linux/include
Jeff Dike 5d33e4d7fd uml: random driver fixes
The random driver would essentially hang if the host's /dev/random returned
-EAGAIN.  There was a test of need_resched followed by a schedule inside the
loop, but that didn't help and it's the wrong way to work anyway.

The right way is to ask for an interrupt when there is input available from
the host and handle it then rather than polling.

Now, when the host's /dev/random returns -EAGAIN, the driver asks for a wakeup
when there's randomness available again and sleeps.  The interrupt routine
just wakes up whatever processes are sleeping on host_read_wait.

There is an atomic_t, host_sleep_count, which counts the number of processes
waiting for randomness.  When this reaches zero, the interrupt is disabled.

An added complication is that async I/O notification was only recently added
to /dev/random (by me), so essentially all hosts will lack it.  So, we use the
sigio workaround here, which is to have a separate thread poll on the
descriptor and send an interrupt when there is input on it.  This mechanism is
activated when a process gets -EAGAIN (activating this multiple times is
harmless, if a bit wasteful) and deactivated by the last process still
waiting.

The module name was changed from "random" to "hw_random" in order for udev to
recognize it.

The sigio workaround needed some changes.  sigio_broken was added for cases
when we know that async notification doesn't work.  This is now called from
maybe_sigio_broken, which deals with pts devices.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-13 08:02:22 -07:00
..
acpi ACPICA: update Intel copyright 2008-04-23 23:00:13 -04:00
asm-alpha fix asm-alpha/types.h breakage 2008-05-04 14:45:55 -07:00
asm-arm [ARM] pxa: Fix RCSR handling 2008-05-08 18:04:02 +01:00
asm-avr32 avr32: types: use <asm-generic/int-*.h> for the avr32 architecture 2008-05-02 16:18:20 -07:00
asm-blackfin Blackfin Serial Driver: abstract away DLAB differences into header 2008-05-07 11:41:26 +08:00
asm-cris cris: types: use <asm-generic/int-*.h> for the cris architecture 2008-05-02 16:18:20 -07:00
asm-frv frv: types: use <asm-generic/int-*.h> for the frv architecture 2008-05-02 16:18:20 -07:00
asm-generic types: add C99-style constructors to <asm-generic/int-*.h> 2008-05-02 16:18:42 -07:00
asm-h8300 h8300: types: use <asm-generic/int-*.h> for the h8300 architecture 2008-05-02 16:18:21 -07:00
asm-ia64 ia64: types: use <asm-generic/int-*.h> for the ia64 architecture 2008-05-02 16:18:21 -07:00
asm-m32r m32r: types: use <asm-generic/int-*.h> for the m32r architecture 2008-05-02 16:18:21 -07:00
asm-m68k m68k: remove old mac_esp cruft 2008-05-05 12:38:50 -07:00
asm-m68knommu m68knommu: rework definition of HZ 2008-05-01 08:08:36 -07:00
asm-mips [MIPS] Get rid of __ilog2 2008-05-12 16:46:55 +01:00
asm-mn10300 MN10300: Make cpu_relax() invoke barrier() 2008-05-08 10:49:39 -07:00
asm-parisc parisc: types: use <asm-generic/int-*.h> for the parisc architecture 2008-05-02 16:18:32 -07:00
asm-powerpc Merge branch 'for-2.6.26' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer/powerpc-4xx into merge 2008-05-09 20:12:06 +10:00
asm-ppc [POWERPC] ppc: More compile fixes 2008-05-12 22:57:51 +10:00
asm-s390 types: s390: fix #ifdef reversal in <asm-s390/types.h> 2008-05-12 08:49:59 -07:00
asm-sh sh: Fix DMAC base address for SH7709S 2008-05-09 19:04:12 +09:00
asm-sparc sparc32: Fix build. 2008-05-11 15:47:05 -07:00
asm-sparc64 sparc: Fix debugger syscall restart interactions. 2008-05-11 02:07:19 -07:00
asm-um uml: random driver fixes 2008-05-13 08:02:22 -07:00
asm-v850 v850: types: use <asm-generic/int-*.h> for the v850 architecture 2008-05-02 16:18:41 -07:00
asm-x86 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86 2008-05-10 21:10:48 -07:00
asm-xtensa xtensa: types: use <asm-generic/int-*.h> for the xtensa architecture 2008-05-02 16:18:42 -07:00
crypto [CRYPTO] api: Fix scatterwalk_sg_chain 2008-05-01 18:22:28 +08:00
keys KEYS: Fix the comment to match the file name in rxrpc-type.h. 2008-04-21 22:43:55 +00:00
linux Make 'cond_resched()' nullification depend on PREEMPT_BKL 2008-05-12 13:34:13 -07:00
math-emu
media i2c: Convert some more new-style drivers to use module aliasing 2008-05-11 20:37:06 +02:00
mtd
net ip: Make use of the inline function dst_metric_locked() 2008-05-04 22:12:43 -07:00
pcmcia
rdma IB: expand ib_umem_get() prototype 2008-04-29 08:06:12 -07:00
rxrpc
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2008-05-02 13:52:35 -07:00
sound [ALSA] Add MPU401_INFO_NO_ACK bitflag 2008-04-29 19:01:56 +02:00
video fbdev: platforming hecubafb and n411 2008-04-28 08:58:41 -07:00
xen xen: add balloon driver 2008-04-24 23:57:33 +02:00
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