evie/android_kernel_oneplus_msm8998
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msm: kgsl: Reserve a context ID slot but don't populate immediately

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When creating a context allocate an ID but don't populate the slot
with the context pointer until we are done setup up the rest of the
process. This avoids a race if somebody tries to free the same
identifier before the create operation is complete.

Change-Id: Ic0dedbadca5b4cc4ce567afad48a33078b549439
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Dumpeti Sathish Kumar <sathyanov14@codeaurora.org>
This commit is contained in:
Jordan Crouse 2016-05-31 11:24:22 -06:00 • committed by Dumpeti Sathish Kumar
parent 04947ea3d8
commit eed663a48b
1 changed files with 13 additions and 8 deletions
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21
drivers/gpu/msm/kgsl.c
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@ -491,21 +491,18 @@ void kgsl_context_dump(struct kgsl_context *context)
EXPORT_SYMBOL(kgsl_context_dump);
/* Allocate a new context ID */
static int _kgsl_get_context_id(struct kgsl_device *device,
struct kgsl_context *context)
static int _kgsl_get_context_id(struct kgsl_device *device)
{
int id;
idr_preload(GFP_KERNEL);
write_lock(&device->context_lock);
id = idr_alloc(&device->context_idr, context, 1,
/* Allocate the slot but don't put a pointer in it yet */
id = idr_alloc(&device->context_idr, NULL, 1,
KGSL_MEMSTORE_MAX, GFP_NOWAIT);
write_unlock(&device->context_lock);
idr_preload_end();
if (id > 0)
context->id = id;
return id;
}
@ -529,7 +526,7 @@ int kgsl_context_init(struct kgsl_device_private *dev_priv,
char name[64];
int ret = 0, id;
id = _kgsl_get_context_id(device, context);
id = _kgsl_get_context_id(device);
if (id == -ENOSPC) {
/*
* Before declaring that there are no contexts left try
@ -538,7 +535,7 @@ int kgsl_context_init(struct kgsl_device_private *dev_priv,
*/
flush_workqueue(device->events_wq);
id = _kgsl_get_context_id(device, context);
id = _kgsl_get_context_id(device);
}
if (id < 0) {
@ -550,6 +547,8 @@ int kgsl_context_init(struct kgsl_device_private *dev_priv,
return id;
}
context->id = id;
kref_init(&context->refcount);
/*
* Get a refernce to the process private so its not destroyed, until
@ -1733,6 +1732,12 @@ long kgsl_ioctl_drawctxt_create(struct kgsl_device_private *dev_priv,
goto done;
}
trace_kgsl_context_create(dev_priv->device, context, param->flags);
/* Commit the pointer to the context in context_idr */
write_lock(&device->context_lock);
idr_replace(&device->context_idr, context, context->id);
write_unlock(&device->context_lock);
param->drawctxt_id = context->id;
done:
return result;