From 45465487897a1c6d508b14b904dc5777f7ec7e04 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:26 -0800 Subject: kfifo: move struct kfifo in place This is a new generic kernel FIFO implementation. The current kernel fifo API is not very widely used, because it has to many constrains. Only 17 files in the current 2.6.31-rc5 used it. FIFO's are like list's a very basic thing and a kfifo API which handles the most use case would save a lot of development time and memory resources. I think this are the reasons why kfifo is not in use: - The API is to simple, important functions are missing - A fifo can be only allocated dynamically - There is a requirement of a spinlock whether you need it or not - There is no support for data records inside a fifo So I decided to extend the kfifo in a more generic way without blowing up the API to much. The new API has the following benefits: - Generic usage: For kernel internal use and/or device driver. - Provide an API for the most use case. - Slim API: The whole API provides 25 functions. - Linux style habit. - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros - Direct copy_to_user from the fifo and copy_from_user into the fifo. - The kfifo itself is an in place member of the using data structure, this save an indirection access and does not waste the kernel allocator. - Lockless access: if only one reader and one writer is active on the fifo, which is the common use case, no additional locking is necessary. - Remove spinlock - give the user the freedom of choice what kind of locking to use if one is required. - Ability to handle records. Three type of records are supported: - Variable length records between 0-255 bytes, with a record size field of 1 bytes. - Variable length records between 0-65535 bytes, with a record size field of 2 bytes. - Fixed size records, which no record size field. - Preserve memory resource. - Performance! - Easy to use! This patch: Since most users want to have the kfifo as part of another object, reorganize the code to allow including struct kfifo in another data structure. This requires changing the kfifo_alloc and kfifo_init prototypes so that we pass an existing kfifo pointer into them. This patch changes the implementation and all existing users. [akpm@linux-foundation.org: fix warning] Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/scsi/libiscsi_tcp.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) (limited to 'drivers/scsi/libiscsi_tcp.c') diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c index ca25ee5190b0..a83ee56a185e 100644 --- a/drivers/scsi/libiscsi_tcp.c +++ b/drivers/scsi/libiscsi_tcp.c @@ -445,15 +445,15 @@ void iscsi_tcp_cleanup_task(struct iscsi_task *task) return; /* flush task's r2t queues */ - while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) { - __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + while (__kfifo_get(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) { + __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n"); } r2t = tcp_task->r2t; if (r2t != NULL) { - __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); tcp_task->r2t = NULL; } @@ -541,7 +541,7 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) return 0; } - rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); + rc = __kfifo_get(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); if (!rc) { iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. " "Target has sent more R2Ts than it " @@ -554,7 +554,7 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) if (r2t->data_length == 0) { iscsi_conn_printk(KERN_ERR, conn, "invalid R2T with zero data len\n"); - __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); return ISCSI_ERR_DATALEN; } @@ -570,7 +570,7 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) "invalid R2T with data len %u at offset %u " "and total length %d\n", r2t->data_length, r2t->data_offset, scsi_out(task->sc)->length); - __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); return ISCSI_ERR_DATALEN; } @@ -580,7 +580,7 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) r2t->sent = 0; tcp_task->exp_datasn = r2tsn + 1; - __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*)); + __kfifo_put(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*)); conn->r2t_pdus_cnt++; iscsi_requeue_task(task); @@ -951,7 +951,7 @@ int iscsi_tcp_task_init(struct iscsi_task *task) return conn->session->tt->init_pdu(task, 0, task->data_count); } - BUG_ON(__kfifo_len(tcp_task->r2tqueue)); + BUG_ON(__kfifo_len(&tcp_task->r2tqueue)); tcp_task->exp_datasn = 0; /* Prepare PDU, optionally w/ immediate data */ @@ -982,7 +982,7 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task) if (r2t->data_length <= r2t->sent) { ISCSI_DBG_TCP(task->conn, " done with r2t %p\n", r2t); - __kfifo_put(tcp_task->r2tpool.queue, + __kfifo_put(&tcp_task->r2tpool.queue, (void *)&tcp_task->r2t, sizeof(void *)); tcp_task->r2t = r2t = NULL; @@ -990,7 +990,7 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task) } if (r2t == NULL) { - __kfifo_get(tcp_task->r2tqueue, + __kfifo_get(&tcp_task->r2tqueue, (void *)&tcp_task->r2t, sizeof(void *)); r2t = tcp_task->r2t; } @@ -1127,9 +1127,8 @@ int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session) } /* R2T xmit queue */ - tcp_task->r2tqueue = kfifo_alloc( - session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL); - if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) { + if (kfifo_alloc(&tcp_task->r2tqueue, + session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL)) { iscsi_pool_free(&tcp_task->r2tpool); goto r2t_alloc_fail; } @@ -1142,7 +1141,7 @@ r2t_alloc_fail: struct iscsi_task *task = session->cmds[i]; struct iscsi_tcp_task *tcp_task = task->dd_data; - kfifo_free(tcp_task->r2tqueue); + kfifo_free(&tcp_task->r2tqueue); iscsi_pool_free(&tcp_task->r2tpool); } return -ENOMEM; @@ -1157,7 +1156,7 @@ void iscsi_tcp_r2tpool_free(struct iscsi_session *session) struct iscsi_task *task = session->cmds[i]; struct iscsi_tcp_task *tcp_task = task->dd_data; - kfifo_free(tcp_task->r2tqueue); + kfifo_free(&tcp_task->r2tqueue); iscsi_pool_free(&tcp_task->r2tpool); } } -- cgit