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path: root/drivers/char/hw_random/core.c
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* hwrng: core - sleep interruptible in readJiri Slaby2015-12-041-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hwrng kthread can be waiting via hwrng_fillfn for some data from a rng like virtio-rng: hwrng D ffff880093e17798 0 382 2 0x00000000 ... Call Trace: [<ffffffff817339c6>] wait_for_completion_killable+0x96/0x210 [<ffffffffa00aa1b7>] virtio_read+0x57/0xf0 [virtio_rng] [<ffffffff814f4a35>] hwrng_fillfn+0x75/0x130 [<ffffffff810aa243>] kthread+0xf3/0x110 And when some user program tries to read the /dev node in this state, we get: rngd D ffff880093e17798 0 762 1 0x00000004 ... Call Trace: [<ffffffff817351ac>] mutex_lock_nested+0x15c/0x3e0 [<ffffffff814f478e>] rng_dev_read+0x6e/0x240 [<ffffffff81231958>] __vfs_read+0x28/0xe0 [<ffffffff81232393>] vfs_read+0x83/0x130 And this is indeed unkillable. So use mutex_lock_interruptible instead of mutex_lock in rng_dev_read and exit immediatelly when interrupted. And possibly return already read data, if any (as POSIX allows). v2: use ERESTARTSYS instead of EINTR Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: <linux-crypto@vger.kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Simplify RNG switching from sysfsLee Jones2015-09-211-1/+1
| | | | | | | | | | | | | | If we attempt to use sysfs to change the current RNG in the usual way i.e. issuing something like: `echo 8a8a000.rng > /sys/devices/virtual/misc/hw_random/rng_current` ... it will fail because the code doesn't currently take the '\n' into consideration. Well, now it does. Signed-off-by: Lee Jones <lee.jones@linaro.org> Acked-by: Peter Korsgaard <peter@korsgaard.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - correct error check of kthread_run callMartin Schwidefsky2015-07-281-1/+1
| | | | | | | | | | | The kthread_run() function can return two different error values but the hwrng core only checks for -ENOMEM. If the other error value -EINTR is returned it is assigned to hwrng_fill and later used on a kthread_stop() call which naturally crashes. Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Merge tag 'char-misc-4.1-rc1' of ↵Linus Torvalds2015-04-211-23/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver updates from Greg KH: "Here's the big char/misc driver patchset for 4.1-rc1. Lots of different driver subsystem updates here, nothing major, full details are in the shortlog. All of this has been in linux-next for a while" * tag 'char-misc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (133 commits) mei: trace: remove unused TRACE_SYSTEM_STRING DTS: ARM: OMAP3-N900: Add lis3lv02d support Documentation: DT: lis302: update wakeup binding lis3lv02d: DT: add wakeup unit 2 and wakeup threshold lis3lv02d: DT: use s32 to support negative values Drivers: hv: hv_balloon: correctly handle num_pages>INT_MAX case Drivers: hv: hv_balloon: correctly handle val.freeram<num_pages case mei: replace check for connection instead of transitioning mei: use mei_cl_is_connected consistently mei: fix mei_poll operation hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg() Drivers: hv: hv_balloon: survive ballooning request with num_pages=0 Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor function Drivers: hv: hv_balloon: do not online pages in offline blocks hv: remove the per-channel workqueue hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind() hv: run non-blocking message handlers in the dispatch tasklet coresight: moving to new "hwtracing" directory coresight-tmc: Adding a status interface to sysfs coresight: remove the unnecessary configuration coresight-default-sink ...
| * hwrng: Avoid manual device_create_file() callsTakashi Iwai2015-03-251-23/+11
| | | | | | | | | | | | | | | | | | | | Use the new group field of struct miscdevice for managing the sysfs entries instead of manually adding/removing via device_create_file() and device_remove_file(). This simplifies the code a lot and fixes the possible races. Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | hwrng: core - allow perfect entropy from hardware devicesKeith Packard2015-03-181-1/+2
| | | | | | | | | | | | | | | | | | Hardware random number quality is measured from 0 (no entropy) to 1024 (perfect entropy). Allow hardware devices to assert the full range by truncating the device-provided value at 1024 instead of 1023. Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* | hwrng: add devm_* interfacesDmitry Torokhov2015-03-161-0/+42
|/ | | | | | | | | This change adds devm_hwrng_register and devm_hwrng_unregister which use can simplify error unwinding and unbinding code paths in device drivers. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Move hwrng_init call into set_current_rngHerbert Xu2014-12-261-14/+16
| | | | | | | | We always do hwrng_init in set_current_rng. In fact, our current reference count system relies on this. So make this explicit by moving hwrng_init into set_current_rng. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Drop current rng in set_current_rngHerbert Xu2014-12-261-1/+2
| | | | | | | Rather than having callers of set_current_rng call drop_current_rng, we can do it directly in set_current_rng. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Do not register device opportunisticallyHerbert Xu2014-12-261-11/+12
| | | | | | | | | | | | | Currently we only register the device when a valid RNG is added. However the way it's done is buggy because we test whether there is a current RNG to determine whether we need to register. As the current RNG may be missing due to a reinitialisation error this can lead to a reregistration of the device. As the device already has to handle a NULL current RNG anyway, let's just register the device always and remove the complexity. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Fix current_rng init/cleanup race yet againHerbert Xu2014-12-261-3/+11
| | | | | | | | | | The kref solution is still buggy because we were only focusing on the register/unregister race. The same race affects the setting of current_rng through sysfs. This patch fixes it by using kref_get_unless_zero. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Use struct completion for cleanup_doneHerbert Xu2014-12-261-9/+3
| | | | | | | There is no point in doing a manual completion for cleanup_done when struct completion fits in perfectly. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: don't init list element we're about to add to list.Rusty Russell2014-12-221-1/+0
| | | | | | | Another interesting anti-pattern. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: don't double-check old_rng.Rusty Russell2014-12-221-3/+2
| | | | | | | Interesting anti-pattern. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: fix unregister race.Rusty Russell2014-12-221-0/+12
| | | | | | | | | | The previous patch added one potential problem: we can still be reading from a hwrng when it's unregistered. Add a wait for zero in the hwrng_unregister path. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: use reference counts on each struct hwrng.Rusty Russell2014-12-221-43/+92
| | | | | | | | | | | | | | | | | | | | current_rng holds one reference, and we bump it every time we want to do a read from it. This means we only hold the rng_mutex to grab or drop a reference, so accessing /sys/devices/virtual/misc/hw_random/rng_current doesn't block on read of /dev/hwrng. Using a kref is overkill (we're always under the rng_mutex), but a standard pattern. This also solves the problem that the hwrng_fillfn thread was accessing current_rng without a lock, which could change (eg. to NULL) underneath it. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: move some code out mutex_lock for avoiding underlying deadlockAmos Kong2014-12-221-3/+3
| | | | | | | | | | | In next patch, we use reference counting for each struct hwrng, changing reference count also needs to take mutex_lock. Before releasing the lock, if we try to stop a kthread that waits to take the lock to reduce the referencing count, deadlock will occur. Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: place mutex around read functions and buffers.Rusty Russell2014-12-221-3/+17
| | | | | | | | | | | | | | There's currently a big lock around everything, and it means that we can't query sysfs (eg /sys/devices/virtual/misc/hw_random/rng_current) while the rng is reading. This is a real problem when the rng is slow, or blocked (eg. virtio_rng with qemu's default /dev/random backend) This doesn't help (it leaves the current lock untouched), just adds a lock to protect the read function and the static buffers, in preparation for transition. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* hwrng: core - Changed from using strncat to strlcatRickard Strandqvist2014-10-241-8/+4
| | | | | | | | | | | The buf is used to hold the list of hwrng devices registered. The old code ensures we don't walk off the end of buf as we fill it, but it's unnecessarily complicated and thus difficult to maintain. Simplify it by using strlcat. Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2014-08-101-6/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio updates from Rusty Russell. * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: Revert "hwrng: virtio - ensure reads happen after successful probe" virtio: rng: delay hwrng_register() till driver is ready virtio: rng: re-arrange struct elements for better packing virtio: rng: remove unused struct element virtio: Replace DEFINE_PCI_DEVICE_TABLE macro use virtio: console: remove unnecessary null test before debugfs_remove_recursive
| * Revert "hwrng: virtio - ensure reads happen after successful probe"Amit Shah2014-07-271-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit e052dbf554610e2104c5a7518c4d8374bed701bb. Now that we use the virtio ->scan() function to register with the hwrng core, we will not get read requests till probe is successfully finished. So revert the workaround we had in place to refuse read requests while we were not yet setup completely. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | Merge tag 'random_for_linus' of ↵Linus Torvalds2014-08-061-2/+65
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random Pull randomness updates from Ted Ts'o: "Cleanups and bug fixes to /dev/random, add a new getrandom(2) system call, which is a superset of OpenBSD's getentropy(2) call, for use with userspace crypto libraries such as LibreSSL. Also add the ability to have a kernel thread to pull entropy from hardware rng devices into /dev/random" * tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytes random: limit the contribution of the hw rng to at most half random: introduce getrandom(2) system call hw_random: fix sparse warning (NULL vs 0 for pointer) random: use registers from interrupted code for CPU's w/o a cycle counter hwrng: add per-device entropy derating hwrng: create filler thread random: add_hwgenerator_randomness() for feeding entropy from devices random: use an improved fast_mix() function random: clean up interrupt entropy accounting for archs w/o cycle counters random: only update the last_pulled time if we actually transferred entropy random: remove unneeded hash of a portion of the entropy pool random: always update the entropy pool under the spinlock
| * hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytesStephen Boyd2014-08-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | rng_get_data() returns the number of bytes read from the hardware. The entropy argument to add_hwgenerator_randomness() is passed directly to credit_entropy_bits() so we should be passing the number of bits, not bytes here. Fixes: be4000bc464 "hwrng: create filler thread" Acked-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * hw_random: fix sparse warning (NULL vs 0 for pointer)Torsten Duwe2014-07-151-1/+1
| | | | | | | | | | Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * hwrng: add per-device entropy deratingTorsten Duwe2014-07-151-1/+10
| | | | | | | | | | | | | | | | | | | | This patch introduces a derating factor to struct hwrng for the random bits going into the kernel input pool, and a common default derating for drivers which do not specify one. Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: H. Peter Anvin <hpa@zytor.com>
| * hwrng: create filler threadTorsten Duwe2014-07-151-5/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This can be viewed as the in-kernel equivalent of hwrngd; like FUSE it is a good thing to have a mechanism in user land, but for some reasons (simplicity, secrecy, integrity, speed) it may be better to have it in kernel space. This patch creates a thread once a hwrng registers, and uses the previously established add_hwgenerator_randomness() to feed its data to the input pool as long as needed. A derating factor is used to bias the entropy estimation and to disable this mechanism entirely when set to zero. Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: H. Peter Anvin <hpa@zytor.com>
* | hwrng: virtio - ensure reads happen after successful probeAmit Shah2014-07-141-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The hwrng core asks for random data in the hwrng_register() call itself from commit d9e7972619. This doesn't play well with virtio -- the DRIVER_OK bit is only set by virtio core on a successful probe, and we're not yet out of our probe routine when this call is made. This causes the host to not acknowledge any requests we put in the virtqueue, and the insmod or kernel boot process just waits for data to arrive from the host, which never happens. CC: Kees Cook <keescook@chromium.org> CC: Jason Cooper <jason@lakedaemon.net> CC: Herbert Xu <herbert@gondor.apana.org.au> CC: <stable@vger.kernel.org> # For v3.15+ Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* | hwrng: fetch randomness only after device initAmit Shah2014-07-141-8/+33
|/ | | | | | | | | | | | | | | | | | | Commit d9e7972619334 "hwrng: add randomness to system from rng sources" added a call to rng_get_data() from the hwrng_register() function. However, some rng devices need initialization before data can be read from them. This commit makes the call to rng_get_data() depend on no init fn pointer being registered by the device. If an init function is registered, this call is made after device init. CC: Kees Cook <keescook@chromium.org> CC: Jason Cooper <jason@lakedaemon.net> CC: Herbert Xu <herbert@gondor.apana.org.au> CC: <stable@vger.kernel.org> # For v3.15+ Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds2014-04-031-7/+10
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull crypto updates from Herbert Xu: "Here is the crypto update for 3.15: - Added 3DES driver for OMAP4/AM43xx - Added AVX2 acceleration for SHA - Added hash-only AEAD algorithms in caam - Removed tegra driver as it is not functioning and the hardware is too slow - Allow blkcipher walks over AEAD (needed for ARM) - Fixed unprotected FPU/SSE access in ghash-clmulni-intel - Fixed highmem crash in omap-sham - Add (zero entropy) randomness when initialising hardware RNGs - Fixed unaligned ahash comletion functions - Added soft module depedency for crc32c for initrds that use crc32c" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (60 commits) crypto: ghash-clmulni-intel - use C implementation for setkey() crypto: x86/sha1 - reduce size of the AVX2 asm implementation crypto: x86/sha1 - fix stack alignment of AVX2 variant crypto: x86/sha1 - re-enable the AVX variant crypto: sha - SHA1 transform x86_64 AVX2 crypto: crypto_wq - Fix late crypto work queue initialization crypto: caam - add missing key_dma unmap crypto: caam - add support for aead null encryption crypto: testmgr - add aead null encryption test vectors crypto: export NULL algorithms defines crypto: caam - remove error propagation handling crypto: hash - Simplify the ahash_finup implementation crypto: hash - Pull out the functions to save/restore request crypto: hash - Fix the pointer voodoo in unaligned ahash crypto: caam - Fix first parameter to caam_init_rng crypto: omap-sham - Map SG pages if they are HIGHMEM before accessing crypto: caam - Dynamic memory allocation for caam_rng_ctx object crypto: allow blkcipher walks over AEAD data crypto: remove direct blkcipher_walk dependency on transform hwrng: add randomness to system from rng sources ...
| * hwrng: add randomness to system from rng sourcesKees Cook2014-03-101-0/+7
| | | | | | | | | | | | | | | | | | | | | | When bringing a new RNG source online, it seems like it would make sense to use some of its bytes to make the system entropy pool more random, as done with all sorts of other devices that contain per-device or per-boot differences. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| * hwrng: cleanup in hwrng_register()Dan Carpenter2014-02-091-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My static checker complains that: drivers/char/hw_random/core.c:341 hwrng_register() warn: we tested 'old_rng' before and it was 'false' The problem is that sometimes we test "if (!old_rng)" and sometimes we test "if (must_register_misc)". The static checker knows they are equivalent but a human being reading the code could easily be confused. I have simplified the code by removing the "must_register_misc" variable and I have removed the redundant check on "if (!old_rng)". Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* | drivers/char: delete non-required instances of include <linux/init.h>Paul Gortmaker2014-02-071-1/+0
|/ | | | | | | | | | | | | | | | | | | | | None of these files are actually using any __init type directives and hence don't need to include <linux/init.h>. Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. Cc: David Airlie <airlied@linux.ie> Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Corey Minyard <minyard@acm.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Peter Huewe <peterhuewe@gmx.de> Cc: Ashley Lai <ashley@ashleylai.com> Cc: Marcel Selhorst <tpmdd@selhorst.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* hw_random: free rng_buffer at module exitSatoru Takeuchi2013-03-201-0/+9
| | | | | | | | | rng-core module allocates rng_buffer by kmalloc() since commit f7f154f1246ccc5a0a7e9ce50932627d60a0c878. But this buffer won't be freed and there is a memory leak possibility at module exit. Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* hw_random: make buffer usable in scatterlist.Rusty Russell2013-03-051-3/+16
| | | | | | | | | | | | | | | virtio_rng feeds the randomness buffer handed by the core directly into the scatterlist, since commit bb347d98079a547e80bd4722dee1de61e4dca0e8. However, if CONFIG_HW_RANDOM=m, the static buffer isn't a linear address (at least on most archs). We could fix this in virtio_rng, but it's actually far easier to just do it in the core as virtio_rng would have to allocate a buffer every time (it doesn't know how much the core will want to read). Reported-by: Aurelien Jarno <aurelien@aurel32.net> Tested-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org
* Update my e-mail addressMichael Büsch2011-07-071-1/+1
| | | | | Signed-off-by: Michael Buesch <m@bues.ch> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* BKL: remove extraneous #include <smp_lock.h>Arnd Bergmann2010-11-171-1/+0
| | | | | | | | | | The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* llseek: automatically add .llseek fopArnd Bergmann2010-10-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
* hwrng: core - Fix double unlock in rng_dev_readHerbert Xu2009-12-231-2/+3
| | | | | | | | When the loop terminates with size == 0 in rng_dev_read we will unlock the rng mutex twice. Reported-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Merge branch 'bkl-drivers-for-linus' of ↵Linus Torvalds2009-12-091-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'bkl-drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: agp: Remove the BKL from agp_open inifiband: Remove BKL from ipath_open() mips: Remove BKL from tb0219 drivers: Remove BKL from scx200_gpio drivers: Remove BKL from pc8736x_gpio parisc: Remove BKL from eisa_eeprom rtc: Remove BKL from efirtc input: Remove BKL from hp_sdc_rtc hw_random: Remove BKL from core macintosh: Remove BKL from ans-lcd nvram: Drop the bkl from non-generic nvram_llseek() nvram: Drop the bkl from nvram_llseek() mem_class: Drop the bkl from memory_open() spi: Remove BKL from spidev_open drivers: Remove BKL from cs5535_gpio drivers: Remove BKL from misc_open
| * hw_random: Remove BKL from coreThomas Gleixner2009-10-141-1/+0
| | | | | | | | | | | | | | | | | | hw_random core is completely serialized with rng_mutex. No need for the cycle_kernel_lock() magic. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20091010153349.844488872@linutronix.de> Cc: Herbert Xu <herbert@gondor.apana.org.au>
* | hwrng: core - Prevent too-small buffer sizesIan Molton2009-12-031-1/+2
| | | | | | | | | | | | | | | | This patch prevents the hw_random core using too small of a buffer on machines with small cacheline sizes. Signed-off-by: Ian Molton <ian.molton@collabora.co.uk> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6Herbert Xu2009-12-011-1/+1
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| * Driver-Core: extend devnode callbacks to provide permissionsKay Sievers2009-09-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This allows subsytems to provide devtmpfs with non-default permissions for the device node. Instead of the default mode of 0600, null, zero, random, urandom, full, tty, ptmx now have a mode of 0666, which allows non-privileged processes to access standard device nodes in case no other userspace process applies the expected permissions. This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | hwrng: core - Replace u32 in driver API with byte arrayIan Molton2009-12-011-43/+64
|/ | | | | | | | | | | | | This patch implements a new method by which hw_random hardware drivers can pass data to the core more efficiently, using a shared buffer. The old methods have been retained as a compatability layer until all the drivers have been updated. Signed-off-by: Ian Molton <ian.molton@collabora.co.uk> Acked-by: Matt Mackall <mpm@selenic.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Driver Core: misc: add nodename support for misc devices.Kay Sievers2009-06-151-0/+1
| | | | | | | | | | | This adds support for misc devices to report their requested nodename to userspace. It also updates a number of misc drivers to provide the needed subdirectory and device name to be used for them. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* hw-random: BKL pushdownArnd Bergmann2008-06-201-0/+2
| | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* PM: Remove destroy_suspended_device()Rafael J. Wysocki2008-04-191-5/+5
| | | | | | | | | | | | | | | | | | After 2.6.24 there was a plan to make the PM core acquire all device semaphores during a suspend/hibernation to protect itself from concurrent operations involving device objects. That proved to be too heavy-handed and we found a better way to achieve the goal, but before it happened, we had introduced the functions device_pm_schedule_removal() and destroy_suspended_device() to allow drivers to "safely" destroy a suspended device and we had adapted some drivers to use them. Now that these functions are no longer necessary, it seems reasonable to remove them and modify their users to use the normal device unregistration instead. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [S390] hw_random: allow rng_dev_read() to return hardware errors.Ralph Wuerthner2008-04-171-0/+4
| | | | | | | | | | | | | | | | The api for hardware random number generators is currently limited to devices that never fail. If the hardware is registered as a source for random numbers it has to work. This prevents the use of i/o based random number devices where the i/o might fail. Add a check for errors after the read from a hardware random number device. This patch is required to support large random numbers retrieved from the CEX2C cards on System z. Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* HWRNG: add possibility to remove hwrng devices during suspend/resumeRafael J. Wysocki2008-02-051-5/+5
| | | | | | | | | | | | | | | | | | Make it possible to unregister a Hardware Random Number Generator device object in a safe way during a suspend/resume cycle. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Michael Buesch <mb@bu3sch.de> Cc: Michael Buesch <mb@bu3sch.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Len Brown <lenb@kernel.org> Cc: Greg KH <greg@kroah.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [HWRNG]: move status polling loop to data_present callbacksPatrick McHardy2008-01-111-18/+6
| | | | | | | | | Handle waiting for new random within the drivers themselves, this allows to use better suited timeouts for the individual rngs. Signed-off-by: Patrick McHardy <kaber@trash.net> Acked-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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