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); _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu