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	Currently message data items are allocated with ceph_msg_data_create()
in setup_request_data() inside send_request().  send_request() has never
been allowed to fail, so each allocation is followed by a BUG_ON:
  data = ceph_msg_data_create(...);
  BUG_ON(!data);
It's been this way since support for multiple message data items was
added in commit 6644ed7b7e ("libceph: make message data be a pointer")
in 3.10.
There is no reason to delay the allocation of message data items until
the last possible moment and we certainly don't need a linked list of
them as they are only ever appended to the end and never erased.  Make
ceph_msg_new2() take max_data_items and adapt the rest of the code.
Reported-by: Jerry Lee <leisurelysw24@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
		
	
			
		
			
				
	
	
		
			94 lines
		
	
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			94 lines
		
	
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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#include <linux/ceph/ceph_debug.h>
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <linux/types.h>
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#include <linux/vmalloc.h>
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#include <linux/ceph/messenger.h>
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#include <linux/ceph/msgpool.h>
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static void *msgpool_alloc(gfp_t gfp_mask, void *arg)
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{
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	struct ceph_msgpool *pool = arg;
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	struct ceph_msg *msg;
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	msg = ceph_msg_new2(pool->type, pool->front_len, pool->max_data_items,
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			    gfp_mask, true);
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	if (!msg) {
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		dout("msgpool_alloc %s failed\n", pool->name);
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	} else {
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		dout("msgpool_alloc %s %p\n", pool->name, msg);
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		msg->pool = pool;
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	}
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	return msg;
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}
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static void msgpool_free(void *element, void *arg)
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{
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	struct ceph_msgpool *pool = arg;
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	struct ceph_msg *msg = element;
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	dout("msgpool_release %s %p\n", pool->name, msg);
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	msg->pool = NULL;
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	ceph_msg_put(msg);
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}
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int ceph_msgpool_init(struct ceph_msgpool *pool, int type,
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		      int front_len, int max_data_items, int size,
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		      const char *name)
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{
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	dout("msgpool %s init\n", name);
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	pool->type = type;
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	pool->front_len = front_len;
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	pool->max_data_items = max_data_items;
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	pool->pool = mempool_create(size, msgpool_alloc, msgpool_free, pool);
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	if (!pool->pool)
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		return -ENOMEM;
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	pool->name = name;
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	return 0;
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}
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void ceph_msgpool_destroy(struct ceph_msgpool *pool)
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{
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	dout("msgpool %s destroy\n", pool->name);
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	mempool_destroy(pool->pool);
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}
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struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len,
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				  int max_data_items)
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{
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	struct ceph_msg *msg;
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	if (front_len > pool->front_len ||
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	    max_data_items > pool->max_data_items) {
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		pr_warn_ratelimited("%s need %d/%d, pool %s has %d/%d\n",
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		    __func__, front_len, max_data_items, pool->name,
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		    pool->front_len, pool->max_data_items);
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		WARN_ON_ONCE(1);
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		/* try to alloc a fresh message */
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		return ceph_msg_new2(pool->type, front_len, max_data_items,
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				     GFP_NOFS, false);
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	}
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	msg = mempool_alloc(pool->pool, GFP_NOFS);
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	dout("msgpool_get %s %p\n", pool->name, msg);
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	return msg;
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}
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void ceph_msgpool_put(struct ceph_msgpool *pool, struct ceph_msg *msg)
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{
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	dout("msgpool_put %s %p\n", pool->name, msg);
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	/* reset msg front_len; user may have changed it */
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	msg->front.iov_len = pool->front_len;
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	msg->hdr.front_len = cpu_to_le32(pool->front_len);
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	msg->data_length = 0;
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	msg->num_data_items = 0;
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	kref_init(&msg->kref);  /* retake single ref */
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	mempool_free(msg, pool->pool);
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}
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