[PATCH v2 10/20] nvme-auth: guarantee dhchap buffers under memory pressure

Sagi Grimberg
2022-11-13T11:26:06Z

We want to guarantee that we have chap buffers when a controller
reconnects under memory pressure. Add a mempool specifically
for that.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
drivers/nvme/host/auth.c | 30 ++++++++++++++++++++++++++++--
drivers/nvme/host/core.c | 6 ++++++
drivers/nvme/host/nvme.h | 7 +++++++
3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index 4d288333b0fd..4bfe9ecda12a 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -14,6 +14,8 @@
#include <linux/nvme-auth.h>

#define CHAP_BUF_SIZE 4096
+struct kmem_cache *nvme_chap_buf_cache;
+mempool_t *nvme_chap_buf_pool;

struct nvme_dhchap_queue_context {
struct list_head entry;
@@ -675,7 +677,7 @@ static void nvme_auth_reset_dhchap(struct nvme_dhchap_queue_context *chap)
chap->transaction = 0;
memset(chap->c1, 0, sizeof(chap->c1));
memset(chap->c2, 0, sizeof(chap->c2));
- kfree(chap->buf);
+ mempool_free(chap->buf, nvme_chap_buf_pool);
chap->buf = NULL;
}

@@ -701,7 +703,7 @@ static void nvme_queue_auth_work(struct work_struct *work)
* Allocate a large enough buffer for the entire negotiation:
* 4k is enough to ffdhe8192.
*/
- chap->buf = kmalloc(CHAP_BUF_SIZE, GFP_KERNEL);
+ chap->buf = mempool_alloc(nvme_chap_buf_pool, GFP_KERNEL);
if (!chap->buf) {
chap->error = -ENOMEM;
return;
@@ -1027,3 +1029,27 @@ void nvme_auth_free(struct nvme_ctrl *ctrl)
}
}
EXPORT_SYMBOL_GPL(nvme_auth_free);
+
+int __init nvme_init_auth(void)
+{
+ nvme_chap_buf_cache = kmem_cache_create("nvme-chap-buf-cache",
+ CHAP_BUF_SIZE, 0, SLAB_HWCACHE_ALIGN, NULL);
+ if (!nvme_chap_buf_cache)
+ return -ENOMEM;
+
+ nvme_chap_buf_pool = mempool_create(16, mempool_alloc_slab,
+ mempool_free_slab, nvme_chap_buf_cache);
+ if (!nvme_chap_buf_pool)
+ goto err_destroy_chap_buf_cache;
+
+ return 0;
+err_destroy_chap_buf_cache:
+ kmem_cache_destroy(nvme_chap_buf_cache);
+ return -ENOMEM;
+}
+
+void __exit nvme_exit_auth(void)
+{
+ mempool_destroy(nvme_chap_buf_pool);
+ kmem_cache_destroy(nvme_chap_buf_cache);
+}
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f2ae4ae33d68..b75e8433c3b2 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -5356,8 +5356,13 @@ static int __init nvme_core_init(void)
goto unregister_generic_ns;
}

+ result = nvme_init_auth();
+ if (result)
+ goto destroy_ns_chr;
return 0;

+destroy_ns_chr:
+ class_destroy(nvme_ns_chr_class);
unregister_generic_ns:
unregister_chrdev_region(nvme_ns_chr_devt, NVME_MINORS);
destroy_subsys_class:
@@ -5378,6 +5383,7 @@ static int __init nvme_core_init(void)

static void __exit nvme_core_exit(void)
{
+ nvme_exit_auth();
class_destroy(nvme_ns_chr_class);
class_destroy(nvme_subsys_class);
class_destroy(nvme_class);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index cc314f45ddee..e8eff9edf7f5 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -1019,6 +1019,8 @@ static inline bool nvme_ctrl_sgl_supported(struct nvme_ctrl *ctrl)
}

#ifdef CONFIG_NVME_AUTH
+int __init nvme_init_auth(void);
+void __exit nvme_exit_auth(void);
int nvme_auth_init_ctrl(struct nvme_ctrl *ctrl);
void nvme_auth_stop(struct nvme_ctrl *ctrl);
int nvme_auth_negotiate(struct nvme_ctrl *ctrl, int qid);
@@ -1026,6 +1028,11 @@ int nvme_auth_wait(struct nvme_ctrl *ctrl, int qid);
void nvme_auth_reset(struct nvme_ctrl *ctrl);
void nvme_auth_free(struct nvme_ctrl *ctrl);
#else
+int __init nvme_init_auth(void)
+{
+ return 0;
+}
+void __exit nvme_exit_auth(void) {};
static inline void nvme_auth_init_ctrl(struct nvme_ctrl *ctrl) {};
static inline void nvme_auth_stop(struct nvme_ctrl *ctrl) {};
static inline int nvme_auth_negotiate(struct nvme_ctrl *ctrl, int qid)
--
2.34.1