[PATCH v5 10/16] md/raid5: add offset array in scribble buffer

Yufen Yu
2020-07-02T12:06:22Z

When enable shared buffers for stripe_head, it need an offset
array to record page offset to compute xor. To avoid repeatly allocate
an new array each time, we add a memory region into scribble buffer
to record offset.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
drivers/md/raid5.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 689a36c8e723..b14d5909f6a9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1477,6 +1477,15 @@ static addr_conv_t *to_addr_conv(struct stripe_head *sh,
return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
}

+/*
+ * Return a pointer to record offset address.
+ */
+static unsigned int *
+to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
+}
+
static struct dma_async_tx_descriptor *
ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
{
@@ -2360,8 +2369,9 @@ static int scribble_alloc(struct raid5_percpu *percpu,
int num, int cnt)
{
size_t obj_size =
- sizeof(struct page *) * (num+2) +
- sizeof(addr_conv_t) * (num+2);
+ sizeof(struct page *) * (num + 2) +
+ sizeof(addr_conv_t) * (num + 2) +
+ sizeof(unsigned int) * (num + 2);
void *scribble;

/*
--
2.25.4