Since commit 4c39529663b9 ("slab: Warn on duplicate cache names when
DEBUG_VM=y"), slab complains about duplicate cache names. Hence this
patch. The approach is as follows:
- Maintain an xarray with the slab size as index and a reference count
and a kmem_cache pointer as contents. Use srpt-${slab_size} as kmem
cache name.
- Use 512-byte alignment for all slabs instead of only for some of the
slabs.
- Increment the reference count instead of calling kmem_cache_create().
- Decrement the reference count instead of calling kmem_cache_destroy().
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
Closes: https://lore.kernel.org/linux-block/xpe6bea7rakpyoyfvspvin2dsozjmjtjktpph7rep3h25tv7fb@ooz4cu5z6bq6/
Cc: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>
Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Fixes: 5dabcd0456d7 ("RDMA/srpt: Add support for immediate data")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/infiniband/ulp/srpt/ib_srpt.c | 79 +++++++++++++++++++++++----
1 file changed, 67 insertions(+), 12 deletions(-)
Changes compared to v1:
- Instead of using an ida to make slab names unique, maintain an xarray
with the slab size as index and the slab pointer and a reference count as
contents.
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 9632afbd727b..cc18179693bf 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -68,6 +68,8 @@ MODULE_LICENSE("Dual BSD/GPL");
static u64 srpt_service_guid;
static DEFINE_SPINLOCK(srpt_dev_lock); /* Protects srpt_dev_list. */
static LIST_HEAD(srpt_dev_list); /* List of srpt_device structures. */
+static DEFINE_MUTEX(srpt_mc_mutex); /* Protects srpt_memory_caches. */
+static DEFINE_XARRAY(srpt_memory_caches); /* See also srpt_memory_cache_entry */
static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
module_param(srp_max_req_size, int, 0444);
@@ -105,6 +107,62 @@ static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
+/* Type of the entries in srpt_memory_caches. */
+struct srpt_memory_cache_entry {
+ refcount_t ref;
+ struct kmem_cache *c;
+};
+
+static struct kmem_cache *srpt_cache_get(unsigned int object_size)
+{
+ struct srpt_memory_cache_entry *e;
+ char name[32];
+
+ guard(mutex)(&srpt_mc_mutex);
+ e = xa_load(&srpt_memory_caches, object_size);
+ if (e) {
+ refcount_inc(&e->ref);
+ return e->c;
+ }
+ snprintf(name, sizeof(name), "srpt-%u", object_size);
+ e = kmalloc(sizeof(*e), GFP_KERNEL);
+ if (!e)
+ return NULL;
+ refcount_set(&e->ref, 1);
+ e->c = kmem_cache_create(name, object_size, /*align=*/512, 0, NULL);
+ if (!e->c)
+ goto free_entry;
+ if (IS_ERR(xa_store(&srpt_memory_caches, object_size, e, GFP_KERNEL)))
+ goto destroy_cache;
+ return e->c;
+
+destroy_cache:
+ kmem_cache_destroy(e->c);
+
+free_entry:
+ kfree(e);
+ return NULL;
+}
+
+static void srpt_cache_put(struct kmem_cache *c)
+{
+ struct srpt_memory_cache_entry *e = NULL;
+ unsigned long object_size;
+
+ guard(mutex)(&srpt_mc_mutex);
+ xa_for_each(&srpt_memory_caches, object_size, e)
+ if (e->c == c)
+ break;
+ if (WARN_ON_ONCE(!e))
+ return;
+ WARN_ON_ONCE(e->c != c);
+ if (!refcount_dec_and_test(&e->ref))
+ return;
+ WARN_ON_ONCE(xa_erase(&srpt_memory_caches, object_size) != e);
+ kmem_cache_destroy(e->c);
+ kfree(e);
+}
+
/*
* The only allowed channel state changes are those that change the channel
* state into a state with a higher numerical value. Hence the new > prev test.
@@ -2119,13 +2177,13 @@ static void srpt_release_channel_work(struct work_struct *w)
ch->sport->sdev, ch->rq_size,
ch->rsp_buf_cache, DMA_TO_DEVICE);
- kmem_cache_destroy(ch->rsp_buf_cache);
+ srpt_cache_put(ch->rsp_buf_cache);
srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
sdev, ch->rq_size,
ch->req_buf_cache, DMA_FROM_DEVICE);
- kmem_cache_destroy(ch->req_buf_cache);
+ srpt_cache_put(ch->req_buf_cache);
kref_put(&ch->kref, srpt_free_ch);
}
@@ -2245,8 +2303,7 @@ static int srpt_cm_req_recv(struct srpt_device *const sdev,
INIT_LIST_HEAD(&ch->cmd_wait_list);
ch->max_rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
- ch->rsp_buf_cache = kmem_cache_create("srpt-rsp-buf", ch->max_rsp_size,
- 512, 0, NULL);
+ ch->rsp_buf_cache = srpt_cache_get(ch->max_rsp_size);
if (!ch->rsp_buf_cache)
goto free_ch;
@@ -2280,8 +2337,7 @@ static int srpt_cm_req_recv(struct srpt_device *const sdev,
alignment_offset = round_up(imm_data_offset, 512) -
imm_data_offset;
req_sz = alignment_offset + imm_data_offset + srp_max_req_size;
- ch->req_buf_cache = kmem_cache_create("srpt-req-buf", req_sz,
- 512, 0, NULL);
+ ch->req_buf_cache = srpt_cache_get(req_sz);
if (!ch->req_buf_cache)
goto free_rsp_ring;
@@ -2478,7 +2534,7 @@ static int srpt_cm_req_recv(struct srpt_device *const sdev,
ch->req_buf_cache, DMA_FROM_DEVICE);
free_recv_cache:
- kmem_cache_destroy(ch->req_buf_cache);
+ srpt_cache_put(ch->req_buf_cache);
free_rsp_ring:
srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
@@ -2486,7 +2542,7 @@ static int srpt_cm_req_recv(struct srpt_device *const sdev,
ch->rsp_buf_cache, DMA_TO_DEVICE);
free_rsp_cache:
- kmem_cache_destroy(ch->rsp_buf_cache);
+ srpt_cache_put(ch->rsp_buf_cache);
free_ch:
if (rdma_cm_id)
@@ -3055,7 +3111,7 @@ static void srpt_free_srq(struct srpt_device *sdev)
srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
sdev->srq_size, sdev->req_buf_cache,
DMA_FROM_DEVICE);
- kmem_cache_destroy(sdev->req_buf_cache);
+ srpt_cache_put(sdev->req_buf_cache);
sdev->srq = NULL;
}
@@ -3082,8 +3138,7 @@ static int srpt_alloc_srq(struct srpt_device *sdev)
pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n", sdev->srq_size,
sdev->device->attrs.max_srq_wr, dev_name(&device->dev));
- sdev->req_buf_cache = kmem_cache_create("srpt-srq-req-buf",
- srp_max_req_size, 0, 0, NULL);
+ sdev->req_buf_cache = srpt_cache_get(srp_max_req_size);
if (!sdev->req_buf_cache)
goto free_srq;
@@ -3105,7 +3160,7 @@ static int srpt_alloc_srq(struct srpt_device *sdev)
return 0;
free_cache:
- kmem_cache_destroy(sdev->req_buf_cache);
+ srpt_cache_put(sdev->req_buf_cache);
free_srq:
ib_destroy_srq(srq);
