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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 27 insertions, 28 deletions

diff --git a/drivers/usb/host/fhci-sched.c b/drivers/usb/host/fhci-sched.c
index 00a29855d0c..ff43747a614 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");
diff --git a/drivers/usb/host/fhci-tds.c b/drivers/usb/host/fhci-tds.c
index b4033229031..d224ab467a4 100644
--- a/drivers/usb/host/fhci-tds.c
+++ b/drivers/usb/host/fhci-tds.c
@@ -106,33 +106,33 @@ void fhci_ep0_free(struct fhci_usb *usb)
 			cpm_muram_free(cpm_muram_offset(ep->td_base));
 
 		if (ep->conf_frame_Q) {
-			size = cq_howmany(ep->conf_frame_Q);
+			size = cq_howmany(&ep->conf_frame_Q);
 			for (; size; size--) {
-				struct packet *pkt = cq_get(ep->conf_frame_Q);
+				struct packet *pkt = cq_get(&ep->conf_frame_Q);
 
 				kfree(pkt);
 			}
-			cq_delete(ep->conf_frame_Q);
+			cq_delete(&ep->conf_frame_Q);
 		}
 
 		if (ep->empty_frame_Q) {
-			size = cq_howmany(ep->empty_frame_Q);
+			size = cq_howmany(&ep->empty_frame_Q);
 			for (; size; size--) {
-				struct packet *pkt = cq_get(ep->empty_frame_Q);
+				struct packet *pkt = cq_get(&ep->empty_frame_Q);
 
 				kfree(pkt);
 			}
-			cq_delete(ep->empty_frame_Q);
+			cq_delete(&ep->empty_frame_Q);
 		}
 
 		if (ep->dummy_packets_Q) {
-			size = cq_howmany(ep->dummy_packets_Q);
+			size = cq_howmany(&ep->dummy_packets_Q);
 			for (; size; size--) {
-				u8 *buff = cq_get(ep->dummy_packets_Q);
+				u8 *buff = cq_get(&ep->dummy_packets_Q);
 
 				kfree(buff);
 			}
-			cq_delete(ep->dummy_packets_Q);
+			cq_delete(&ep->dummy_packets_Q);
 		}
 
 		kfree(ep);
@@ -175,10 +175,9 @@ u32 fhci_create_ep(struct fhci_usb *usb, enum fhci_mem_alloc data_mem,
 	ep->td_base = cpm_muram_addr(ep_offset);
 
 	/* zero all queue pointers */
-	ep->conf_frame_Q = cq_new(ring_len + 2);
-	ep->empty_frame_Q = cq_new(ring_len + 2);
-	ep->dummy_packets_Q = cq_new(ring_len + 2);
-	if (!ep->conf_frame_Q || !ep->empty_frame_Q || !ep->dummy_packets_Q) {
+	if (cq_new(&ep->conf_frame_Q, ring_len + 2) ||
+	    cq_new(&ep->empty_frame_Q, ring_len + 2) ||
+	    cq_new(&ep->dummy_packets_Q, ring_len + 2)) {
 		err_for = "frame_queues";
 		goto err;
 	}
@@ -199,8 +198,8 @@ u32 fhci_create_ep(struct fhci_usb *usb, enum fhci_mem_alloc data_mem,
 			err_for = "buffer";
 			goto err;
 		}
-		cq_put(ep->empty_frame_Q, pkt);
-		cq_put(ep->dummy_packets_Q, buff);
+		cq_put(&ep->empty_frame_Q, pkt);
+		cq_put(&ep->dummy_packets_Q, buff);
 	}
 
 	/* we put the endpoint parameter RAM right behind the TD ring */
@@ -319,7 +318,7 @@ static void fhci_td_transaction_confirm(struct fhci_usb *usb)
 		if ((buf == DUMMY2_BD_BUFFER) && !(td_status & ~TD_W))
 			continue;
 
-		pkt = cq_get(ep->conf_frame_Q);
+		pkt = cq_get(&ep->conf_frame_Q);
 		if (!pkt)
 			fhci_err(usb->fhci, "no frame to confirm\n");
 
@@ -460,9 +459,9 @@ u32 fhci_host_transaction(struct fhci_usb *usb,
 		out_be16(&td->length, pkt->len);
 
 	/* put the frame to the confirmation queue */
-	cq_put(ep->conf_frame_Q, pkt);
+	cq_put(&ep->conf_frame_Q, pkt);
 
-	if (cq_howmany(ep->conf_frame_Q) == 1)
+	if (cq_howmany(&ep->conf_frame_Q) == 1)
 		out_8(&usb->fhci->regs->usb_comm, USB_CMD_STR_FIFO);
 
 	return 0;
diff --git a/drivers/usb/host/fhci.h b/drivers/usb/host/fhci.h
index 7116284ed21..2277428ef5d 100644
--- a/drivers/usb/host/fhci.h
+++ b/drivers/usb/host/fhci.h
@@ -423,9 +423,9 @@ struct endpoint {
 	struct usb_td __iomem *td_base; /* first TD in the ring */
 	struct usb_td __iomem *conf_td; /* next TD for confirm after transac */
 	struct usb_td __iomem *empty_td;/* next TD for new transaction req. */
-	struct kfifo *empty_frame_Q;  /* Empty frames list to use */
-	struct kfifo *conf_frame_Q;   /* frames passed to TDs,waiting for tx */
-	struct kfifo *dummy_packets_Q;/* dummy packets for the CRC overun */
+	struct kfifo empty_frame_Q;  /* Empty frames list to use */
+	struct kfifo conf_frame_Q;   /* frames passed to TDs,waiting for tx */
+	struct kfifo dummy_packets_Q;/* dummy packets for the CRC overun */
 
 	bool already_pushed_dummy_bd;
 };
@@ -493,9 +493,9 @@ static inline struct usb_hcd *fhci_to_hcd(struct fhci_hcd *fhci)
 }
 
 /* fifo of pointers */
-static inline struct kfifo *cq_new(int size)
+static inline int cq_new(struct kfifo *fifo, int size)
 {
-	return kfifo_alloc(size * sizeof(void *), GFP_KERNEL, NULL);
+	return kfifo_alloc(fifo, size * sizeof(void *), GFP_KERNEL, NULL);
 }
 
 static inline void cq_delete(struct kfifo *kfifo)