Commit 4d784c04 authored by Bart Van Assche's avatar Bart Van Assche Committed by Jason Gunthorpe
Browse files

RDMA/srpt: Make slab cache names unique 

Since commit 4c395296 ("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().

Fixes: 5dabcd04 ("RDMA/srpt: Add support for immediate data")
Link: https://patch.msgid.link/r/20241009210048.4122518-1-bvanassche@acm.org


Reported-by: default avatarShinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Closes: https://lore.kernel.org/linux-block/xpe6bea7rakpyoyfvspvin2dsozjmjtjktpph7rep3h25tv7fb@ooz4cu5z6bq6/


Suggested-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Tested-by: default avatarShin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 8cddfa53

drivers/infiniband/ulp/srpt/ib_srpt.c

+68 −12
Original line number Diff line number Diff line
@@ -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 +107,63 @@ 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];

	void *res;



	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;

	res = xa_store(&srpt_memory_caches, object_size, e, GFP_KERNEL);

	if (xa_is_err(res))

		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;

	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 +2178,13 @@ 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 +2304,7 @@ 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 +2338,7 @@ 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 +2535,7 @@ 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 +2543,7 @@ 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 +3112,7 @@ 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 +3139,7 @@ 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 +3161,7 @@ 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);