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/usb/host/fhci-sched.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/usb/host/fhci-sched.c') diff --git a/drivers/usb/host/fhci-sched.c b/drivers/usb/host/fhci-sched.c index 00a29855d0c4..ff43747a614f 100644 --- a/drivers/usb/host/fhci-sched.c +++ b/drivers/usb/host/fhci-sched.c @@ -37,7 +37,7 @@ static void recycle_frame(struct fhci_usb *usb, struct packet *pkt) pkt->info = 0; pkt->priv_data = NULL; - cq_put(usb->ep0->empty_frame_Q, pkt); + cq_put(&usb->ep0->empty_frame_Q, pkt); } /* confirm submitted packet */ @@ -57,7 +57,7 @@ void fhci_transaction_confirm(struct fhci_usb *usb, struct packet *pkt) if ((td->data + td->actual_len) && trans_len) memcpy(td->data + td->actual_len, pkt->data, trans_len); - cq_put(usb->ep0->dummy_packets_Q, pkt->data); + cq_put(&usb->ep0->dummy_packets_Q, pkt->data); } recycle_frame(usb, pkt); @@ -213,7 +213,7 @@ static int add_packet(struct fhci_usb *usb, struct ed *ed, struct td *td) } /* update frame object fields before transmitting */ - pkt = cq_get(usb->ep0->empty_frame_Q); + pkt = cq_get(&usb->ep0->empty_frame_Q); if (!pkt) { fhci_dbg(usb->fhci, "there is no empty frame\n"); return -1; @@ -222,7 +222,7 @@ static int add_packet(struct fhci_usb *usb, struct ed *ed, struct td *td) pkt->info = 0; if (data == NULL) { - data = cq_get(usb->ep0->dummy_packets_Q); + data = cq_get(&usb->ep0->dummy_packets_Q); BUG_ON(!data); pkt->info = PKT_DUMMY_PACKET; } @@ -246,7 +246,7 @@ static int add_packet(struct fhci_usb *usb, struct ed *ed, struct td *td) list_del_init(&td->frame_lh); td->status = USB_TD_OK; if (pkt->info & PKT_DUMMY_PACKET) - cq_put(usb->ep0->dummy_packets_Q, pkt->data); + cq_put(&usb->ep0->dummy_packets_Q, pkt->data); recycle_frame(usb, pkt); usb->actual_frame->total_bytes -= (len + PROTOCOL_OVERHEAD); fhci_err(usb->fhci, "host transaction failed\n"); -- cgit v1.2.3