md/async: don't pass a memory pointer as a page pointer.
md/raid6 passes a list of 'struct page *' to the async_tx routines,
which then either DMA map them for offload, or take the page_address
for CPU based calculations.
For RAID6 we sometime leave 'blanks' in the list of pages.
For CPU based calcs, we want to treat theses as a page of zeros.
For offloaded calculations, we simply don't pass a page to the
hardware.
Currently the 'blanks' are encoded as a pointer to
raid6_empty_zero_page. This is a 4096 byte memory region, not a
'struct page'. This is mostly handled correctly but is rather ugly.
So change the code to pass and expect a NULL pointer for the blanks.
When taking page_address of a page, we need to check for a NULL and
in that case use raid6_empty_zero_page.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index 6d73dde..8e30b6e 100644
--- a/crypto/async_tx/async_raid6_recov.c
+++ b/crypto/async_tx/async_raid6_recov.c
@@ -263,10 +263,10 @@
* delta p and delta q
*/
dp = blocks[faila];
- blocks[faila] = (void *)raid6_empty_zero_page;
+ blocks[faila] = NULL;
blocks[disks-2] = dp;
dq = blocks[failb];
- blocks[failb] = (void *)raid6_empty_zero_page;
+ blocks[failb] = NULL;
blocks[disks-1] = dq;
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
@@ -338,7 +338,10 @@
async_tx_quiesce(&submit->depend_tx);
for (i = 0; i < disks; i++)
- ptrs[i] = page_address(blocks[i]);
+ if (blocks[i] == NULL)
+ ptrs[i] = (void*)raid6_empty_zero_page;
+ else
+ ptrs[i] = page_address(blocks[i]);
raid6_2data_recov(disks, bytes, faila, failb, ptrs);
@@ -398,7 +401,10 @@
async_tx_quiesce(&submit->depend_tx);
for (i = 0; i < disks; i++)
- ptrs[i] = page_address(blocks[i]);
+ if (blocks[i] == NULL)
+ ptrs[i] = (void*)raid6_empty_zero_page;
+ else
+ ptrs[i] = page_address(blocks[i]);
raid6_datap_recov(disks, bytes, faila, ptrs);
@@ -414,7 +420,7 @@
* Use the dead data page as temporary storage for delta q
*/
dq = blocks[faila];
- blocks[faila] = (void *)raid6_empty_zero_page;
+ blocks[faila] = NULL;
blocks[disks-1] = dq;
/* in the 4 disk case we only need to perform a single source