diff options
| author | Hiro Sugawara <hsugawara@nvidia.com> | 2011-09-01 14:04:25 -0700 |
|---|---|---|
| committer | Dan Willemsen <dwillemsen@nvidia.com> | 2011-11-30 21:48:52 -0800 |
| commit | a658edf17a0b2dd2a77c4e753154cc96dd007a31 (patch) | |
| tree | 8ebcc8db85e7c1feac28f29b15a0e98bee54768e | |
| parent | bd260e07436ccdd85275cf0eeb42e49c226e0ddb (diff) | |
arm: tegra: iovmm: Remove unnecessary and harmful lock in IOVMM
Bug 862658
Reverting to K36 code.
Google invented the lock (originally as spinlock). The lock surrounds
a read-only list and is not only unnecessary but also affects
atomicity of lower layers. Should real protection be necessary in
a lower layer, the layer would be responsible for the proetection.
The SMMU layer does not need protection.
Change-Id: I45641cfde3eebc536f57d14db447b03f4ea814b5
Reviewed-on: http://git-master/r/50349
Tested-by: Hiro Sugawara <hsugawara@nvidia.com>
Reviewed-by: Scott Williams <scwilliams@nvidia.com>
Rebase-Id: R9c0fdcdbc673c0ba353a8d0731dcf4e4bf3a81fa
| -rw-r--r-- | arch/arm/mach-tegra/iovmm.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/arm/mach-tegra/iovmm.c b/arch/arm/mach-tegra/iovmm.c index e792443dc377..b4b21779126c 100644 --- a/arch/arm/mach-tegra/iovmm.c +++ b/arch/arm/mach-tegra/iovmm.c @@ -75,7 +75,6 @@ struct iovmm_share_group { static LIST_HEAD(iovmm_devices); static LIST_HEAD(iovmm_groups); static DEFINE_MUTEX(iovmm_group_list_lock); -static DEFINE_MUTEX(iovmm_device_list_lock); static struct kmem_cache *iovmm_cache; static tegra_iovmm_addr_t iovmm_align_up(struct tegra_iovmm_device *dev, @@ -814,12 +813,10 @@ struct tegra_iovmm_client *tegra_iovmm_alloc_client(const char *name, kfree(grp); goto fail_lock; } - mutex_lock(&iovmm_device_list_lock); list_for_each_entry(dev, &iovmm_devices, list) { grp->domain = dev->ops->alloc_domain(dev, c); if (grp->domain) break; } - mutex_unlock(&iovmm_device_list_lock); if (!grp->domain) { pr_err("%s: alloc_domain failed for %s\n", __func__, c->name); @@ -887,7 +884,6 @@ static int tegra_iovmm_suspend(void) struct tegra_iovmm_device *dev; unsigned long flags; - mutex_lock(&iovmm_device_list_lock); list_for_each_entry(dev, &iovmm_devices, list) { if (!dev->ops->suspend) @@ -897,11 +893,9 @@ static int tegra_iovmm_suspend(void) if (rc) { pr_err("%s: %s suspend returned %d\n", __func__, dev->name, rc); - mutex_unlock(&iovmm_device_list_lock); return rc; } } - mutex_unlock(&iovmm_device_list_lock); return 0; } @@ -910,14 +904,10 @@ static void tegra_iovmm_resume(void) struct tegra_iovmm_device *dev; unsigned long flags; - mutex_lock(&iovmm_device_list_lock); - list_for_each_entry(dev, &iovmm_devices, list) { if (dev->ops->resume) dev->ops->resume(dev); } - - mutex_unlock(&iovmm_device_list_lock); } static struct syscore_ops tegra_iovmm_syscore_ops = { |