aboutsummaryrefslogtreecommitdiff
path: root/Documentation/crypto
AgeCommit message (Collapse)Author
2009-08-29async_tx: add support for asynchronous RAID6 recovery operationsDan Williams
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>
2009-08-29async_tx: add support for asynchronous GF multiplicationDan Williams
[ Based on an original patch by Yuri Tikhonov ] This adds support for doing asynchronous GF multiplication by adding two additional functions to the async_tx API: async_gen_syndrome() does simultaneous XOR and Galois field multiplication of sources. async_syndrome_val() validates the given source buffers against known P and Q values. When a request is made to run async_pq against more than the hardware maximum number of supported sources we need to reuse the previous generated P and Q values as sources into the next operation. Care must be taken to remove Q from P' and P from Q'. For example to perform a 5 source pq op with hardware that only supports 4 sources at a time the following approach is taken: p, q = PQ(src0, src1, src2, src3, COEF({01}, {02}, {04}, {08})) p', q' = PQ(p, q, q, src4, COEF({00}, {01}, {00}, {10})) p' = p + q + q + src4 = p + src4 q' = {00}*p + {01}*q + {00}*q + {10}*src4 = q + {10}*src4 Note: 4 is the minimum acceptable maxpq otherwise we punt to synchronous-software path. The DMA_PREP_CONTINUE flag indicates to the driver to reuse p and q as sources (in the above manner) and fill the remaining slots up to maxpq with the new sources/coefficients. Note1: Some devices have native support for P+Q continuation and can skip this extra work. Devices with this capability can advertise it with dma_set_maxpq. It is up to each driver how to handle the DMA_PREP_CONTINUE flag. Note2: The api supports disabling the generation of P when generating Q, this is ignored by the synchronous path but is implemented by some dma devices to save unnecessary writes. In this case the continuation algorithm is simplified to only reuse Q as a source. Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Ilya Yanok <yanok@emcraft.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>
2009-06-03async_xor: permit callers to pass in a 'dma/page scribble' regionDan Williams
async_xor() needs space to perform dma and page address conversions. In most cases the code can simply reuse the struct page * array because the size of the native pointer matches the size of a dma/page address. In order to support archs where sizeof(dma_addr_t) is larger than sizeof(struct page *), or to preserve the input parameters, we utilize a memory region passed in by the caller. Since the code is now prepared to handle the case where it cannot perform address conversions on the stack, we no longer need the !HIGHMEM64G dependency in drivers/dma/Kconfig. [ Impact: don't clobber input buffers for address conversions ] 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>
2009-06-03async_tx: structify submission arguments, add scribbleDan Williams
Prepare the api for the arrival of a new parameter, 'scribble'. This will allow callers to identify scratchpad memory for dma address or page address conversions. As this adds yet another parameter, take this opportunity to convert the common submission parameters (flags, dependency, callback, and callback argument) into an object that is passed by reference. Also, take this opportunity to fix up the kerneldoc and add notes about the relevant ASYNC_TX_* flags for each routine. [ Impact: moves api pass-by-value parameters to a pass-by-reference struct ] Signed-off-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-06-03async_tx: kill ASYNC_TX_DEP_ACK flagDan Williams
In support of inter-channel chaining async_tx utilizes an ack flag to gate whether a dependent operation can be chained to another. While the flag is not set the chain can be considered open for appending. Setting the ack flag closes the chain and flags the descriptor for garbage collection. The ASYNC_TX_DEP_ACK flag essentially means "close the chain after adding this dependency". Since each operation can only have one child the api now implicitly sets the ack flag at dependency submission time. This removes an unnecessary management burden from clients of the api. [ Impact: clean up and enforce one dependency per operation ] 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>
2009-04-08async_tx: rename zero_sum to valDan Williams
'zero_sum' does not properly describe the operation of generating parity and checking that it validates against an existing buffer. Change the name of the operation to 'val' (for 'validate'). This is in anticipation of the p+q case where it is a requirement to identify the target parity buffers separately from the source buffers, because the target parity buffers will not have corresponding pq coefficients. 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>
2009-01-05async_tx, dmaengine: document channel allocation and api reworkDan Williams
"Wouldn't it be better if the dmaengine layer made sure it didn't pass the same channel several times to a client? I mean, you seem concerned that the memcpy() API should be transparent and easy to use, but the whole registration interface is just ridiculously complicated..." - Haavard The dmaengine and async_tx registration/allocation interface is indeed needlessly complicated. This redesign has the following goals: 1/ Simplify reference counting: dma channels are not something one would expect to be hotplugged, it should be an exceptional event handled by drivers not something clients should be mandated to handle in a callback. The common case channel removal event is 'rmmod <dma driver>', which for simplicity should be disallowed if the channel is in use. 2/ Add an interface for requesting exclusive access to a channel suitable to device-to-memory users. 3/ Convert all memory-to-memory users over to a common allocator, the goal here is to not have competing channel allocation schemes. The only competition should be between device-to-memory exclusive allocations and the memory-to-memory usage case where channels are shared between multiple "clients". Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Cc: Neil Brown <neilb@suse.de> Cc: Jeff Garzik <jeff@garzik.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-01-11[CRYPTO] doc: Update api-intro.txtHerbert Xu
This patch updates the list of transforms we support and clarifies that the Block Ciphers interface in fact supports all ciphers including stream ciphers. It also removes the obsolete Configuration Notes section and adds the linux-crypto mailing list as the primary bug reporting address. Finally it documents the fact that setkey should only be called from user context. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-09-24async_tx: usage documentation and developer notes (v2)Dan Williams
Changes in v2: * cleanups from Randy and Shannon Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com> Reviewed-by: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2007-05-09documentation: convert the Documentation directory to UTF-8John Anthony Kazos Jr
Convert files within the Documentation directory to UTF-8. Adrian Bunk: small additional fixes Signed-off-by: John Anthony Kazos Jr. <jakj@j-a-k-j.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2007-03-21[CRYPTO] doc: Fix typo in hash exampleJohannes Schlumberger
there is a tiny bug in Documentation/crypto/api-intro.txt. The file has the following example code: struct scatterlist sg[2]; [...] if (crypto_hash_digest(&desc, &sg, 2, result)) which does not match the declaration of crypto_hash_digest() in include/linux/crypto.h. (static inline int crypto_hash_digest(struct hash_desc *desc, struct scatterlist *sg, unsigned int nbytes, u8 *out) The code in the example passes the address of a pointer (an array actually) as the second argument, while the function expects the pointer itself. I have attached a patch to fix this. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-02-07[CRYPTO] doc: added the developer of Camellia cipherNoriaki TAKAMIYA
This patch adds the developer of Camellia cipher algorithm. Signed-off-by: Noriaki TAKAMIYA <takamiya@po.ntts.co.jp> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2006-09-21[CRYPTO] doc: Update documentation for hash and meHerbert Xu
This patch updates the documentation to reflect the switch from digest to hash. It also replaces notes about emailing James Morris to refer to me instead. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2005-09-10[PATCH] Spelling fixes for Documentation/Tobias Klauser
The attached patch fixes the following spelling errors in Documentation/ - double "the" - Several misspellings of function/functionality - infomation - memeory - Recieved - wether and possibly others which I forgot ;-) Trailing whitespaces on the same line as the typo are also deleted. Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch> Signed-off-by: Domen Puncer <domen@coderock.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-01[CRYPTO]: Fix XTEA implementationAaron Grothe
The XTEA implementation was incorrect due to a misinterpretation of operator precedence. Because of the wide-spread nature of this error, the erroneous implementation will be kept, albeit under the new name of XETA. Signed-off-by: Aaron Grothe <ajgrothe@yahoo.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!