, or up to the filesystem.
*/

struct stripe_head {
@@ -133,6 +145,8 @@ struct stripe_head {
int pd_idx; /* parity disk index */
unsigned long state; /* state flags */
atomic_t count; /* nr of active thread/requests */
+ int op_count; /* nr of queued block operations */
+ unsigned long op_completion; /* ops completion flags */
spinlock_t lock;
int bm_seq; /* sequence number for bitmap flushes */
int disks; /* disks in stripe */
@@ -145,6 +159,13 @@ struct stripe_head {
unsigned long flags;
} dev[1]; /* allocated with extra space depending of RAID geometry */
};
+
+struct stripe_work {
+ struct work_struct work;
+ struct mutex *lock;
+ struct stripe_head *sh;
+};
+
/* Flags */
#define R5_UPTODATE 0 /* page contains current data */
#define R5_LOCKED 1 /* IO has been submitted on "req" */
@@ -156,8 +177,25 @@ #define R5_Wantwrite 5
#define R5_Overlap 7 /* There is a pending overlapping request on this block */
#define R5_ReadError 8 /* seen a read error here recently */
#define R5_ReWrite 9 /* have tried to over-write the readerror */
-
#define R5_Expanded 10 /* This block now has post-expand data */
+/* block operations handled by the work queue */
+#define R5_WantZero 11 /* Prep a block to be overwritten */
+#define R5_WantBioDrain 12 /* Drain the write data out of the bio(s) */
+#define R5_WantBioFill 13 /* Copy read data into bio(s) */
+#define R5_WantCompletion 14 /* Flush pending operations */
+#define R5_WantRCWDrain R5_WantBioDrain
+#define R5_WantRCWXor 15 /* Compute parity across the entire stripe */
+#define R5_WantRCWCompletion R5_WantCompletion
+#define R5_WantRMWXorPre 16 /* Compute initial parity for read modify write*/
+#define R5_WantRMWDrain R5_WantBioDrain
+#define R5_WantRMWXorPost 17 /* Recompute parity across updated stripes */
+#define R5_WantRMWCompletion R5_WantCompletion
+#define R5_WantCheckGen R5_WantRCWXor
+#define R5_WantCheckVerify 18 /* Verify the parity sums to zero */
+#define R5_WantComputeBlockPrep 19 /* Hold off state transitions until DD ready */
+#define R5_WantComputeBlockXor 20 /* Recover block via xor */
+#define R5_Consistent 21 /* Block is HW DMA-able */
+
/*
* Write method
*/
@@ -179,6 +217,12 @@ #define STRIPE_BIT_DELAY 8
#define STRIPE_EXPANDING 9
#define STRIPE_EXPAND_SOURCE 10
#define STRIPE_EXPAND_READY 11
+#define STRIPE_OP_RCW 12
+#define STRIPE_OP_RMW 13
+#define STRIPE_OP_CHECK 14
+#define STRIPE_OP_COMPUTE 15
+#define STRIPE_OP_BIOFILL 16
+#define STRIPE_OP_LOCKED 17
/*
* Plugging:
*
@@ -228,11 +272,16 @@ struct raid5_private_data {
atomic_t preread_active_stripes; /* stripes with scheduled io */

atomic_t reshape_stripes; /* stripes with pending writes for reshape */
+
+ struct workqueue_struct *block_ops_queue;
+ void (*do_block_ops)(void *);
+
/* unfortunately we need two cache names as we temporarily have
* two caches.
*/
int active_name;
char cache_name[2][20];
+ char workqueue_name[20];
kmem_cache_t *slab_cache; /* for allocating stripes */

int seq_flush, seq_write;
@@ -252,6 +301,7 @@ struct raid5_private_data {
struct list_head inactive_list;
wait_queue_head_t wait_for_stripe;
wait_queue_head_t wait_for_overlap;
+ wait_queue_head_t wait_for_block_op;
int inactive_blocked; /* release of inactive stripes blocked,
* waiting for 25% to be free
*/
--
1.3.0

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