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authorStefani Seibold <stefani@seibold.net>2009-12-21 14:37:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-22 14:17:55 -0800
commit45465487897a1c6d508b14b904dc5777f7ec7e04 (patch)
tree935c8dae68dc793ff2f795d57cf027531475cd53 /include/scsi
parent2ec91eec47f713e3d158ba5b28a24a85a2cf3650 (diff)
downloadlinux-linaro-android-45465487897a1c6d508b14b904dc5777f7ec7e04.tar.gz
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>
Diffstat (limited to 'include/scsi')
-rw-r--r--include/scsi/libiscsi.h3
-rw-r--r--include/scsi/libiscsi_tcp.h2
-rw-r--r--include/scsi/libsrp.h2
3 files changed, 4 insertions, 3 deletions
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 7394e3bc8f4..ff92b46f515 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -28,6 +28,7 @@
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
+#include <linux/kfifo.h>
#include <scsi/iscsi_proto.h>
#include <scsi/iscsi_if.h>
#include <scsi/scsi_transport_iscsi.h>
@@ -231,7 +232,7 @@ struct iscsi_conn {
};
struct iscsi_pool {
- struct kfifo *queue; /* FIFO Queue */
+ struct kfifo queue; /* FIFO Queue */
void **pool; /* Pool of elements */
int max; /* Max number of elements */
};
diff --git a/include/scsi/libiscsi_tcp.h b/include/scsi/libiscsi_tcp.h
index 9e3182e659d..741ae7ed439 100644
--- a/include/scsi/libiscsi_tcp.h
+++ b/include/scsi/libiscsi_tcp.h
@@ -80,7 +80,7 @@ struct iscsi_tcp_task {
int data_offset;
struct iscsi_r2t_info *r2t; /* in progress solict R2T */
struct iscsi_pool r2tpool;
- struct kfifo *r2tqueue;
+ struct kfifo r2tqueue;
void *dd_data;
};
diff --git a/include/scsi/libsrp.h b/include/scsi/libsrp.h
index ba615e4c1d7..07e3adde21d 100644
--- a/include/scsi/libsrp.h
+++ b/include/scsi/libsrp.h
@@ -21,7 +21,7 @@ struct srp_buf {
struct srp_queue {
void *pool;
void *items;
- struct kfifo *queue;
+ struct kfifo queue;
spinlock_t lock;
};