Messages in this thread |  | | From | "Mehta, Sohil" <> | Subject | Re: [PATCH v3 2/2] iommu/amd: Add basic debugfs infrastructure for AMD IOMMU | Date | Wed, 18 Apr 2018 07:27:28 +0000 |
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On Wed, 2018-04-18 at 05:58 +0000, Yang, Shunyong wrote: > Hi, Gary and Sohil, > > On Tue, 2018-04-17 at 13:38 -0400, Hook, Gary wrote: > > On 4/13/2018 8:08 PM, Mehta, Sohil wrote: > > > > > > On Fri, 2018-04-06 at 08:17 -0500, Gary R Hook wrote: > > > > > > > > > > > > + > > > > +void amd_iommu_debugfs_setup(struct amd_iommu *iommu) > > > > +{ > > > > + char name[MAX_NAME_LEN + 1]; > > > > + struct dentry *d_top; > > > > + > > > > + if (!debugfs_initialized()) > > > Probably not needed. > > Right. > > When will this check is needed? > IMO, this function is to check debugfs ready status before we want to > use debugfs. I just want to understand when we should use > debugfs_initialized(); >
You are right debugfs_initialized() can be used to check if debugfs is ready. However in this case we can also rely on debugfs_create_dir() which is called in iommu_debufs_setup().
debugfs_create_dir() says:
* If debugfs is not enabled in the kernel, the value -%ENODEV will be * returned.
Sohil
> Thanks. > Shunyong. > > > > > > > > > > > > > > > > > + return; > > > > + > > > > + mutex_lock(&amd_iommu_debugfs_lock); > > > > + if (!amd_iommu_debugfs) { > > > > + d_top = iommu_debugfs_setup(); > > > > + if (d_top) > > > > + amd_iommu_debugfs = > > > > debugfs_create_dir("amd", d_top); > > > > + } > > > > + mutex_unlock(&amd_iommu_debugfs_lock); |  |