[PATCH v5 09/16] md/raid5: add new xor function to support different page offset

Yufen Yu
2020-07-02T12:06:21Z

RAID5 will call async_xor() and async_xor_val() to compute xor.
However, both of them require common src/dst page offset. After
introducing shared pages of r5pages, we want these xor computer
function to support different src/dst page offset.

Here, we add two new functions async_xor_offsets() and
async_xor_val_offsets() respectively for async_xor() and async_xor_val().

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
crypto/async_tx/async_xor.c | 120 +++++++++++++++++++++++++++++++-----
include/linux/async_tx.h | 11 ++++
2 files changed, 114 insertions(+), 17 deletions(-)

diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index 4e5eebe52e6a..f5666ac84d34 100644
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -97,7 +97,8 @@ do_async_xor(struct dma_chan *chan, struct dmaengine_unmap_data *unmap,
}

static void
-do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
+do_sync_xor_offsets(struct page *dest, unsigned int offset,
+ struct page **src_list, unsigned int *src_offset,
int src_cnt, size_t len, struct async_submit_ctl *submit)
{
int i;
@@ -114,7 +115,8 @@ do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
/* convert to buffer pointers */
for (i = 0; i < src_cnt; i++)
if (src_list[i])
- srcs[xor_src_cnt++] = page_address(src_list[i]) + offset;
+ srcs[xor_src_cnt++] = page_address(src_list[i]) +
+ (src_offset ? src_offset[i] : offset);
src_cnt = xor_src_cnt;
/* set destination address */
dest_buf = page_address(dest) + offset;
@@ -135,11 +137,31 @@ do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
async_tx_sync_epilog(submit);
}

+static inline bool
+dma_xor_aligned_offsets(struct dma_device *device, unsigned int offset,
+ unsigned int *src_offset, int src_cnt, int len)
+{
+ int i;
+
+ if (!is_dma_xor_aligned(device, offset, 0, len))
+ return false;
+
+ if (!src_offset)
+ return true;
+
+ for (i = 0; i < src_cnt; i++) {
+ if (!is_dma_xor_aligned(device, src_offset[i], 0, len))
+ return false;
+ }
+ return true;
+}
+
/**
- * async_xor - attempt to xor a set of blocks with a dma engine.
+ * async_xor_offsets - attempt to xor a set of blocks with a dma engine.
* @dest: destination page
+ * @offset: dst offset to start transaction
* @src_list: array of source pages
- * @offset: common src/dst offset to start transaction
+ * @src_offset: array of source pages offset, NULL means common src/dst offset
* @src_cnt: number of source pages
* @len: length in bytes
* @submit: submission / completion modifiers
@@ -157,8 +179,9 @@ do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
* is not specified.
*/
struct dma_async_tx_descriptor *
-async_xor(struct page *dest, struct page **src_list, unsigned int offset,
- int src_cnt, size_t len, struct async_submit_ctl *submit)
+async_xor_offsets(struct page *dest, unsigned int offset,
+ struct page **src_list, unsigned int *src_offset,
+ int src_cnt, size_t len, struct async_submit_ctl *submit)
{
struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR,
&dest, 1, src_list,
@@ -171,7 +194,8 @@ async_xor(struct page *dest, struct page **src_list, unsigned int offset,
if (device)
unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOWAIT);

- if (unmap && is_dma_xor_aligned(device, offset, 0, len)) {
+ if (unmap && dma_xor_aligned_offsets(device, offset,
+ src_offset, src_cnt, len)) {
struct dma_async_tx_descriptor *tx;
int i, j;

@@ -184,7 +208,8 @@ async_xor(struct page *dest, struct page **src_list, unsigned int offset,
continue;
unmap->to_cnt++;
unmap->addr[j++] = dma_map_page(device->dev, src_list[i],
- offset, len, DMA_TO_DEVICE);
+ src_offset ? src_offset[i] : offset,
+ len, DMA_TO_DEVICE);
}

/* map it bidirectional as it may be re-used as a source */
@@ -213,11 +238,42 @@ async_xor(struct page *dest, struct page **src_list, unsigned int offset,
/* wait for any prerequisite operations */
async_tx_quiesce(&submit->depend_tx);

- do_sync_xor(dest, src_list, offset, src_cnt, len, submit);
+ do_sync_xor_offsets(dest, offset, src_list, src_offset,
+ src_cnt, len, submit);

return NULL;
}
}
+EXPORT_SYMBOL_GPL(async_xor_offsets);
+
+/**
+ * async_xor - attempt to xor a set of blocks with a dma engine.
+ * @dest: destination page
+ * @src_list: array of source pages
+ * @offset: common src/dst offset to start transaction
+ * @src_cnt: number of source pages
+ * @len: length in bytes
+ * @submit: submission / completion modifiers
+ *
+ * honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST
+ *
+ * xor_blocks always uses the dest as a source so the
+ * ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in
+ * the calculation. The assumption with dma eninges is that they only
+ * use the destination buffer as a source when it is explicity specified
+ * in the source list.
+ *
+ * src_list note: if the dest is also a source it must be at index zero.
+ * The contents of this array will be overwritten if a scribble region
+ * is not specified.
+ */
+struct dma_async_tx_descriptor *
+async_xor(struct page *dest, struct page **src_list, unsigned int offset,
+ int src_cnt, size_t len, struct async_submit_ctl *submit)
+{
+ return async_xor_offsets(dest, offset, src_list, NULL,
+ src_cnt, len, submit);
+}
EXPORT_SYMBOL_GPL(async_xor);

static int page_is_zero(struct page *p, unsigned int offset, size_t len)
@@ -237,10 +293,11 @@ xor_val_chan(struct async_submit_ctl *submit, struct page *dest,
}

/**
- * async_xor_val - attempt a xor parity check with a dma engine.
+ * async_xor_val_offsets - attempt a xor parity check with a dma engine.
* @dest: destination page used if the xor is performed synchronously
+ * @offset: des offset in pages to start transaction
* @src_list: array of source pages
- * @offset: offset in pages to start transaction
+ * @src_offset: array of source pages offset, NULL means common src/det offset
* @src_cnt: number of source pages
* @len: length in bytes
* @result: 0 if sum == 0 else non-zero
@@ -253,9 +310,10 @@ xor_val_chan(struct async_submit_ctl *submit, struct page *dest,
* is not specified.
*/
struct dma_async_tx_descriptor *
-async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
- int src_cnt, size_t len, enum sum_check_flags *result,
- struct async_submit_ctl *submit)
+async_xor_val_offsets(struct page *dest, unsigned int offset,
+ struct page **src_list, unsigned int *src_offset,
+ int src_cnt, size_t len, enum sum_check_flags *result,
+ struct async_submit_ctl *submit)
{
struct dma_chan *chan = xor_val_chan(submit, dest, src_list, src_cnt, len);
struct dma_device *device = chan ? chan->device : NULL;
@@ -268,7 +326,7 @@ async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOWAIT);

if (unmap && src_cnt <= device->max_xor &&
- is_dma_xor_aligned(device, offset, 0, len)) {
+ dma_xor_aligned_offsets(device, offset, src_offset, src_cnt, len)) {
unsigned long dma_prep_flags = 0;
int i;

@@ -281,7 +339,8 @@ async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,

for (i = 0; i < src_cnt; i++) {
unmap->addr[i] = dma_map_page(device->dev, src_list[i],
- offset, len, DMA_TO_DEVICE);
+ src_offset ? src_offset[i] : offset,
+ len, DMA_TO_DEVICE);
unmap->to_cnt++;
}
unmap->len = len;
@@ -312,7 +371,8 @@ async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
submit->flags |= ASYNC_TX_XOR_DROP_DST;
submit->flags &= ~ASYNC_TX_ACK;

- tx = async_xor(dest, src_list, offset, src_cnt, len, submit);
+ tx = async_xor_offsets(dest, offset, src_list, src_offset,
+ src_cnt, len, submit);

async_tx_quiesce(&tx);

@@ -325,6 +385,32 @@ async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,

return tx;
}
+EXPORT_SYMBOL_GPL(async_xor_val_offsets);
+
+/**
+ * async_xor_val - attempt a xor parity check with a dma engine.
+ * @dest: destination page used if the xor is performed synchronously
+ * @src_list: array of source pages
+ * @offset: offset in pages to start transaction
+ * @src_cnt: number of source pages
+ * @len: length in bytes
+ * @result: 0 if sum == 0 else non-zero
+ * @submit: submission / completion modifiers
+ *
+ * honored flags: ASYNC_TX_ACK
+ *
+ * src_list note: if the dest is also a source it must be at index zero.
+ * The contents of this array will be overwritten if a scribble region
+ * is not specified.
+ */
+struct dma_async_tx_descriptor *
+async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
+ int src_cnt, size_t len, enum sum_check_flags *result,
+ struct async_submit_ctl *submit)
+{
+ return async_xor_val_offsets(dest, offset, src_list, NULL, src_cnt,
+ len, result, submit);
+}
EXPORT_SYMBOL_GPL(async_xor_val);

MODULE_AUTHOR("Intel Corporation");
diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index 75e582b8d2d9..8d79e2de06bd 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -162,11 +162,22 @@ struct dma_async_tx_descriptor *
async_xor(struct page *dest, struct page **src_list, unsigned int offset,
int src_cnt, size_t len, struct async_submit_ctl *submit);

+struct dma_async_tx_descriptor *
+async_xor_offsets(struct page *dest, unsigned int offset,
+ struct page **src_list, unsigned int *src_offset,
+ int src_cnt, size_t len, struct async_submit_ctl *submit);
+
struct dma_async_tx_descriptor *
async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
int src_cnt, size_t len, enum sum_check_flags *result,
struct async_submit_ctl *submit);

+struct dma_async_tx_descriptor *
+async_xor_val_offsets(struct page *dest, unsigned int offset,
+ struct page **src_list, unsigned int *src_offset,
+ int src_cnt, size_t len, enum sum_check_flags *result,
+ struct async_submit_ctl *submit);
+
struct dma_async_tx_descriptor *
async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
unsigned int src_offset, size_t len,
--
2.25.4