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| author | Lucas De Marchi <lucas.demarchi@intel.com> | 2019-11-16 02:15:39 +0100 |
|---|---|---|
| committer | Lucas De Marchi <lucas.demarchi@intel.com> | 2019-11-18 22:27:09 +0100 |
| commit | ac4eead3796579bdadd12e2fa99c4ddc920eda30 (patch) | |
| tree | de35c9ccbcf48b1aeaeb9c9536c99dd7ac3e3ce1 /drivers/gpu/drm/i915/display/intel_dsb.h | |
| parent | drm/i915/mst: Check uapi enable not intel one during mst atomic check (diff) | |
| download | linux-ac4eead3796579bdadd12e2fa99c4ddc920eda30.tar.xz linux-ac4eead3796579bdadd12e2fa99c4ddc920eda30.zip | |
drm/i915/dsb: remove atomic operations
The current dsb API is not really prepared to handle multithread access.
I was debugging an issue that ended up fixed by commit a096883dda2c
("drm/i915/dsb: Remove PIN_MAPPABLE from the DSB object VMA") and was
puzzled how these atomic operations were guaranteeing atomicity.
if (atomic_add_return(1, &dsb->refcount) != 1)
return dsb;
Thread A could still be initializing dsb struct (and even fail in the
middle) while thread B would take a reference and use it (even
derefencing a NULL cmd_buf).
I don't think the atomic operations here will help much if this were
to support multithreaded scenario in future, so just remove them to
avoid confusion.
v2: Use refcount++ != 0 instead of ++refcount != 1 (from Ville)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191111205024.22853-2-lucas.demarchi@intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20191116011539.18230-1-lucas.demarchi@intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_dsb.h')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dsb.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h index 6f95c8e909e6..395ef9ce558e 100644 --- a/drivers/gpu/drm/i915/display/intel_dsb.h +++ b/drivers/gpu/drm/i915/display/intel_dsb.h @@ -22,7 +22,7 @@ enum dsb_id { }; struct intel_dsb { - atomic_t refcount; + long refcount; enum dsb_id id; u32 *cmd_buf; struct i915_vma *vma; |