Re: [PATCH 1/3] iommu/arm-smmu: Move to bitmap for arm_smmu_domain atrributes

[Robin Murphy]

On 21/01/2019 05:53, Vivek Gautam wrote:

A number of arm_smmu_domain's attributes can be assigned based
on the iommu domains's attributes. These local attributes better
be managed by a bitmap.
So remove boolean flags and move to a 32-bit bitmap, and enable
each bits separtely.

Signed-off-by: Vivek Gautam <vivek.gau...@codeaurora.org>
---
  drivers/iommu/arm-smmu.c | 10 ++++++----
  1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 7ebbcf1b2eb3..52b300dfc096 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -257,10 +257,11 @@ struct arm_smmu_domain {
        const struct iommu_gather_ops   *tlb_ops;
        struct arm_smmu_cfg             cfg;
        enum arm_smmu_domain_stage      stage;
-       bool                            non_strict;
        struct mutex                    init_mutex; /* Protects smmu pointer */
        spinlock_t                      cb_lock; /* Serialises ATS1* ops and 
TLB syncs */
        struct iommu_domain             domain;
+#define ARM_SMMU_DOMAIN_ATTR_NON_STRICT        BIT(0)
+       unsigned int                    attr;
  };

struct arm_smmu_option_prop {

@@ -901,7 +902,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain 
*domain,
        if (smmu->features & ARM_SMMU_FEAT_COHERENT_WALK)
                pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;

- if (smmu_domain->non_strict)

+       if (smmu_domain->attr & ARM_SMMU_DOMAIN_ATTR_NON_STRICT)
                pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;

/* Non coherent page table mappings only for Stage-1 */

@@ -1598,7 +1599,8 @@ static int arm_smmu_domain_get_attr(struct iommu_domain 
*domain,
        case IOMMU_DOMAIN_DMA:
                switch (attr) {
                case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
-                       *(int *)data = smmu_domain->non_strict;
+                       *(int *)data = !!(smmu_domain->attr &
+                                         ARM_SMMU_DOMAIN_ATTR_NON_STRICT);
                        return 0;
                default:
                        return -ENODEV;
@@ -1638,7 +1640,7 @@ static int arm_smmu_domain_set_attr(struct iommu_domain 
*domain,
        case IOMMU_DOMAIN_DMA:
                switch (attr) {
                case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
-                       smmu_domain->non_strict = *(int *)data;
+                       smmu_domain->attr |= ARM_SMMU_DOMAIN_ATTR_NON_STRICT;

But what if *data == 0?

Robin.

                        break;
                default:
                        ret = -ENODEV;