The acpi_query_osc() function can be called for the ACPI object that
doesn't have _OSC method. In this case, acpi_get_osc_data() would
allocate a useless memory region. To avoid this, we need to check the
existence of _OSC before calling acpi_get_osc_data() in acpi_query_osc().
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Some versions of X used the mprotect workaround to change caching type from UC
to WB, so that it can then use mtrr to program WC for that region [1]. Change
the mmap of pci space through /sys or /proc interfaces from UC to UC_MINUS.
With this change, X will not need to use mprotect workaround to get WC type
since the MTRR mapping type will be honored.
The bug in mprotect that clobbers PAT bits is fixed in a follow on patch. So,
this X workaround will stop working as well.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This applies the NVidia MSI enabled flag for HT capable devices quirk
to ALi bridges as well.
As described in more detail in http://bugzilla.kernel.org/show_bug.cgi?id=10667
this is required for my board which is using an nForce 3 250Gb chipset with an
ALi M1695 northbridge.
It fixes a regression introduced in 2.6.24 that made the internal NIC of the
board unusable (MSI initialisation of the NIC but disabled MSI on the
northbridge devices.
Signed-off-by: Björn Krombholz <fox.box@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The following patch changes the intel-iommu.c code to use the TSC
instead of jiffies for detecting bad DMAR functionality. Some systems
with bad bios's have been seen to hang in early boot spinning in the
IOMMU_WAIT_IO macro. This patch will replace the infinite loop with a call to
panic.
Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The pci_osc_control_set() function can be called for the ACPI object
that doesn't have _OSC method. In this case, acpi_get_osc_data() would
allocate a useless memory region. To avoid this, we need to check the
existence of _OSC before calling acpi_get_osc_data(). Here is a patch
to fix this problem in pci_osc_control_set.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
There is an IA64 system here which have two pci root bridges with _OSC.
One _OSC disables SHPC control bit but the other not. Below patch makes
_OSC data per-device instead of one global, otherwise linux takes both
root bridges don't support SHPC.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Rene Herman reported:
> commit 8779f2fc3b
>
> "x86: don't try to allocate from DMA zone at first"
>
> breaks all of ISA DMA. Or all of ALSA ISA DMA at least. All
> ISA soundcards are silent following that commit -- no error
> messages, everything appears fine, just silence.
That patch is buggy. We had an implicit assumption that
dev = NULL for ISA devices that require 24bit DMA.
The recent work on x86 dma_alloc_coherent() breaks the ISA DMA buffer
allocation, which is represented by "dev = NULL" and requires 24bit
DMA implicitly.
Bisected-by: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Fix uninitialized variable in __pci_osc_support_set().
If the ACPI namespace doesn't have any device object corresponding to
the specified hid, 'retval' in __pci_osc_support_set() is not changed
by the acpi_query_osc() callback. Since 'retval' is not initizlized in
the current implementation, the contents of 'retval' is undefined in
this case. This causes a mis-handling of ctrlset_buf[OSC_SUPPORT_TYPE]
and will cause an unexpected result in the subsequent
pci_osc_control_set() call as a result.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Another addendum to commit c9e587abfd
("vt: fix background color on line feed").
fbcon still was not doing the right thing (read: continued to do old
behavior). fbcon_clear() seems to clear the new line (e.g. where your new
prompt appears after doing echo -en "\e[42mfoo\n"), while scr_memsetw clears
the previous one only (where "foo" appears). So just temporarily set the
video_erase_char to the scrl_erase_char so that fbcon_clear does the right
thing.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Addendum to commit c9e587abfd ("vt: fix
background color on line feed").
vc->vc_scrl_erase_char was not updated when fbcon switches between
256- and 512-glyph fonts.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The driver uses printk(), but does not include <linux/kernel.h> -- add it.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Bigga <ab@mycable.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Watchdog handlers within the driver make use of "save_client" -- make sure it
has been initalized before the handlers are registered.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Bigga <ab@mycable.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/char/synclink_gt.c: In function 'put_char':
drivers/char/synclink_gt.c:919: warning: 'ret' may be used uninitialized in this function
The compiler speaketh truth.
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
bdevname() fills the buffer that it is given as a parameter, so calling
strcpy() or snprintf() on the returned value is redundant (and probably not
guaranteed to work - I don't think strcpy and snprintf support overlapping
buffers.)
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prior to 2.6.26 fuse only supported single page write requests. In theory all
fuse filesystem should be able support bigger than 4k writes, as there's
nothing in the API to prevent it. Unfortunately there's a known case in
NTFS-3G where big writes cause filesystem corruption. There could also be
other filesystems, where the lack of testing with big write requests would
result in bugs.
To prevent such problems on a kernel upgrade, disable big writes by default,
but let filesystems set a flag to turn it on.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Szabolcs Szakacsits <szaka@ntfs-3g.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When mm destruction happens, we should pass mm_update_next_owner() the old mm.
But unfortunately new mm is passed in exec_mmap().
Thus, kernel panic is possible when a multi-threaded process uses exec().
Also, the owner member comment description is wrong. mm->owner does not
necessarily point to the thread group leader.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: "Paul Menage" <menage@google.com>
Cc: "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current driver may cause glitches on SPI CLK line since one must disable
the SPI controller before changing any HW settings. Fix this by implementing
a local spi_transfer function that won't change speed and/or word size while
CS is active.
While doing that heavy lifting a few other issues were addressed too:
- Make word size 16 and 32 work too.
- Honor bits_per_word and speed_hz in spi transaction.
- Optimize the common path.
This also stops using the "bitbang" framework (except for a few constants).
[Roel Kluin <12o3l@tiscali.nl>: "irq" needs to be signed]
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They aren't used. They were briefly used as part of some other patches to
provide an alternative format for displaying some /proc and /sys cpumasks.
They probably should have been removed when those other patches were dropped,
in favor of a different solution.
Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: "Mike Travis" <travis@sgi.com>
Cc: "Bert Wesarg" <bert.wesarg@googlemail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_FB_DEFERRED_IO can not be turned off, while it's already selected
automatically by the drivers that need it.
Although it's nice to have more compile-coverage, not being able to disable a
rarely used feature is annoying.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix divider calculation and allow CLKVAL = 0 (divisor 2)
It was not possible to get the clock value 0 (divisor 2) because
the test "<=0" force the BYPASS bit to be activated instead.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Per Hedblom <per.hedblom@abem.se>
Cc: Roel Kluin <12o3l@tiscali.nl>
Cc: Jan Weber <jw022609@uni-greifswald.de>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The input argument to rtc_time_to_tm() is unsigned as well as are members of
the output structure. However signed arithmetic is used within for
calculations leading to incorrect results for input values outside the signed
positive range. If this happens the time of day returned is out of range.
Found the problem when fiddling with the RTC and the driver where year was set
to an unexpectedly large value like 2070, e.g.:
rtc0: setting system clock to 2070-01-01 1193046:71582832:26 UTC (3155760954)
while it should be:
rtc0: setting system clock to 2070-01-01 00:15:54 UTC (3155760954)
Changing types to unsigned fixes the problem.
[akpm@linux-foundation.org: remove old-fashioned `register' keyword]
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Include the missing kcrctab and kcrctab_unused sections into the m68knommu
linker script.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is an ability to lose an initcall return value if it happened with irq
disabled or imbalanced preemption (and if we debug initcall).
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Update the Geode list location in the MAINTAINERS file.
Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix an oops with a corrupted hfs+ image.
See http://bugzilla.kernel.org/show_bug.cgi?id=10548 for details.
Problem is that we call hfs_btree_open() from hfsplus_fill_super() to set
HFSPLUS_SB(sb).[ext_tree|cat_tree] Both trees are still NULL at this moment.
If hfs_btree_open() fails for any reason it calls iput() on the page, which
gets to hfsplus_releasepage() which tries to access HFSPLUS_SB(sb).* which is
still NULL and oopses while dereferencing it.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PA-RISC to aid debugging prints out the zonelists setup by the system. A
bad call to node_zonelist() breaks at compile-time. This patch fixes it.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have to set the ISAPNP register index when setting an IRQ via the sysfs
interface. We already do it for IO, MEM, and DMA resources; I just missed the
IRQ one.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This would appear to be the last reference to TOPDIR in the entire tree, after
which i'm guessing that variable can be dropped.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The function framebuffer_release just calls kfree, so calling kfree
subsequently on the same argument represents a double free. The comments with
the definition of framebuffer_release in drivers/video/fbsysfs.c suggest that
a more elaborate definition of this function is planned, such that the
splitting up of framebuffer_release and kfree as done in the second instance
might someday make sense, but it does not make sense now.
This was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
expression E;
@@
* kfree(E);
...
* framebuffer_release(E);
@@
expression E;
@@
* framebuffer_release(E);
...
* kfree(E);
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Grigory Tolstolytkin <gtolstolytkin@ru.mvista.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a sentence about when fan speed increases to maximum.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is currently no way to query the bounding set of another task. As there
appears to be no security reason not to, and as Michael Kerrisk points out the
following valid reasons to do so exist:
* consistency (I can see all of the other per-thread/process sets in
/proc/.../status)
* debugging -- I could imagine that it would make the job of debugging an
application that uses capabilities a little simpler.
this patch adds the bounding set to /proc/self/status right after the
effective set.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit bd2ab67030 "md: close a livelock window
in handle_parity_checks5" introduced a bug in handling 'repair' operations.
After a repair operation completes we clear the state bits tracking this
operation. However, they are cleared too early and this results in the code
deciding to re-run the parity check operation. Since we have done the repair
in memory the second check does not find a mismatch and thus does not do a
writeback.
Test results:
$ echo repair > /sys/block/md0/md/sync_action
$ cat /sys/block/md0/md/mismatch_cnt
51072
$ echo repair > /sys/block/md0/md/sync_action
$ cat /sys/block/md0/md/mismatch_cnt
0
(also fix incorrect indentation)
Cc: <stable@kernel.org>
Tested-by: George Spelvin <linux@horizon.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Improve clock calculation precision (to kHz from MHz) and removes parameter
field vclk from the tridentfb_par structure.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove redundant enable_mmio() call as the mmio mode is enabled in the probe
function earlier.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Otherwise it can only take the values 0/-1 which doesn't seem to
have been intended.
drivers/mmc/host/sdhci.h:190:20: error: dubious one-bit signed bitfield
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Pierre Ossman <drzeus-list@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sometimes, vfs_quota_off() is called on a partially set up super block (for
example when fill_super() fails for some reason). In such cases we cannot
call ->sync_fs() because it can Oops because of not properly filled in super
block. So in case we find there's not quota to turn off, we just skip
everything and return which fixes the above problem.
[akpm@linux-foundation.org: fxi tpyo]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When accessing cpu_online_map, we should prevent dynamic changing
of cpu_online_map by get_online_cpus().
Unfortunately, all_vm_events() doesn't do that.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As the subject says this patch adds the support for kernel preemption on
m68knommu Coldfire. I thing the same changes could be applied to 68360 &
68328 but since I don't have the HW, I don't touch it. Kconfig enables the
preemption item only on coldfire.
This is a missing chunk from Sebastian's original patch that I lost from the
first submission.
Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dget(dentry->d_parent) --> dget_parent(dentry)
unlock_parent() is racy and unnecessary. Replace single caller with
unlock_dir().
There are several other suspect uses of ->d_parent in ecryptfs...
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In preparation for supporting greater than 64 partitions replace partid_t by
short in drivers/misc/sgi-xp.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Acked-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make XP return values more generic to XP and not so tied to XPC by changing
enum xpc_retval to xp_retval, along with changing return value prefixes from
xpc to xp. Also, cleanup a comment block that referenced some of these return
values as well as the handling of BTE related return values.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Acked-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a typo in pxa2xx_spi.c, comment says "Enable the SSP clock", code
says: clk_disable ... so after resume, the SSP is dead.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Ned Forrester <nforrester@whoi.edu>
Cc: Stephen Street <stephen@streetfiresound.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alarm delivery could be noticably late in the !CONFIG_NOHZ case because lost
ticks weren't being taken into account. This is now treated more carefully,
with the time between ticks being calculated and the appropriate number of
ticks delivered to the timekeeping system.
Cc: Nix <nix@esperi.org.uk>
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>
Give random.c a style workover while I'm changing it.
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>
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>
