path: root/Documentation/crypto
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authorDan Williams <dan.j.williams@intel.com>2009-07-14 12:20:37 -0700
committerDan Williams <dan.j.williams@intel.com>2009-08-29 19:09:27 -0700
commit0a82a6239beecc95db6e05fe43ee62d16b381d38 (patch)
tree524f6417ae8128f5b1da322872e860bd4af5840d /Documentation/crypto
parentb2f46fd8ef3dff2ab30f31126833f78b7480283a (diff)
async_tx: add support for asynchronous RAID6 recovery operations
async_raid6_2data_recov() recovers two data disk failures async_raid6_datap_recov() recovers a data disk and the P disk These routines are a port of the synchronous versions found in drivers/md/raid6recov.c. The primary difference is breaking out the xor operations into separate calls to async_xor. Two helper routines are introduced to perform scalar multiplication where needed. async_sum_product() multiplies two sources by scalar coefficients and then sums (xor) the result. async_mult() simply multiplies a single source by a scalar. This implemention also includes, in contrast to the original synchronous-only code, special case handling for the 4-disk and 5-disk array cases. In these situations the default N-disk algorithm will present 0-source or 1-source operations to dma devices. To cover for dma devices where the minimum source count is 2 we implement 4-disk and 5-disk handling in the recovery code. [ Impact: asynchronous raid6 recovery routines for 2data and datap cases ] Cc: Yuri Tikhonov <yur@emcraft.com> Cc: Ilya Yanok <yanok@emcraft.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'Documentation/crypto')
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/crypto/async-tx-api.txt b/Documentation/crypto/async-tx-api.txt
index 0e48e054d69a..ba046b8fa92f 100644
--- a/Documentation/crypto/async-tx-api.txt
+++ b/Documentation/crypto/async-tx-api.txt
@@ -67,6 +67,10 @@ xor_val - xor a series of source buffers and set a flag if the
pq - generate the p+q (raid6 syndrome) from a series of source buffers
pq_val - validate that a p and or q buffer are in sync with a given series of
+datap - (raid6_datap_recov) recover a raid6 data block and the p block
+ from the given sources
+2data - (raid6_2data_recov) recover 2 raid6 data blocks from the given
+ sources
3.3 Descriptor management:
The return value is non-NULL and points to a 'descriptor' when the operation

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