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Commit 44430612 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

rxrpc: abstract away knowledge of IDR internals 

Add idr_get_cursor() / idr_set_cursor() APIs, and remove the reference
to IDR_SIZE.

Link: http://lkml.kernel.org/r/1480369871-5271-65-git-send-email-mawilcox@linuxonhyperv.com


Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 37f4915f

include/linux/idr.h

+26 −0
Original line number Diff line number Diff line
@@ -55,6 +55,32 @@ struct idr { 
}

#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)



/**

 * idr_get_cursor - Return the current position of the cyclic allocator

 * @idr: idr handle

 *

 * The value returned is the value that will be next returned from

 * idr_alloc_cyclic() if it is free (otherwise the search will start from

 * this position).

 */

static inline unsigned int idr_get_cursor(struct idr *idr)

{

	return READ_ONCE(idr->cur);

}



/**

 * idr_set_cursor - Set the current position of the cyclic allocator

 * @idr: idr handle

 * @val: new position

 *

 * The next call to idr_alloc_cyclic() will return @val if it is free

 * (otherwise the search will start from this position).

 */

static inline void idr_set_cursor(struct idr *idr, unsigned int val)

{

	WRITE_ONCE(idr->cur, val);

}



/**

 * DOC: idr sync

 * idr synchronization (stolen from radix-tree.h)

net/rxrpc/af_rxrpc.c

+6 −5
Original line number Diff line number Diff line
@@ -762,16 +762,17 @@ static const struct net_proto_family rxrpc_family_ops = { 
static int __init af_rxrpc_init(void)

{

	int ret = -1;

	unsigned int tmp;



	BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > FIELD_SIZEOF(struct sk_buff, cb));



	get_random_bytes(&rxrpc_epoch, sizeof(rxrpc_epoch));

	rxrpc_epoch |= RXRPC_RANDOM_EPOCH;

	get_random_bytes(&rxrpc_client_conn_ids.cur,

			 sizeof(rxrpc_client_conn_ids.cur));

	rxrpc_client_conn_ids.cur &= 0x3fffffff;

	if (rxrpc_client_conn_ids.cur == 0)

		rxrpc_client_conn_ids.cur = 1;

	get_random_bytes(&tmp, sizeof(tmp));

	tmp &= 0x3fffffff;

	if (tmp == 0)

		tmp = 1;

	idr_set_cursor(&rxrpc_client_conn_ids, tmp);



	ret = -ENOMEM;

	rxrpc_call_jar = kmem_cache_create(

net/rxrpc/conn_client.c

+2 −2
Original line number Diff line number Diff line
@@ -263,12 +263,12 @@ static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn) 
	 * times the maximum number of client conns away from the current

	 * allocation point to try and keep the IDs concentrated.

	 */

	id_cursor = READ_ONCE(rxrpc_client_conn_ids.cur);

	id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);

	id = conn->proto.cid >> RXRPC_CIDSHIFT;

	distance = id - id_cursor;

	if (distance < 0)

		distance = -distance;

	limit = round_up(rxrpc_max_client_connections, IDR_SIZE) * 4;

	limit = max(rxrpc_max_client_connections * 4, 1024U);

	if (distance > limit)

		goto mark_dont_reuse;