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drm/i915: Nuke struct_mutex from context_setparam 

Userspace should be free to race against itself and shoot itself in
the foot if it so desires to adjust a parameter at the same time as
submitting a batch to that context. As such, the struct_mutex in context
setparam is only being used to serialise userspace against itself and
not for any protection of internal structs and so is superfluous.

v2: Separate user_flags from internal flags to reduce chance of
interference; and use locked bit ops for user updates.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180911132206.23032-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2018-09-11 14:22:06 +01:00
parent 146cdf3fad
commit d3f3e5e438
3 changed files with 27 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/gpu/drm/i915/i915_gem_context.c
View File

@ -862,7 +862,7 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
ret = -EINVAL;
break;
case I915_CONTEXT_PARAM_NO_ZEROMAP:
args->value = ctx->flags & CONTEXT_NO_ZEROMAP;
args->value = test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
break;
case I915_CONTEXT_PARAM_GTT_SIZE:
if (ctx->ppgtt)
@ -896,27 +896,23 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
struct drm_i915_file_private *file_priv = file->driver_priv;
struct drm_i915_gem_context_param *args = data;
struct i915_gem_context *ctx;
int ret;
int ret = 0;
ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
if (!ctx)
return -ENOENT;
ret = i915_mutex_lock_interruptible(dev);
if (ret)
goto out;
switch (args->param) {
case I915_CONTEXT_PARAM_BAN_PERIOD:
ret = -EINVAL;
break;
case I915_CONTEXT_PARAM_NO_ZEROMAP:
if (args->size) {
if (args->size)
ret = -EINVAL;
} else {
ctx->flags &= ~CONTEXT_NO_ZEROMAP;
ctx->flags |= args->value ? CONTEXT_NO_ZEROMAP : 0;
}
else if (args->value)
set_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
else
clear_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
break;
case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
if (args->size)
@ -960,9 +956,7 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
ret = -EINVAL;
break;
}
mutex_unlock(&dev->struct_mutex);
out:
i915_gem_context_put(ctx);
return ret;
}

33
drivers/gpu/drm/i915/i915_gem_context.h
View File

@ -116,16 +116,21 @@ struct i915_gem_context {
*/
struct rcu_head rcu;
/**
* @user_flags: small set of booleans controlled by the user
*/
unsigned long user_flags;
#define UCONTEXT_NO_ZEROMAP 0
#define UCONTEXT_NO_ERROR_CAPTURE 1
#define UCONTEXT_BANNABLE 2
/**
* @flags: small set of booleans
*/
unsigned long flags;
#define CONTEXT_NO_ZEROMAP BIT(0)
#define CONTEXT_NO_ERROR_CAPTURE 1
#define CONTEXT_CLOSED 2
#define CONTEXT_BANNABLE 3
#define CONTEXT_BANNED 4
#define CONTEXT_FORCE_SINGLE_SUBMISSION 5
#define CONTEXT_BANNED 0
#define CONTEXT_CLOSED 1
#define CONTEXT_FORCE_SINGLE_SUBMISSION 2
/**
* @hw_id: - unique identifier for the context
@ -209,37 +214,37 @@ static inline bool i915_gem_context_is_closed(const struct i915_gem_context *ctx
static inline void i915_gem_context_set_closed(struct i915_gem_context *ctx)
{
GEM_BUG_ON(i915_gem_context_is_closed(ctx));
__set_bit(CONTEXT_CLOSED, &ctx->flags);
set_bit(CONTEXT_CLOSED, &ctx->flags);
}
static inline bool i915_gem_context_no_error_capture(const struct i915_gem_context *ctx)
{
return test_bit(CONTEXT_NO_ERROR_CAPTURE, &ctx->flags);
return test_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}
static inline void i915_gem_context_set_no_error_capture(struct i915_gem_context *ctx)
{
__set_bit(CONTEXT_NO_ERROR_CAPTURE, &ctx->flags);
set_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}
static inline void i915_gem_context_clear_no_error_capture(struct i915_gem_context *ctx)
{
__clear_bit(CONTEXT_NO_ERROR_CAPTURE, &ctx->flags);
clear_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}
static inline bool i915_gem_context_is_bannable(const struct i915_gem_context *ctx)
{
return test_bit(CONTEXT_BANNABLE, &ctx->flags);
return test_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}
static inline void i915_gem_context_set_bannable(struct i915_gem_context *ctx)
{
__set_bit(CONTEXT_BANNABLE, &ctx->flags);
set_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}
static inline void i915_gem_context_clear_bannable(struct i915_gem_context *ctx)
{
__clear_bit(CONTEXT_BANNABLE, &ctx->flags);
clear_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}
static inline bool i915_gem_context_is_banned(const struct i915_gem_context *ctx)
@ -249,7 +254,7 @@ static inline bool i915_gem_context_is_banned(const struct i915_gem_context *ctx
static inline void i915_gem_context_set_banned(struct i915_gem_context *ctx)
{
__set_bit(CONTEXT_BANNED, &ctx->flags);
set_bit(CONTEXT_BANNED, &ctx->flags);
}
static inline bool i915_gem_context_force_single_submission(const struct i915_gem_context *ctx)

2
drivers/gpu/drm/i915/i915_gem_execbuffer.c
View File

@ -743,7 +743,7 @@ static int eb_select_context(struct i915_execbuffer *eb)
}
eb->context_flags = 0;
if (ctx->flags & CONTEXT_NO_ZEROMAP)
if (test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags))
eb->context_flags |= __EXEC_OBJECT_NEEDS_BIAS;
return 0;