Messages in this thread | | | Date | Fri, 10 Mar 2023 13:07:51 +0800 | Subject | Re: [PATCH v5 4/7] iommu/sva: Stop using ioasid_set for SVA | From | Baolu Lu <> |
| |
On 3/10/23 6:21 AM, 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> > --- > v5: > - Put removing iommu_sva_find() to a separate patch (Kevin) > - Make pasid allocation range to be inclusive (Tina) > - Simplified return code handling (Baolu) > v4: > - Keep GFP_ATOMIC flag for PASID allocation, will changed to > GFP_KERNEL in a separate patch. > --- > drivers/iommu/iommu-sva.c | 42 +++++++++++++-------------------------- > drivers/iommu/iommu-sva.h | 2 -- > 2 files changed, 14 insertions(+), 30 deletions(-) > > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c > index 4f357ef14f04..b75711bdbe97 100644 > --- a/drivers/iommu/iommu-sva.c > +++ b/drivers/iommu/iommu-sva.c > @@ -9,47 +9,33 @@ > #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; > > - if (min == INVALID_IOASID || max == INVALID_IOASID || > - min == 0 || max < min) > + if (!pasid_valid(min) || !pasid_valid(max) || > + min == 0 || max < min)
No need to change above line.
> return -EINVAL; > > mutex_lock(&iommu_sva_lock); > /* Is a PASID already associated with this mm? */ > if (pasid_valid(mm->pasid)) { > - if (mm->pasid < min || mm->pasid >= max) > + if (mm->pasid < min || mm->pasid > max)
I forgot why do we need to change above line. But it's better to put some comments there so that people don't need to dive into ioasid_alloc() to know the inclusion or exclusion of @min or @max.
> ret = -EOVERFLOW; > goto out; > } > > - pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm); > - if (!pasid_valid(pasid)) > - ret = -ENOMEM; > - else > - mm->pasid = pasid; > + ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_ATOMIC); > + if (ret < 0) > + goto out; > + mm->pasid = ret; > + ret = 0; > out: > mutex_unlock(&iommu_sva_lock); > return ret; > } > -EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid); > > /** > * iommu_sva_bind_device() - Bind a process address space to a device > @@ -221,8 +207,8 @@ 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);
Any reason why do you drop "mm->pasid = INVALID_IOASID;" here?
> } > diff --git a/drivers/iommu/iommu-sva.h b/drivers/iommu/iommu-sva.h > index 102eae1817a2..c22d0174ad61 100644 > --- a/drivers/iommu/iommu-sva.h > +++ b/drivers/iommu/iommu-sva.h > @@ -8,8 +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); > - > /* I/O Page fault */ > struct device; > struct iommu_fault;
Best regards, baolu
| |