diff options
| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2017-03-22 15:21:50 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-03-30 21:42:11 +1100 |
| commit | e5afdf9dd515a9446c009f44f99f9bc2f91b89a7 (patch) | |
| tree | 21683e5afe296b2a6cf32e22f5471b1da1a7a18e /arch/powerpc/kernel/iommu.c | |
| parent | 11edf116e3a6352cfee6b1437d41603c9aff79c9 (diff) | |
powerpc/vfio_spapr_tce: Add reference counting to iommu_table
So far iommu_table obejcts were only used in virtual mode and had
a single owner. We are going to change this by implementing in-kernel
acceleration of DMA mapping requests. The proposed acceleration
will handle requests in real mode and KVM will keep references to tables.
This adds a kref to iommu_table and defines new helpers to update it.
This replaces iommu_free_table() with iommu_tce_table_put() and makes
iommu_free_table() static. iommu_tce_table_get() is not used in this patch
but it will be in the following patch.
Since this touches prototypes, this also removes @node_name parameter as
it has never been really useful on powernv and carrying it for
the pseries platform code to iommu_free_table() seems to be quite
useless as well.
This should cause no behavioral change.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/iommu.c')
| -rw-r--r-- | arch/powerpc/kernel/iommu.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index a3689fdedd4a..5a3231fedf08 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -711,13 +711,13 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid) return tbl; } -void iommu_free_table(struct iommu_table *tbl, const char *node_name) +static void iommu_table_free(struct kref *kref) { unsigned long bitmap_sz; unsigned int order; + struct iommu_table *tbl; - if (!tbl) - return; + tbl = container_of(kref, struct iommu_table, it_kref); if (tbl->it_ops->free) tbl->it_ops->free(tbl); @@ -736,7 +736,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name) /* verify that table contains no entries */ if (!bitmap_empty(tbl->it_map, tbl->it_size)) - pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name); + pr_warn("%s: Unexpected TCEs\n", __func__); /* calculate bitmap size in bytes */ bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long); @@ -748,7 +748,24 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name) /* free table */ kfree(tbl); } -EXPORT_SYMBOL_GPL(iommu_free_table); + +struct iommu_table *iommu_tce_table_get(struct iommu_table *tbl) +{ + if (kref_get_unless_zero(&tbl->it_kref)) + return tbl; + + return NULL; +} +EXPORT_SYMBOL_GPL(iommu_tce_table_get); + +int iommu_tce_table_put(struct iommu_table *tbl) +{ + if (WARN_ON(!tbl)) + return 0; + + return kref_put(&tbl->it_kref, iommu_table_free); +} +EXPORT_SYMBOL_GPL(iommu_tce_table_put); /* Creates TCEs for a user provided buffer. The user buffer must be * contiguous real kernel storage (not vmalloc). The address passed here |