Because kernel_fpu_begin() and kernel_fpu_end() operations are too
slow, the performance gain of general mode implementation + aes-aesni
is almost all compensated.
The AES-NI support for more modes are implemented as follow:
- Add a new AES algorithm implementation named __aes-aesni without
kernel_fpu_begin/end()
- Use fpu(<mode>(AES)) to provide kenrel_fpu_begin/end() invoking
- Add <mode>(AES) ablkcipher, which uses cryptd(fpu(<mode>(AES))) to
defer cryption to cryptd context in soft_irq context.
Now the ctr, lrw, pcbc and xts support are added.
Performance testing based on dm-crypt shows that cryption time can be
reduced to 50% of general mode implementation + aes-aesni implementation.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Blkcipher touching FPU need to be enclosed by kernel_fpu_begin() and
kernel_fpu_end(). If they are invoked in cipher algorithm
implementation, they will be invoked for each block, so that
performance will be hurt, because they are "slow" operations. This
patch implements "fpu" template, which makes these operations to be
invoked for each request.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Use crypto_alloc_base() instead of crypto_alloc_ablkcipher() to
allocate underlying tfm in cryptd_alloc_ablkcipher. Because
crypto_alloc_ablkcipher() prefer GENIV encapsulated crypto instead of
raw one, while cryptd_alloc_ablkcipher needed the raw one.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Use kzfree() instead of memset() + kfree().
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Applying kernel janitors todos (printk calls need KERN_*
constants on linebeginnings, reduce stack footprint where
possible) to tcrypts test_hash_speed (where stacks
memory footprint was very high (on i386 1184 bytes to
160 now).
Signed-off-by: Frank Seidel <frank@f-seidel.de>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
A quirk that we've always supported is having an sg entry that's
bigger than a page, or more generally an sg entry that crosses
page boundaries. Even though it would be better to explicitly have
to sg entries for this, we need to support it for the existing users,
in particular, IPsec.
The new ahash sg walking code did try to handle this, but there was
a bug where we didn't increment the page so kept on walking on the
first page over an dover again.
This patch fixes it.
Tested-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: padlock - Revert aes-all alias to aes
crypto: api - Fix algorithm module auto-loading
crypto: eseqiv - Fix IV generation for sync algorithms
crypto: ixp4xx - check firmware for crypto support
The commit a760a6656e (crypto:
api - Fix module load deadlock with fallback algorithms) broke
the auto-loading of algorithms that require fallbacks. The
problem is that the fallback mask check is missing an and which
cauess bits that should be considered to interfere with the
result.
Reported-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
If crypto_ablkcipher_encrypt() returns synchronous,
eseqiv_complete2() is called even if req->giv is already the
pointer to the generated IV. The generated IV is overwritten
with some random data in this case. This patch fixes this by
calling eseqiv_complete2() just if the generated IV has to be
copied to req->giv.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx:
dma: Add SoF and EoF debugging to ipu_idmac.c, minor cleanup
dw_dmac: add cyclic API to DW DMA driver
dmaengine: Add privatecnt to revert DMA_PRIVATE property
dmatest: add dma interrupts and callbacks
dmatest: add xor test
dmaengine: allow dma support for async_tx to be toggled
async_tx: provide __async_inline for HAS_DMA=n archs
dmaengine: kill some unused headers
dmaengine: initialize tx_list in dma_async_tx_descriptor_init
dma: i.MX31 IPU DMA robustness improvements
dma: improve section assignment in i.MX31 IPU DMA driver
dma: ipu_idmac driver cosmetic clean-up
dmaengine: fail device registration if channel registration fails
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: ixp4xx - Fix handling of chained sg buffers
crypto: shash - Fix unaligned calculation with short length
hwrng: timeriomem - Use phys address rather than virt
* 'for-linus' of git://neil.brown.name/md: (53 commits)
md/raid5 revise rules for when to update metadata during reshape
md/raid5: minor code cleanups in make_request.
md: remove CONFIG_MD_RAID_RESHAPE config option.
md/raid5: be more careful about write ordering when reshaping.
md: don't display meaningless values in sysfs files resync_start and sync_speed
md/raid5: allow layout and chunksize to be changed on active array.
md/raid5: reshape using largest of old and new chunk size
md/raid5: prepare for allowing reshape to change layout
md/raid5: prepare for allowing reshape to change chunksize.
md/raid5: clearly differentiate 'before' and 'after' stripes during reshape.
Documentation/md.txt update
md: allow number of drives in raid5 to be reduced
md/raid5: change reshape-progress measurement to cope with reshaping backwards.
md: add explicit method to signal the end of a reshape.
md/raid5: enhance raid5_size to work correctly with negative delta_disks
md/raid5: drop qd_idx from r6_state
md/raid6: move raid6 data processing to raid6_pq.ko
md: raid5 run(): Fix max_degraded for raid level 4.
md: 'array_size' sysfs attribute
md: centralize ->array_sectors modifications
...
This makes the includes more explicit, and is preparation for moving
md_k.h to drivers/md/md.h
Remove include/raid/md.h as its only remaining use was to #include
other files.
Signed-off-by: NeilBrown <neilb@suse.de>
When the total length is shorter than the calculated number of unaligned bytes, the call to shash->update breaks. For example, calling crc32c on unaligned buffer with length of 1 can result in a system crash.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (29 commits)
crypto: sha512-s390 - Add missing block size
hwrng: timeriomem - Breaks an allyesconfig build on s390:
nlattr: Fix build error with NET off
crypto: testmgr - add zlib test
crypto: zlib - New zlib crypto module, using pcomp
crypto: testmgr - Add support for the pcomp interface
crypto: compress - Add pcomp interface
netlink: Move netlink attribute parsing support to lib
crypto: Fix dead links
hwrng: timeriomem - New driver
crypto: chainiv - Use kcrypto_wq instead of keventd_wq
crypto: cryptd - Per-CPU thread implementation based on kcrypto_wq
crypto: api - Use dedicated workqueue for crypto subsystem
crypto: testmgr - Test skciphers with no IVs
crypto: aead - Avoid infinite loop when nivaead fails selftest
crypto: skcipher - Avoid infinite loop when cipher fails selftest
crypto: api - Fix crypto_alloc_tfm/create_create_tfm return convention
crypto: api - crypto_alg_mod_lookup either tested or untested
crypto: amcc - Add crypt4xx driver
crypto: ansi_cprng - Add maintainer
...
To allow an async_tx routine to be compiled away on HAS_DMA=n arch it
needs to be declared __always_inline otherwise the compiler may emit
code and cause a link error.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The current "comp" crypto interface supports one-shot (de)compression only,
i.e. the whole data buffer to be (de)compressed must be passed at once, and
the whole (de)compressed data buffer will be received at once.
In several use-cases (e.g. compressed file systems that store files in big
compressed blocks), this workflow is not suitable.
Furthermore, the "comp" type doesn't provide for the configuration of
(de)compression parameters, and always allocates workspace memory for both
compression and decompression, which may waste memory.
To solve this, add a "pcomp" partial (de)compression interface that provides
the following operations:
- crypto_compress_{init,update,final}() for compression,
- crypto_decompress_{init,update,final}() for decompression,
- crypto_{,de}compress_setup(), to configure (de)compression parameters
(incl. allocating workspace memory).
The (de)compression methods take a struct comp_request, which was mimicked
after the z_stream object in zlib, and contains buffer pointer and length
pairs for input and output.
The setup methods take an opaque parameter pointer and length pair. Parameters
are supposed to be encoded using netlink attributes, whose meanings depend on
the actual (name of the) (de)compression algorithm.
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
With the mandatory algorithm testing at registration, we have
now created a deadlock with algorithms requiring fallbacks.
This can happen if the module containing the algorithm requiring
fallback is loaded first, without the fallback module being loaded
first. The system will then try to test the new algorithm, find
that it needs to load a fallback, and then try to load that.
As both algorithms share the same module alias, it can attempt
to load the original algorithm again and block indefinitely.
As algorithms requiring fallbacks are a special case, we can fix
this by giving them a different module alias than the rest. Then
it's just a matter of using the right aliases according to what
algorithms we're trying to find.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
crypto_ahash_show changed to use cra_ahash for digestsize reference.
Signed-off-by: Lee Nipper <lee.nipper@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
keventd_wq has potential starvation problem, so use dedicated
kcrypto_wq instead.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Use dedicated workqueue for crypto subsystem
A dedicated workqueue named kcrypto_wq is created to be used by crypto
subsystem. The system shared keventd_wq is not suitable for
encryption/decryption, because of potential starvation problem.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As it is an skcipher with no IV escapes testing altogether because
we only test givcipher objects. This patch fixes the bypass logic
to test these algorithms.
Conversely, we're currently testing nivaead algorithms with IVs,
which would have deadlocked had it not been for the fact that no
nivaead algorithms have any test vectors. This patch also fixes
that case.
Both fixes are ugly as hell, but this ugliness should hopefully
disappear once we move them into the per-type code (i.e., the
AEAD test would live in aead.c and the skcipher stuff in ablkcipher.c).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When an aead constructed through crypto_nivaead_default fails
its selftest, we'll loop forever trying to construct new aead
objects but failing because it already exists.
The crux of the issue is that once an aead fails the selftest,
we'll ignore it on the next run through crypto_aead_lookup and
attempt to construct a new aead.
We should instead return an error to the caller if we find an
an that has failed the test.
This bug hasn't manifested itself yet because we don't have any
test vectors for the existing nivaead algorithms. They're tested
through the underlying algorithms only.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When an skcipher constructed through crypto_givcipher_default fails
its selftest, we'll loop forever trying to construct new skcipher
objects but failing because it already exists.
The crux of the issue is that once a givcipher fails the selftest,
we'll ignore it on the next run through crypto_skcipher_lookup and
attempt to construct a new givcipher.
We should instead return an error to the caller if we find a
givcipher that has failed the test.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This is based on a report and patch by Geert Uytterhoeven.
The functions crypto_alloc_tfm and create_create_tfm return a
pointer that needs to be adjusted by the caller when successful
and otherwise an error value. This means that the caller has
to check for the error and only perform the adjustment if the
pointer returned is valid.
Since all callers want to make the adjustment and we know how
to adjust it ourselves, it's much easier to just return adjusted
pointer directly.
The only caveat is that we have to return a void * instead of
struct crypto_tfm *. However, this isn't that bad because both
of these functions are for internal use only (by types code like
shash.c, not even algorithms code).
This patch also moves crypto_alloc_tfm into crypto/internal.h
(crypto_create_tfm is already there) to reflect this.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As it stands crypto_alg_mod_lookup will search either tested or
untested algorithms, but never both at the same time. However,
we need exactly that when constructing givcipher and aead so
this patch adds support for that by setting the tested bit in
type but clearing it in mask. This combination is currently
unused.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
FIPS 140-2 specifies that all access to various cryptographic modules be
prevented in the event that any of the provided self tests fail on the various
implemented algorithms. We already panic when any of the test in testmgr.c
fail when we are operating in fips mode. The continuous test in the cprng here
was missed when that was implmented. This code simply checks for the
fips_enabled flag if the test fails, and warns us via syslog or panics the box
accordingly.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pseudo RNGs provide predictable outputs based on input parateters {key, V, DT},
the idea behind them is that only the user should know what the inputs are.
While its nice to have default known values for testing purposes, it seems
dangerous to allow the use of those default values without some sort of safety
measure in place, lest an attacker easily guess the output of the cprng. This
patch forces the NEED_RESET flag on when allocating a cprng context, so that any
user is forced to reseed it before use. The defaults can still be used for
testing, but this will prevent their inadvertent use, and be more secure.
Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Intel AES-NI is a new set of Single Instruction Multiple Data (SIMD)
instructions that are going to be introduced in the next generation of
Intel processor, as of 2009. These instructions enable fast and secure
data encryption and decryption, using the Advanced Encryption Standard
(AES), defined by FIPS Publication number 197. The architecture
introduces six instructions that offer full hardware support for
AES. Four of them support high performance data encryption and
decryption, and the other two instructions support the AES key
expansion procedure.
The white paper can be downloaded from:
http://softwarecommunity.intel.com/isn/downloads/intelavx/AES-Instructions-Set_WP.pdf
AES may be used in soft_irq context, but MMX/SSE context can not be
touched safely in soft_irq context. So in_interrupt() is checked, if
in IRQ or soft_irq context, the general x86_64 implementation are used
instead.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
cryptd_alloc_ablkcipher() will allocate a cryptd-ed ablkcipher for
specified algorithm name. The new allocated one is guaranteed to be
cryptd-ed ablkcipher, so the blkcipher underlying can be gotten via
cryptd_ablkcipher_child().
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We're currently checking the frontend type in init_tfm. This is
completely pointless because the fact that we're called at all
means that the frontend is ours so the type must match as well.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
It turns out that LRW has never worked properly on big endian.
This was never discussed because nobody actually used it that
way. In fact, it was only discovered when Geert Uytterhoeven
loaded it through tcrypt which failed the test on it.
The fix is straightforward, on big endian the to find the nth
bit we should be grouping them by words instead of bytes. So
setbit128_bbe should xor with 128 - BITS_PER_LONG instead of
128 - BITS_PER_BYTE == 0x78.
Tested-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
It's illegal to call flush_dcache_page on slab pages on a number
of architectures. So this patch avoids doing so if PageSlab is
true.
In future we can move the flush_dcache_page call to those page
cache users that actually need it.
Reported-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Geert Uytterhoeven pointed out that we're not zeroing all the
memory when freeing a transform. This patch fixes it by calling
ksize to ensure that we zero everything in sight.
Reported-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Module reference counting for shash is incorrect: when
a new shash transformation is created the refcount is not
increased as it should.
Signed-off-by: Adrian-Ken Rueegsegger <rueegsegger@swiss-it.ch>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When we complete a test we'll notify everyone waiting on it, drop
the mutex, and then remove the test larval (after reacquiring the
mutex). If one of the notified parties tries to register another
algorithm with the same driver name prior to the removal of the
test larval, they will fail with EEXIST as only one algorithm of
a given name can be tested at any time.
This broke the initialisation of aead and givcipher algorithms as
they will register two algorithms with the same driver name, in
sequence.
This patch fixes the problem by marking the larval as dead before
we drop the mutex, and also ignoring all dead or dying algorithms
on the registration path.
Tested-by: Andreas Steffen <andreas.steffen@strongswan.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Its a valid use case to have null associated data in a ccm vector, but
this case isn't being handled properly right now.
The following ccm decryption/verification test vector, using the
rfc4309 implementation regularly triggers a panic, as will any
other vector with null assoc data:
* key: ab2f8a74b71cd2b1ff802e487d82f8b9
* iv: c6fb7d800d13abd8a6b2d8
* Associated Data: [NULL]
* Tag Length: 8
* input: d5e8939fc7892e2b
The resulting panic looks like so:
Unable to handle kernel paging request at ffff810064ddaec0 RIP:
[<ffffffff8864c4d7>] :ccm:get_data_to_compute+0x1a6/0x1d6
PGD 8063 PUD 0
Oops: 0002 [1] SMP
last sysfs file: /module/libata/version
CPU 0
Modules linked in: crypto_tester_kmod(U) seqiv krng ansi_cprng chainiv rng ctr aes_generic aes_x86_64 ccm cryptomgr testmgr_cipher testmgr aead crypto_blkcipher crypto_a
lgapi des ipv6 xfrm_nalgo crypto_api autofs4 hidp l2cap bluetooth nfs lockd fscache nfs_acl sunrpc ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink xt_
tcpudp iptable_filter ip_tables x_tables dm_mirror dm_log dm_multipath scsi_dh dm_mod video hwmon backlight sbs i2c_ec button battery asus_acpi acpi_memhotplug ac lp sg
snd_intel8x0 snd_ac97_codec ac97_bus snd_seq_dummy snd_seq_oss joydev snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss ide_cd snd_pcm floppy parport_p
c shpchp e752x_edac snd_timer e1000 i2c_i801 edac_mc snd soundcore snd_page_alloc i2c_core cdrom parport serio_raw pcspkr ata_piix libata sd_mod scsi_mod ext3 jbd uhci_h
cd ohci_hcd ehci_hcd
Pid: 12844, comm: crypto-tester Tainted: G 2.6.18-128.el5.fips1 #1
RIP: 0010:[<ffffffff8864c4d7>] [<ffffffff8864c4d7>] :ccm:get_data_to_compute+0x1a6/0x1d6
RSP: 0018:ffff8100134434e8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8100104898b0 RCX: ffffffffab6aea10
RDX: 0000000000000010 RSI: ffff8100104898c0 RDI: ffff810064ddaec0
RBP: 0000000000000000 R08: ffff8100104898b0 R09: 0000000000000000
R10: ffff8100103bac84 R11: ffff8100104898b0 R12: ffff810010489858
R13: ffff8100104898b0 R14: ffff8100103bac00 R15: 0000000000000000
FS: 00002ab881adfd30(0000) GS:ffffffff803ac000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffff810064ddaec0 CR3: 0000000012a88000 CR4: 00000000000006e0
Process crypto-tester (pid: 12844, threadinfo ffff810013442000, task ffff81003d165860)
Stack: ffff8100103bac00 ffff8100104898e8 ffff8100134436f8 ffffffff00000000
0000000000000000 ffff8100104898b0 0000000000000000 ffff810010489858
0000000000000000 ffff8100103bac00 ffff8100134436f8 ffffffff8864c634
Call Trace:
[<ffffffff8864c634>] :ccm:crypto_ccm_auth+0x12d/0x140
[<ffffffff8864cf73>] :ccm:crypto_ccm_decrypt+0x161/0x23a
[<ffffffff88633643>] :crypto_tester_kmod:cavs_test_rfc4309_ccm+0x4a5/0x559
[...]
The above is from a RHEL5-based kernel, but upstream is susceptible too.
The fix is trivial: in crypto/ccm.c:crypto_ccm_auth(), pctx->ilen contains
whatever was in memory when pctx was allocated if assoclen is 0. The tested
fix is to simply add an else clause setting pctx->ilen to 0 for the
assoclen == 0 case, so that get_data_to_compute() doesn't try doing
things its not supposed to.
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When we get left-over bits from a slow walk, it means that the
underlying cipher has gone troppo. However, as we're handling
that case we should ensure that the caller terminates the walk.
This patch does this by setting walk->nbytes to zero.
Reported-by: Roel Kluin <roel.kluin@gmail.com>
Reported-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As it is if an algorithm with a zero-length IV is used (e.g.,
NULL encryption) with authenc, authenc may generate an SG entry
of length zero, which will trigger a BUG check in the hash layer.
This patch fixes it by skipping the IV SG generation if the IV
size is zero.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that clients no longer need to be notified of channel arrival
dma_async_client_register can simply increment the dmaengine_ref_count.
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
async_tx and net_dma each have open-coded versions of issue_pending_all,
so provide a common routine in dmaengine.
The implementation needs to walk the global device list, so implement
rcu to allow dma_issue_pending_all to run lockless. Clients protect
themselves from channel removal events by holding a dmaengine reference.
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Allowing multiple clients to each define their own channel allocation
scheme quickly leads to a pathological situation. For memory-to-memory
offload all clients can share a central allocator.
This simply moves the existing async_tx allocator to dmaengine with
minimal fixups:
* async_tx.c:get_chan_ref_by_cap --> dmaengine.c:nth_chan
* async_tx.c:async_tx_rebalance --> dmaengine.c:dma_channel_rebalance
* split out common code from async_tx.c:__async_tx_find_channel -->
dma_find_channel
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Simply, if a client wants any dmaengine channel then prevent all dmaengine
modules from being removed. Once the clients are done re-enable module
removal.
Why?, beyond reducing complication:
1/ Tracking reference counts per-transaction in an efficient manner, as
is currently done, requires a complicated scheme to avoid cache-line
bouncing effects.
2/ Per-transaction ref-counting gives the false impression that a
dma-driver can be gracefully removed ahead of its user (net, md, or
dma-slave)
3/ None of the in-tree dma-drivers talk to hot pluggable hardware, but
if such an engine were built one day we still would not need to notify
clients of remove events. The driver can simply return NULL to a
->prep() request, something that is much easier for a client to handle.
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
async_tx.ko is a consumer of dma channels. A circular dependency arises
if modules in drivers/dma rely on common code in async_tx.ko. It
prevents either module from being unloaded.
Move dma_wait_for_async_tx and async_tx_run_dependencies to dmaeninge.o
where they should have been from the beginning.
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
