From 5dd33c9a4c29015f6d87568d33521c98931a387e Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 16 Oct 2009 16:40:25 +1100 Subject: 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 --- crypto/async_tx/async_raid6_recov.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'crypto/async_tx/async_raid6_recov.c') diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c index 6d73dde4786d..8e30b6ed0789 100644 --- a/crypto/async_tx/async_raid6_recov.c +++ b/crypto/async_tx/async_raid6_recov.c @@ -263,10 +263,10 @@ __2data_recov_n(int disks, size_t bytes, int faila, int failb, * 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_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, 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_raid6_datap_recov(int disks, size_t bytes, int faila, 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 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila, * 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 -- cgit v1.2.3-55-g7522