[PATCH v3] async_tx: allow generic async_memcpy() not be effectedby channel switch

From: Dave Jiang
Date: Mon Apr 15 2013 - 19:40:21 EST

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This adds a generic async_memcpy() for the DMA engines that cannot do channel
switch. Previously it would exclude all DMA engines that don't have all equal
capabilities for all ops with the DMA_ASYNC_TX check. The RAID version of
async memcpy will only request RAID capable channels. This allow us to remove
the ifdef for channel switching fixup.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
crypto/async_tx/async_memcpy.c | 76 +++++++++++++++++++++++++++--------
crypto/async_tx/async_raid6_recov.c | 4 +-
drivers/md/raid5.c | 15 ++++---
include/linux/async_tx.h | 5 ++
include/linux/dmaengine.h | 4 --
5 files changed, 75 insertions(+), 29 deletions(-)

diff --git a/crypto/async_tx/async_memcpy.c b/crypto/async_tx/async_memcpy.c
index 9e62fef..3cecb49 100644
--- a/crypto/async_tx/async_memcpy.c
+++ b/crypto/async_tx/async_memcpy.c
@@ -30,24 +30,11 @@
#include <linux/dma-mapping.h>
#include <linux/async_tx.h>

-/**
- * async_memcpy - attempt to copy memory with a dma engine.
- * @dest: destination page
- * @src: src page
- * @dest_offset: offset into 'dest' to start transaction
- * @src_offset: offset into 'src' to start transaction
- * @len: length in bytes
- * @submit: submission / completion modifiers
- *
- * honored flags: ASYNC_TX_ACK
- */
-struct dma_async_tx_descriptor *
-async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
- unsigned int src_offset, size_t len,
- struct async_submit_ctl *submit)
+static struct dma_async_tx_descriptor *
+__async_memcpy(struct dma_chan *chan, struct page *dest, struct page *src,
+ unsigned int dest_offset, unsigned int src_offset, size_t len,
+ struct async_submit_ctl *submit)
{
- struct dma_chan *chan = async_tx_find_channel(submit, DMA_MEMCPY,
- &dest, 1, &src, 1, len);
struct dma_device *device = chan ? chan->device : NULL;
struct dma_async_tx_descriptor *tx = NULL;

@@ -98,8 +85,63 @@ async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,

return tx;
}
+
+/**
+ * async_memcpy - attempt to copy memory with a dma engine.
+ * @dest: destination page
+ * @src: src page
+ * @dest_offset: offset into 'dest' to start transaction
+ * @src_offset: offset into 'src' to start transaction
+ * @len: length in bytes
+ * @submit: submission / completion modifiers
+ *
+ * The function will grab any channel that has DMA_MEMCPY cap. This allows
+ * generic DMA memcpy without having to worry about channel switch issues.
+ */
+struct dma_async_tx_descriptor *
+async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
+ unsigned int src_offset, size_t len,
+ struct async_submit_ctl *submit)
+{
+ struct dma_chan *chan;
+ struct dma_async_tx_descriptor *depend_tx = submit->depend_tx;
+
+ if (depend_tx &&
+ dma_has_cap(DMA_MEMCPY, depend_tx->chan->device->cap_mask))
+ chan = depend_tx->chan;
+ else
+ chan = dma_find_channel(DMA_MEMCPY);
+
+ return __async_memcpy(chan, dest, src, dest_offset, src_offset,
+ len, submit);
+}
EXPORT_SYMBOL_GPL(async_memcpy);

+
+/**
+ * async_raid_memcpy - attempt to copy memory with a dma engine.
+ * @dest: destination page
+ * @src: src page
+ * @dest_offset: offset into 'dest' to start transaction
+ * @src_offset: offset into 'src' to start transaction
+ * @len: length in bytes
+ * @submit: submission / completion modifiers
+ *
+ * honored flags: ASYNC_TX_ACK
+ */
+struct dma_async_tx_descriptor *
+async_raid_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
+ unsigned int src_offset, size_t len,
+ struct async_submit_ctl *submit)
+{
+ struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR,
+ &dest, 1, &src, 1, len);
+
+ return __async_memcpy(chan, dest, src, dest_offset, src_offset,
+ len, submit);
+}
+EXPORT_SYMBOL_GPL(async_raid_memcpy);
+
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("asynchronous memcpy api");
MODULE_LICENSE("GPL");
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index a9f08a6..055cf63 100644
--- a/crypto/async_tx/async_raid6_recov.c
+++ b/crypto/async_tx/async_raid6_recov.c
@@ -208,7 +208,7 @@ __2data_recov_5(int disks, size_t bytes, int faila, int failb,
dq = blocks[failb];

init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
- tx = async_memcpy(dp, g, 0, 0, bytes, submit);
+ tx = async_raid_memcpy(dp, g, 0, 0, bytes, submit);
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);

@@ -464,7 +464,7 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,

init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
scribble);
- tx = async_memcpy(p, g, 0, 0, bytes, submit);
+ tx = async_raid_memcpy(p, g, 0, 0, bytes, submit);

init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
scribble);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 24909eb..8779266 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -760,10 +760,11 @@ async_copy_data(int frombio, struct bio *bio, struct page *page,
b_offset += bvl->bv_offset;
bio_page = bvl->bv_page;
if (frombio)
- tx = async_memcpy(page, bio_page, page_offset,
- b_offset, clen, &submit);
+ tx = async_raid_memcpy(page, bio_page,
+ page_offset, b_offset,
+ clen, &submit);
else
- tx = async_memcpy(bio_page, page, b_offset,
+ tx = async_raid_memcpy(bio_page, page, b_offset,
page_offset, clen, &submit);
}
/* chain the operations */
@@ -915,7 +916,8 @@ ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
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);
+ tx = async_raid_memcpy(xor_dest, xor_srcs[0], 0, 0,
+ STRIPE_SIZE, &submit);
else
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);

@@ -1302,7 +1304,8 @@ ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
to_addr_conv(sh, percpu));
if (unlikely(count == 1))
- tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
+ tx = async_raid_memcpy(xor_dest, xor_srcs[0], 0, 0,
+ STRIPE_SIZE, &submit);
else
tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
}
@@ -3211,7 +3214,7 @@ static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)

/* place all the copies on one channel */
init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
- tx = async_memcpy(sh2->dev[dd_idx].page,
+ tx = async_raid_memcpy(sh2->dev[dd_idx].page,
sh->dev[i].page, 0, 0, STRIPE_SIZE,
&submit);

diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index a1c486a..ce9be3d 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -183,6 +183,11 @@ async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
struct async_submit_ctl *submit);

struct dma_async_tx_descriptor *
+async_raid_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
+ unsigned int src_offset, size_t len,
+ struct async_submit_ctl *submit);
+
+struct dma_async_tx_descriptor *
async_memset(struct page *dest, int val, unsigned int offset,
size_t len, struct async_submit_ctl *submit);

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index dd6d21b..acd739c 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -820,11 +820,7 @@ static inline void net_dmaengine_put(void)
#ifdef CONFIG_ASYNC_TX_DMA
#define async_dmaengine_get() dmaengine_get()
#define async_dmaengine_put() dmaengine_put()
-#ifndef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
-#define async_dma_find_channel(type) dma_find_channel(DMA_ASYNC_TX)
-#else
#define async_dma_find_channel(type) dma_find_channel(type)
-#endif /* CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH */
#else
static inline void async_dmaengine_get(void)
{

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Next message: Stephen Rothwell: "Re: [PATCH 5/5] mm: Soft-dirty bits for user memory changestracking"
Previous message: Yasuaki Ishimatsu: "Re: [PATCH] firmware, memmap: fix firmware_map_entry leak"
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