Re: [PATCH v2] iommu/iova: Separate out rcache init

From: John Garry
Date: Mon Feb 14 2022 - 08:26:24 EST

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On 03/02/2022 11:34, Michael S. Tsirkin wrote:

On Thu, Feb 03, 2022 at 05:59:20PM +0800, John Garry wrote:

Currently the rcache structures are allocated for all IOVA domains, even if
they do not use "fast" alloc+free interface. This is wasteful of memory.

In addition, fails in init_iova_rcaches() are not handled safely, which is
less than ideal.

Make "fast" users call a separate rcache init explicitly, which includes
error checking.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>

virtio things:

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

Cheers

Hi Robin,

Can you kindly give this your blessing if you are happy with it?

Thanks!

---
Differences to v1:
- Drop stubs for iova_domain_init_rcaches() and iova_domain_free_rcaches()
- Use put_iova_domain() in vdpa code

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index d85d54f2b549..b22034975301 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -525,6 +525,7 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
struct iommu_dma_cookie *cookie = domain->iova_cookie;
unsigned long order, base_pfn;
struct iova_domain *iovad;
+ int ret;
if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
return -EINVAL;
@@ -559,6 +560,9 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
}
init_iova_domain(iovad, 1UL << order, base_pfn);
+ ret = iova_domain_init_rcaches(iovad);
+ if (ret)
+ return ret;
/* If the FQ fails we can simply fall back to strict mode */
if (domain->type == IOMMU_DOMAIN_DMA_FQ && iommu_dma_init_fq(domain))
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b28c9435b898..7e9c3a97c040 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -15,13 +15,14 @@
/* The anchor node sits above the top of the usable address space */
#define IOVA_ANCHOR ~0UL
+#define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA range size (in pages) */
+
static bool iova_rcache_insert(struct iova_domain *iovad,
unsigned long pfn,
unsigned long size);
static unsigned long iova_rcache_get(struct iova_domain *iovad,
unsigned long size,
unsigned long limit_pfn);
-static void init_iova_rcaches(struct iova_domain *iovad);
static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad);
static void free_iova_rcaches(struct iova_domain *iovad);
@@ -64,8 +65,6 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR;
rb_link_node(&iovad->anchor.node, NULL, &iovad->rbroot.rb_node);
rb_insert_color(&iovad->anchor.node, &iovad->rbroot);
- cpuhp_state_add_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD, &iovad->cpuhp_dead);
- init_iova_rcaches(iovad);
}
EXPORT_SYMBOL_GPL(init_iova_domain);
@@ -488,6 +487,13 @@ free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
}
EXPORT_SYMBOL_GPL(free_iova_fast);
+static void iova_domain_free_rcaches(struct iova_domain *iovad)
+{
+ cpuhp_state_remove_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
+ &iovad->cpuhp_dead);
+ free_iova_rcaches(iovad);
+}
+
/**
* put_iova_domain - destroys the iova domain
* @iovad: - iova domain in question.
@@ -497,9 +503,9 @@ void put_iova_domain(struct iova_domain *iovad)
{
struct iova *iova, *tmp;
- cpuhp_state_remove_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
- &iovad->cpuhp_dead);
- free_iova_rcaches(iovad);
+ if (iovad->rcaches)
+ iova_domain_free_rcaches(iovad);
+
rbtree_postorder_for_each_entry_safe(iova, tmp, &iovad->rbroot, node)
free_iova_mem(iova);
}
@@ -608,6 +614,7 @@ EXPORT_SYMBOL_GPL(reserve_iova);
*/
#define IOVA_MAG_SIZE 128
+#define MAX_GLOBAL_MAGS 32 /* magazines per bin */
struct iova_magazine {
unsigned long size;
@@ -620,6 +627,13 @@ struct iova_cpu_rcache {
struct iova_magazine *prev;
};
+struct iova_rcache {
+ spinlock_t lock;
+ unsigned long depot_size;
+ struct iova_magazine *depot[MAX_GLOBAL_MAGS];
+ struct iova_cpu_rcache __percpu *cpu_rcaches;
+};
+
static struct iova_magazine *iova_magazine_alloc(gfp_t flags)
{
return kzalloc(sizeof(struct iova_magazine), flags);
@@ -693,28 +707,54 @@ static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
mag->pfns[mag->size++] = pfn;
}
-static void init_iova_rcaches(struct iova_domain *iovad)
+int iova_domain_init_rcaches(struct iova_domain *iovad)
{
- struct iova_cpu_rcache *cpu_rcache;
- struct iova_rcache *rcache;
unsigned int cpu;
- int i;
+ int i, ret;
+
+ iovad->rcaches = kcalloc(IOVA_RANGE_CACHE_MAX_SIZE,
+ sizeof(struct iova_rcache),
+ GFP_KERNEL);
+ if (!iovad->rcaches)
+ return -ENOMEM;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
+ struct iova_cpu_rcache *cpu_rcache;
+ struct iova_rcache *rcache;
+
rcache = &iovad->rcaches[i];
spin_lock_init(&rcache->lock);
rcache->depot_size = 0;
- rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache), cache_line_size());
- if (WARN_ON(!rcache->cpu_rcaches))
- continue;
+ rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache),
+ cache_line_size());
+ if (!rcache->cpu_rcaches) {
+ ret = -ENOMEM;
+ goto out_err;
+ }
for_each_possible_cpu(cpu) {
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
+
spin_lock_init(&cpu_rcache->lock);
cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL);
cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL);
+ if (!cpu_rcache->loaded || !cpu_rcache->prev) {
+ ret = -ENOMEM;
+ goto out_err;
+ }
}
}
+
+ ret = cpuhp_state_add_instance_nocalls(CPUHP_IOMMU_IOVA_DEAD,
+ &iovad->cpuhp_dead);
+ if (ret)
+ goto out_err;
+ return 0;
+
+out_err:
+ free_iova_rcaches(iovad);
+ return ret;
}
+EXPORT_SYMBOL_GPL(iova_domain_init_rcaches);
/*
* Try inserting IOVA range starting with 'iova_pfn' into 'rcache', and
@@ -831,7 +871,7 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad,
{
unsigned int log_size = order_base_2(size);
- if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
+ if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE || !iovad->rcaches)
return 0;
return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn - size);
@@ -849,6 +889,8 @@ static void free_iova_rcaches(struct iova_domain *iovad)
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
+ if (!rcache->cpu_rcaches)
+ break;
for_each_possible_cpu(cpu) {
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
iova_magazine_free(cpu_rcache->loaded);
@@ -858,6 +900,9 @@ static void free_iova_rcaches(struct iova_domain *iovad)
for (j = 0; j < rcache->depot_size; ++j)
iova_magazine_free(rcache->depot[j]);
}
+
+ kfree(iovad->rcaches);
+ iovad->rcaches = NULL;
}
/*
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 2b1143f11d8f..22f7d43f8a68 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -480,6 +480,7 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
struct file *file;
struct vduse_bounce_map *map;
unsigned long pfn, bounce_pfns;
+ int ret;
bounce_pfns = PAGE_ALIGN(bounce_size) >> PAGE_SHIFT;
if (iova_limit <= bounce_size)
@@ -513,10 +514,20 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size)
spin_lock_init(&domain->iotlb_lock);
init_iova_domain(&domain->stream_iovad,
PAGE_SIZE, IOVA_START_PFN);
+ ret = iova_domain_init_rcaches(&domain->stream_iovad);
+ if (ret)
+ goto err_iovad_stream;
init_iova_domain(&domain->consistent_iovad,
PAGE_SIZE, bounce_pfns);
+ ret = iova_domain_init_rcaches(&domain->consistent_iovad);
+ if (ret)
+ goto err_iovad_consistent;
return domain;
+err_iovad_consistent:
+ put_iova_domain(&domain->stream_iovad);
+err_iovad_stream:
+ fput(file);
err_file:
vfree(domain->bounce_maps);
err_map:
diff --git a/include/linux/iova.h b/include/linux/iova.h
index cea79cb9f26c..320a70e40233 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -21,18 +21,8 @@ struct iova {
unsigned long pfn_lo; /* Lowest allocated pfn */
};
-struct iova_magazine;
-struct iova_cpu_rcache;
-#define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA range size (in pages) */
-#define MAX_GLOBAL_MAGS 32 /* magazines per bin */
-
-struct iova_rcache {
- spinlock_t lock;
- unsigned long depot_size;
- struct iova_magazine *depot[MAX_GLOBAL_MAGS];
- struct iova_cpu_rcache __percpu *cpu_rcaches;
-};
+struct iova_rcache;
/* holds all the iova translations for a domain */
struct iova_domain {
@@ -46,7 +36,7 @@ struct iova_domain {
unsigned long max32_alloc_size; /* Size of last failed allocation */
struct iova anchor; /* rbtree lookup anchor */
- struct iova_rcache rcaches[IOVA_RANGE_CACHE_MAX_SIZE]; /* IOVA range caches */
+ struct iova_rcache *rcaches;
struct hlist_node cpuhp_dead;
};
@@ -102,6 +92,7 @@ struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
unsigned long pfn_hi);
void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
unsigned long start_pfn);
+int iova_domain_init_rcaches(struct iova_domain *iovad);
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
void put_iova_domain(struct iova_domain *iovad);
#else
--
2.26.2

.

Next message: Oded Gabbay: "[PATCH v2 2/2] habanalabs: allow user to set allocation page size"
Previous message: Jason Gunthorpe: "Re: [PATCH v3 09/10] iommu: Use dev_iommu_ops() helper"
Next in thread: Robin Murphy: "Re: [PATCH v2] iommu/iova: Separate out rcache init"
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