Messages in this thread Patch in this message | | | Date | Thu, 2 Mar 2023 21:52:42 +0800 | Subject | Re: [PATCH v4 3/6] iommu/sva: Stop using ioasid_set for SVA | From | Tina Zhang <> |
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Hi,
On 3/2/23 07:56, Jacob Pan wrote: > From: Jason Gunthorpe <jgg@nvidia.com> > > Instead SVA drivers can use a simple global IDA to allocate PASIDs for > each mm_struct. > > Future work would be to allow drivers using the SVA APIs to reserve global > PASIDs from this IDA for their internal use, eg with the DMA API PASID > support. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > --- > v4: > - Keep GFP_ATOMIC flag for PASID allocation, will changed to > GFP_KERNEL in a separate patch. > --- > drivers/iommu/iommu-sva.c | 62 ++++++++++----------------------------- > drivers/iommu/iommu-sva.h | 3 -- > 2 files changed, 15 insertions(+), 50 deletions(-) > > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c > index 376b2a9e2543..297852ae5e7c 100644 > --- a/drivers/iommu/iommu-sva.c > +++ b/drivers/iommu/iommu-sva.c > @@ -9,26 +9,13 @@ > #include "iommu-sva.h" > > static DEFINE_MUTEX(iommu_sva_lock); > -static DECLARE_IOASID_SET(iommu_sva_pasid); > +static DEFINE_IDA(iommu_global_pasid_ida); > > -/** > - * iommu_sva_alloc_pasid - Allocate a PASID for the mm > - * @mm: the mm > - * @min: minimum PASID value (inclusive) > - * @max: maximum PASID value (inclusive) > - * > - * Try to allocate a PASID for this mm, or take a reference to the existing one > - * provided it fits within the [@min, @max] range. On success the PASID is > - * available in mm->pasid and will be available for the lifetime of the mm. > - * > - * Returns 0 on success and < 0 on error. > - */ > -int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) > +static int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) > { > - int ret = 0; > - ioasid_t pasid; > + int ret; > > - if (min == INVALID_IOASID || max == INVALID_IOASID || > + if (min == IOMMU_PASID_INVALID || max == IOMMU_PASID_INVALID || > min == 0 || max < min) > return -EINVAL; > > @@ -37,39 +24,20 @@ int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) > if (pasid_valid(mm->pasid)) { > if (mm->pasid < min || mm->pasid >= max) Here seems not right, since the valid range is defined [min, max]. Shouldn't the invalid range be: if (mm->pasid < min || mm->pasid > max)
Regards, -Tina
> ret = -EOVERFLOW; > + else > + ret = 0; > goto out; > } > > - pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm); > - if (!pasid_valid(pasid)) > - ret = -ENOMEM; > - else > - mm->pasid = ret; > + ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_ATOMIC); > + if (ret < min) > + goto out; > + mm->pasid = ret; > + ret = 0; > out: > mutex_unlock(&iommu_sva_lock); > return ret; > } > -EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid); > - > -/* ioasid_find getter() requires a void * argument */ > -static bool __mmget_not_zero(void *mm) > -{ > - return mmget_not_zero(mm); > -} > - > -/** > - * iommu_sva_find() - Find mm associated to the given PASID > - * @pasid: Process Address Space ID assigned to the mm > - * > - * On success a reference to the mm is taken, and must be released with mmput(). > - * > - * Returns the mm corresponding to this PASID, or an error if not found. > - */ > -struct mm_struct *iommu_sva_find(ioasid_t pasid) > -{ > - return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero); > -} > -EXPORT_SYMBOL_GPL(iommu_sva_find); > > /** > * iommu_sva_bind_device() - Bind a process address space to a device > @@ -241,8 +209,8 @@ iommu_sva_handle_iopf(struct iommu_fault *fault, void *data) > > void mm_pasid_drop(struct mm_struct *mm) > { > - if (pasid_valid(mm->pasid)) { > - ioasid_free(mm->pasid); > - mm->pasid = INVALID_IOASID; > - } > + if (likely(!pasid_valid(mm->pasid))) > + return; > + > + ida_free(&iommu_global_pasid_ida, mm->pasid); > } > diff --git a/drivers/iommu/iommu-sva.h b/drivers/iommu/iommu-sva.h > index 7215a761b962..c22d0174ad61 100644 > --- a/drivers/iommu/iommu-sva.h > +++ b/drivers/iommu/iommu-sva.h > @@ -8,9 +8,6 @@ > #include <linux/ioasid.h> > #include <linux/mm_types.h> > > -int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max); > -struct mm_struct *iommu_sva_find(ioasid_t pasid); > - > /* I/O Page fault */ > struct device; > struct iommu_fault;
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