evie/android_kernel_oneplus_msm8998
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

msm: mdss: protect iommu attached status variable with iommu_lock

Browse source 
Commit dd7ad27eb3de6b088b6525b066c40f5a29ac4c60 ("msm: mdss: fix
race condition between iommu attach and sending DCS cmds") protected
the iommu attach/detach to fix possible race condition between the
display thread and DCS cmd sending from ESD or some other thread with
iommu_lock. But this still leaves possibility of race condition based
on iommu_attached status flag.
  -> Display thread finishes the attach and releases the iommu lock
  -> DCS cmd thread gets the iommu lock and checks iommu_attached
     status before display thread could change it.
Protect the iommu_attached status variable along with iommu
attach/detach to avoid such cases.

Change-Id: I42d0ced5cbfd741cf02ad71c80c4f01dde37f647
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>
Signed-off-by: Krishna Manikandan <mkrishn@codeaurora.org>
This commit is contained in:
Krishna Manikandan 2016-12-28 18:17:03 +05:30
parent 42507841e7
commit 9efdd2ca23
2 changed files with 21 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
drivers/video/fbdev/msm/mdss_smmu.c
View file

@ -177,7 +177,6 @@ static int mdss_smmu_attach_v2(struct mdss_data_type *mdata)
struct mdss_smmu_client *mdss_smmu;
int i, rc = 0;
mutex_lock(&mdp_iommu_lock);
for (i = 0; i < MDSS_IOMMU_MAX_DOMAIN; i++) {
if (!mdss_smmu_is_valid_domain_type(mdata, i))
continue;
@ -211,11 +210,9 @@ static int mdss_smmu_attach_v2(struct mdss_data_type *mdata)
}
} else {
pr_err("iommu device not attached for domain[%d]\n", i);
mutex_unlock(&mdp_iommu_lock);
return -ENODEV;
}
}
mutex_unlock(&mdp_iommu_lock);
return 0;
@ -228,7 +225,6 @@ err:
mdss_smmu->domain_attached = false;
}
}
mutex_unlock(&mdp_iommu_lock);
return rc;
}
@ -245,7 +241,6 @@ static int mdss_smmu_detach_v2(struct mdss_data_type *mdata)
struct mdss_smmu_client *mdss_smmu;
int i;
mutex_lock(&mdp_iommu_lock);
for (i = 0; i < MDSS_IOMMU_MAX_DOMAIN; i++) {
if (!mdss_smmu_is_valid_domain_type(mdata, i))
continue;
@ -270,7 +265,6 @@ static int mdss_smmu_detach_v2(struct mdss_data_type *mdata)
}
}
}
mutex_unlock(&mdp_iommu_lock);
return 0;
}

27
drivers/video/fbdev/msm/mdss_smmu.h
View file

@ -150,18 +150,26 @@ static inline int mdss_smmu_attach(struct mdss_data_type *mdata)
{
int rc;
mdata->mdss_util->iommu_lock();
MDSS_XLOG(mdata->iommu_attached);
if (mdata->iommu_attached) {
pr_debug("mdp iommu already attached\n");
return 0;
rc = 0;
goto end;
}
if (!mdata->smmu_ops.smmu_attach)
return -ENOSYS;
if (!mdata->smmu_ops.smmu_attach) {
rc = -ENODEV;
goto end;
}
rc = mdata->smmu_ops.smmu_attach(mdata);
if (!rc)
mdata->iommu_attached = true;
end:
mdata->mdss_util->iommu_unlock();
return rc;
}
@ -169,19 +177,26 @@ static inline int mdss_smmu_detach(struct mdss_data_type *mdata)
{
int rc;
mdata->mdss_util->iommu_lock();
MDSS_XLOG(mdata->iommu_attached);
if (!mdata->iommu_attached) {
pr_debug("mdp iommu already dettached\n");
return 0;
rc = 0;
goto end;
}
if (!mdata->smmu_ops.smmu_detach)
return -ENOSYS;
if (!mdata->smmu_ops.smmu_detach) {
rc = -ENODEV;
goto end;
}
rc = mdata->smmu_ops.smmu_detach(mdata);
if (!rc)
mdata->iommu_attached = false;
end:
mdata->mdss_util->iommu_unlock();
return rc;
}