dmaengine: add fence support
Some engines optimize operation by reading ahead in the descriptor chain
such that descriptor2 may start execution before descriptor1 completes.
If descriptor2 depends on the result from descriptor1 then a fence is
required (on descriptor2) to disable this optimization. The async_tx
api could implicitly identify dependencies via the 'depend_tx'
parameter, but that would constrain cases where the dependency chain
only specifies a completion order rather than a data dependency. So,
provide an ASYNC_TX_FENCE to explicitly identify data dependencies.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/crypto/async_tx/async_memcpy.c b/crypto/async_tx/async_memcpy.c
index 98e15bd..b38cbb3 100644
--- a/crypto/async_tx/async_memcpy.c
+++ b/crypto/async_tx/async_memcpy.c
@@ -52,9 +52,12 @@
if (device) {
dma_addr_t dma_dest, dma_src;
- unsigned long dma_prep_flags;
+ unsigned long dma_prep_flags = 0;
- dma_prep_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
+ if (submit->cb_fn)
+ dma_prep_flags |= DMA_PREP_INTERRUPT;
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_prep_flags |= DMA_PREP_FENCE;
dma_dest = dma_map_page(device->dev, dest, dest_offset, len,
DMA_FROM_DEVICE);
diff --git a/crypto/async_tx/async_memset.c b/crypto/async_tx/async_memset.c
index b896a6e..a374784 100644
--- a/crypto/async_tx/async_memset.c
+++ b/crypto/async_tx/async_memset.c
@@ -49,9 +49,12 @@
if (device) {
dma_addr_t dma_dest;
- unsigned long dma_prep_flags;
+ unsigned long dma_prep_flags = 0;
- dma_prep_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
+ if (submit->cb_fn)
+ dma_prep_flags |= DMA_PREP_INTERRUPT;
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_prep_flags |= DMA_PREP_FENCE;
dma_dest = dma_map_page(device->dev, dest, offset, len,
DMA_FROM_DEVICE);
diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 108b21e..a25e290 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -101,6 +101,7 @@
*/
if (src_cnt > pq_src_cnt) {
submit->flags &= ~ASYNC_TX_ACK;
+ submit->flags |= ASYNC_TX_FENCE;
dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP;
submit->cb_fn = NULL;
submit->cb_param = NULL;
@@ -111,6 +112,8 @@
if (cb_fn_orig)
dma_flags |= DMA_PREP_INTERRUPT;
}
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
/* Since we have clobbered the src_list we are committed
* to doing this asynchronously. Drivers force forward
@@ -282,6 +285,8 @@
dma_flags |= DMA_PREP_PQ_DISABLE_P;
if (!Q(blocks, disks))
dma_flags |= DMA_PREP_PQ_DISABLE_Q;
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
for (i = 0; i < disks; i++)
if (likely(blocks[i])) {
BUG_ON(is_raid6_zero_block(blocks[i]));
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index 0c14d48..822a42d 100644
--- a/crypto/async_tx/async_raid6_recov.c
+++ b/crypto/async_tx/async_raid6_recov.c
@@ -44,6 +44,8 @@
struct dma_async_tx_descriptor *tx;
enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
dma_src[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
dma_src[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
@@ -89,6 +91,8 @@
struct dma_async_tx_descriptor *tx;
enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
dma_src[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 1, &coef,
@@ -138,7 +142,7 @@
srcs[1] = q;
coef[0] = raid6_gfexi[failb-faila];
coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_sum_product(b, srcs, coef, bytes, submit);
/* Dy = P+Pxy+Dx */
@@ -188,23 +192,23 @@
dp = blocks[faila];
dq = blocks[failb];
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_memcpy(dp, g, 0, 0, bytes, submit);
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
/* compute P + Pxy */
srcs[0] = dp;
srcs[1] = p;
- init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
- scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
+ NULL, NULL, scribble);
tx = async_xor(dp, srcs, 0, 2, bytes, submit);
/* compute Q + Qxy */
srcs[0] = dq;
srcs[1] = q;
- init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
- scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
+ NULL, NULL, scribble);
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
@@ -212,7 +216,7 @@
srcs[1] = dq;
coef[0] = raid6_gfexi[failb-faila];
coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_sum_product(dq, srcs, coef, bytes, submit);
/* Dy = P+Pxy+Dx */
@@ -252,7 +256,7 @@
blocks[failb] = (void *)raid6_empty_zero_page;
blocks[disks-1] = dq;
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
/* Restore pointer table */
@@ -264,15 +268,15 @@
/* compute P + Pxy */
srcs[0] = dp;
srcs[1] = p;
- init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
- scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
+ NULL, NULL, scribble);
tx = async_xor(dp, srcs, 0, 2, bytes, submit);
/* compute Q + Qxy */
srcs[0] = dq;
srcs[1] = q;
- init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
- scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
+ NULL, NULL, scribble);
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
/* Dx = A*(P+Pxy) + B*(Q+Qxy) */
@@ -280,7 +284,7 @@
srcs[1] = dq;
coef[0] = raid6_gfexi[failb-faila];
coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_sum_product(dq, srcs, coef, bytes, submit);
/* Dy = P+Pxy+Dx */
@@ -407,13 +411,16 @@
int good = faila == 0 ? 1 : 0;
struct page *g = blocks[good];
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
+ scribble);
tx = async_memcpy(p, g, 0, 0, bytes, submit);
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
+ scribble);
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
} else {
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
+ scribble);
tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
}
@@ -426,11 +433,11 @@
srcs[0] = dq;
srcs[1] = q;
- init_async_submit(submit, ASYNC_TX_XOR_DROP_DST, tx, NULL, NULL,
- scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
+ NULL, NULL, scribble);
tx = async_xor(dq, srcs, 0, 2, bytes, submit);
- init_async_submit(submit, 0, tx, NULL, NULL, scribble);
+ init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_mult(dq, dq, coef, bytes, submit);
srcs[0] = p;
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index 56b5f98..db27987 100644
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -69,6 +69,7 @@
*/
if (src_cnt > xor_src_cnt) {
submit->flags &= ~ASYNC_TX_ACK;
+ submit->flags |= ASYNC_TX_FENCE;
dma_flags = DMA_COMPL_SKIP_DEST_UNMAP;
submit->cb_fn = NULL;
submit->cb_param = NULL;
@@ -78,7 +79,8 @@
}
if (submit->cb_fn)
dma_flags |= DMA_PREP_INTERRUPT;
-
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_flags |= DMA_PREP_FENCE;
/* Since we have clobbered the src_list we are committed
* to doing this asynchronously. Drivers force forward progress
* in case they can not provide a descriptor
@@ -264,12 +266,15 @@
dma_src = (dma_addr_t *) src_list;
if (dma_src && device && src_cnt <= device->max_xor) {
- unsigned long dma_prep_flags;
+ unsigned long dma_prep_flags = 0;
int i;
pr_debug("%s: (async) len: %zu\n", __func__, len);
- dma_prep_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
+ if (submit->cb_fn)
+ dma_prep_flags |= DMA_PREP_INTERRUPT;
+ if (submit->flags & ASYNC_TX_FENCE)
+ dma_prep_flags |= DMA_PREP_FENCE;
for (i = 0; i < src_cnt; i++)
dma_src[i] = dma_map_page(device->dev, src_list[i],
offset, len, DMA_TO_DEVICE);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0a5cf21..54ef8d7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -502,13 +502,17 @@
int i;
int page_offset;
struct async_submit_ctl submit;
+ enum async_tx_flags flags = 0;
if (bio->bi_sector >= sector)
page_offset = (signed)(bio->bi_sector - sector) * 512;
else
page_offset = (signed)(sector - bio->bi_sector) * -512;
- init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
+ if (frombio)
+ flags |= ASYNC_TX_FENCE;
+ init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
+
bio_for_each_segment(bvl, bio, i) {
int len = bio_iovec_idx(bio, i)->bv_len;
int clen;
@@ -685,7 +689,7 @@
atomic_inc(&sh->count);
- init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
ops_complete_compute, sh, to_addr_conv(sh, percpu));
if (unlikely(count == 1))
tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
@@ -763,7 +767,8 @@
count = set_syndrome_sources(blocks, sh);
blocks[count] = NULL; /* regenerating p is not necessary */
BUG_ON(blocks[count+1] != dest); /* q should already be set */
- init_async_submit(&submit, 0, NULL, ops_complete_compute, sh,
+ init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
+ ops_complete_compute, sh,
to_addr_conv(sh, percpu));
tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
} else {
@@ -775,8 +780,8 @@
blocks[count++] = sh->dev[i].page;
}
- init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
- ops_complete_compute, sh,
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
+ NULL, ops_complete_compute, sh,
to_addr_conv(sh, percpu));
tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
}
@@ -837,8 +842,9 @@
/* Q disk is one of the missing disks */
if (faila == syndrome_disks) {
/* Missing P+Q, just recompute */
- init_async_submit(&submit, 0, NULL, ops_complete_compute,
- sh, to_addr_conv(sh, percpu));
+ init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu));
return async_gen_syndrome(blocks, 0, count+2,
STRIPE_SIZE, &submit);
} else {
@@ -859,21 +865,24 @@
blocks[count++] = sh->dev[i].page;
}
dest = sh->dev[data_target].page;
- init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
- NULL, NULL, to_addr_conv(sh, percpu));
+ init_async_submit(&submit,
+ ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
+ NULL, NULL, NULL,
+ to_addr_conv(sh, percpu));
tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
&submit);
count = set_syndrome_sources(blocks, sh);
- init_async_submit(&submit, 0, tx, ops_complete_compute,
- sh, to_addr_conv(sh, percpu));
+ init_async_submit(&submit, ASYNC_TX_FENCE, tx,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu));
return async_gen_syndrome(blocks, 0, count+2,
STRIPE_SIZE, &submit);
}
}
- init_async_submit(&submit, 0, NULL, ops_complete_compute, sh,
- to_addr_conv(sh, percpu));
+ init_async_submit(&submit, ASYNC_TX_FENCE, NULL, ops_complete_compute,
+ sh, to_addr_conv(sh, percpu));
if (failb == syndrome_disks) {
/* We're missing D+P. */
return async_raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE,
@@ -916,7 +925,7 @@
xor_srcs[count++] = dev->page;
}
- init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST, tx,
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
ops_complete_prexor, sh, to_addr_conv(sh, percpu));
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index 866e61c..a1c486a 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -58,11 +58,14 @@
* array.
* @ASYNC_TX_ACK: immediately ack the descriptor, precludes setting up a
* dependency chain
+ * @ASYNC_TX_FENCE: specify that the next operation in the dependency
+ * chain uses this operation's result as an input
*/
enum async_tx_flags {
ASYNC_TX_XOR_ZERO_DST = (1 << 0),
ASYNC_TX_XOR_DROP_DST = (1 << 1),
ASYNC_TX_ACK = (1 << 2),
+ ASYNC_TX_FENCE = (1 << 3),
};
/**
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 1012f1a..4d6c1c9 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -87,6 +87,8 @@
* @DMA_PREP_CONTINUE - indicate to a driver that it is reusing buffers as
* sources that were the result of a previous operation, in the case of a PQ
* operation it continues the calculation with new sources
+ * @DMA_PREP_FENCE - tell the driver that subsequent operations depend
+ * on the result of this operation
*/
enum dma_ctrl_flags {
DMA_PREP_INTERRUPT = (1 << 0),
@@ -98,6 +100,7 @@
DMA_PREP_PQ_DISABLE_P = (1 << 6),
DMA_PREP_PQ_DISABLE_Q = (1 << 7),
DMA_PREP_CONTINUE = (1 << 8),
+ DMA_PREP_FENCE = (1 << 9),
};
/**