Commit Graph

11 Commits

Author SHA1 Message Date
Matthew Wilcox b76ba4af4d drivers/hwspinlock: use correct radix tree API
radix_tree_is_indirect_ptr() is an internal API.  The correct call to
use is radix_tree_deref_retry() which has the appropriate unlikely()
annotation.

Fixes: c6400ba7e1 ("drivers/hwspinlock: fix race between radix tree insertion and lookup")
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00
Matthew Wilcox c6400ba7e1 drivers/hwspinlock: fix race between radix tree insertion and lookup
of_hwspin_lock_get_id() is protected by the RCU lock, which means that
insertions can occur simultaneously with the lookup.  If the radix tree
transitions from a height of 0, we can see a slot with the indirect_ptr
bit set, which will cause us to at least read random memory, and could
cause other havoc.

Fix this by using the newly introduced radix_tree_iter_retry().

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-03 08:28:43 -08:00
Suman Anna fb7737e949 hwspinlock/core: add device tree support
This patch adds a new OF-friendly API of_hwspin_lock_get_id()
for hwspinlock clients to use/request locks from a hwspinlock
device instantiated through a device-tree blob. This new API
can be used by hwspinlock clients to get the id for a specific
lock using the phandle + args specifier, so that it can be
requested using the available hwspin_lock_request_specific()
API.

Signed-off-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
[small comment clarification]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2015-05-02 09:54:30 +03:00
Li Fei c10b90d85a hwspinlock: fix __hwspin_lock_request error path
Even in failed case of pm_runtime_get_sync, the usage_count
is incremented. In order to keep the usage_count with correct
value and runtime power management to behave correctly, call
pm_runtime_put_noidle in such case.

In __hwspin_lock_request, module_put is also called before
return in pm_runtime_get_sync failed case.

Cc: stable@vger.kernel.org
Signed-off-by Liu Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Li Fei <fei.li@intel.com>
[edit commit log]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2013-04-05 17:45:11 +03:00
Wei Yongjun e352614cd3 hwspinlock/core: move the dereference below the NULL test
The dereference should be moved below the NULL test.

spatch with a semantic match is used to found this.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2012-09-10 13:19:25 +03:00
Shinya Kuribayashi 476a7eeb60 hwspinlock/core: use global ID to register hwspinlocks on multiple devices
Commit 300bab9770 (hwspinlock/core: register a bank of hwspinlocks in a
single API call, 2011-09-06) introduced 'hwspin_lock_register_single()'
to register numerous (a bank of) hwspinlock instances in a single API,
'hwspin_lock_register()'.

At which time, 'hwspin_lock_register()' accidentally passes 'local IDs'
to 'hwspin_lock_register_single()', despite that ..._single() requires
'global IDs' to register hwspinlocks.

We have to convert into global IDs by supplying the missing 'base_id'.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
[ohad: fix error path of hwspin_lock_register, too]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2012-07-07 22:35:30 +03:00
Ohad Ben-Cohen 300bab9770 hwspinlock/core: register a bank of hwspinlocks in a single API call
Hardware Spinlock devices usually contain numerous locks (known
devices today support between 32 to 256 locks).

Originally hwspinlock core required drivers to register (and later,
when needed, unregister) each lock separately.

That worked, but required hwspinlocks drivers to do a bit extra work
when they were probed/removed.

This patch changes hwspin_lock_{un}register() to allow a bank of
hwspinlocks to be {un}registered in a single invocation.

A new 'struct hwspinlock_device', which contains an array of 'struct
hwspinlock's is now being passed to the core upon registration (so
instead of wrapping each struct hwspinlock, a priv member has been added
to allow drivers to piggyback their private data with each hwspinlock).

While at it, several per-lock members were moved to be per-device:
1. struct device *dev
2. struct hwspinlock_ops *ops

In addition, now that the array of locks is handled by the core,
there's no reason to maintain a per-lock 'int id' member: the id of the
lock anyway equals to its index in the bank's array plus the bank's
base_id.
Remove this per-lock id member too, and instead use a simple pointers
arithmetic to derive it.

As a result of this change, hwspinlocks drivers are now simpler and smaller
(about %20 code reduction) and the memory footprint of the hwspinlock
framework is reduced.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2011-09-21 19:45:34 +03:00
Juan Gutierrez 93b465c2e1 hwspinlock/core: use a mutex to protect the radix tree
Since we're using non-atomic radix tree allocations, we
should be protecting the tree using a mutex and not a
spinlock.

Non-atomic allocations and process context locking is good enough,
as the tree is manipulated only when locks are registered/
unregistered/requested/freed.

The locks themselves are still protected by spinlocks of course,
and mutexes are not involved in the locking/unlocking paths.

Cc: <stable@kernel.org>
Signed-off-by: Juan Gutierrez <jgutierrez@ti.com>
[ohad@wizery.com: rewrite the commit log, #include mutex.h, add minor
commentary]
[ohad@wizery.com: update register/unregister parts in hwspinlock.txt]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2011-09-21 19:45:32 +03:00
Ohad Ben-Cohen c3c1250e93 hwspinlock/core/omap: fix id issues on multiple hwspinlock devices
hwspinlock devices provide system-wide hardware locks that are used
by remote processors that have no other way to achieve synchronization.

To achieve that, each physical lock must have a system-wide id number
that is agreed upon, otherwise remote processors can't possibly assume
they're using the same hardware lock.

Usually boards have a single hwspinlock device, which provides several
hwspinlocks, and in this case, they can be trivially numbered 0 to
(num-of-locks - 1).

In case boards have several hwspinlocks devices, a different base id
should be used for each hwspinlock device (they can't all use 0 as
a starting id!).

While this is certainly not common, it's just plain wrong to just
silently use 0 as a base id whenever the hwspinlock driver is probed.

This patch provides a hwspinlock_pdata structure, that boards can use
to set a different base id for each of the hwspinlock devices they may
have, and demonstrates how to use it with the omap hwspinlock driver.

While we're at it, make sure the hwspinlock core prints an explicit
error message in case an hwspinlock is registered with an id number
that already exists; this will help users catch such base id issues.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Tony Lindgren <tony@atomide.com>
2011-09-21 19:45:32 +03:00
Ohad Ben-Cohen e467b64214 hwspinlock/core: simplify 'owner' handling
Use struct device_driver's owner member instead of asking drivers to
explicitly pass the owner again.

This simplifies drivers and also save some memory, since there's no
point now in maintaining a separate owner pointer per hwspinlock.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
2011-09-21 19:45:32 +03:00
Ohad Ben-Cohen bd9a4c7df2 drivers: hwspinlock: add framework
Add a platform-independent hwspinlock framework.

Hardware spinlock devices are needed, e.g., in order to access data
that is shared between remote processors, that otherwise have no
alternative mechanism to accomplish synchronization and mutual exclusion
operations.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Hari Kanigeri <h-kanigeri2@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2011-02-17 09:52:03 -08:00