[PATCH 19/30] habanalabs: don't free phys_pg_pack inside lock

From: Oded Gabbay
Date: Sat Jan 22 2022 - 14:58:34 EST


Freeing phys_pg_pack includes calling to scrubbing functions of the
device's memory, taking locks and possibly even calling reset.

This is not something that should be done while holding a device-wide
spinlock.

Therefore, save the relevant objects on a local linked-list and after
releasing the spinlock, traverse that list and free the phys_pg_pack
objects.

Signed-off-by: Oded Gabbay <ogabbay@xxxxxxxxxx>
---
drivers/misc/habanalabs/common/habanalabs.h | 3 +++
drivers/misc/habanalabs/common/memory.c | 16 +++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/habanalabs/common/habanalabs.h b/drivers/misc/habanalabs/common/habanalabs.h
index 6c7a60210416..9c8374d88907 100644
--- a/drivers/misc/habanalabs/common/habanalabs.h
+++ b/drivers/misc/habanalabs/common/habanalabs.h
@@ -1738,6 +1738,8 @@ struct hl_vm_hw_block_list_node {
* @pages: the physical page array.
* @npages: num physical pages in the pack.
* @total_size: total size of all the pages in this list.
+ * @node: used to attach to deletion list that is used when all the allocations are cleared
+ * at the teardown of the context.
* @mapping_cnt: number of shared mappings.
* @exporting_cnt: number of dma-buf exporting.
* @asid: the context related to this list.
@@ -1753,6 +1755,7 @@ struct hl_vm_phys_pg_pack {
u64 *pages;
u64 npages;
u64 total_size;
+ struct list_head node;
atomic_t mapping_cnt;
u32 exporting_cnt;
u32 asid;
diff --git a/drivers/misc/habanalabs/common/memory.c b/drivers/misc/habanalabs/common/memory.c
index c1eefaebacb6..4a5d3a179765 100644
--- a/drivers/misc/habanalabs/common/memory.c
+++ b/drivers/misc/habanalabs/common/memory.c
@@ -2607,11 +2607,12 @@ int hl_vm_ctx_init(struct hl_ctx *ctx)
*/
void hl_vm_ctx_fini(struct hl_ctx *ctx)
{
- struct hl_device *hdev = ctx->hdev;
- struct hl_vm *vm = &hdev->vm;
struct hl_vm_phys_pg_pack *phys_pg_list;
+ struct hl_device *hdev = ctx->hdev;
struct hl_vm_hash_node *hnode;
+ struct hl_vm *vm = &hdev->vm;
struct hlist_node *tmp_node;
+ struct list_head free_list;
struct hl_mem_in args;
int i;

@@ -2644,19 +2645,24 @@ void hl_vm_ctx_fini(struct hl_ctx *ctx)

mutex_unlock(&ctx->mmu_lock);

+ INIT_LIST_HEAD(&free_list);
+
spin_lock(&vm->idr_lock);
idr_for_each_entry(&vm->phys_pg_pack_handles, phys_pg_list, i)
if (phys_pg_list->asid == ctx->asid) {
dev_dbg(hdev->dev,
"page list 0x%px of asid %d is still alive\n",
phys_pg_list, ctx->asid);
- atomic64_sub(phys_pg_list->total_size,
- &hdev->dram_used_mem);
- free_phys_pg_pack(hdev, phys_pg_list);
+
+ atomic64_sub(phys_pg_list->total_size, &hdev->dram_used_mem);
idr_remove(&vm->phys_pg_pack_handles, i);
+ list_add(&phys_pg_list->node, &free_list);
}
spin_unlock(&vm->idr_lock);

+ list_for_each_entry(phys_pg_list, &free_list, node)
+ free_phys_pg_pack(hdev, phys_pg_list);
+
va_range_fini(hdev, ctx->va_range[HL_VA_RANGE_TYPE_DRAM]);
va_range_fini(hdev, ctx->va_range[HL_VA_RANGE_TYPE_HOST]);

--
2.25.1