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linux-next/include/scsi/libsrp.h

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#ifndef __LIBSRP_H__
#define __LIBSRP_H__
#include <linux/list.h>
#include <linux/kfifo.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <scsi/srp.h>
enum iue_flags {
V_DIOVER,
V_WRITE,
V_LINKED,
V_FLYING,
};
struct srp_buf {
dma_addr_t dma;
void *buf;
};
struct srp_queue {
void *pool;
void *items;
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>
2009-12-22 06:37:26 +08:00
struct kfifo queue;
spinlock_t lock;
};
struct srp_target {
struct Scsi_Host *shost;
struct device *dev;
spinlock_t lock;
struct list_head cmd_queue;
size_t srp_iu_size;
struct srp_queue iu_queue;
size_t rx_ring_size;
struct srp_buf **rx_ring;
void *ldata;
};
struct iu_entry {
struct srp_target *target;
struct list_head ilist;
dma_addr_t remote_token;
unsigned long flags;
struct srp_buf *sbuf;
};
typedef int (srp_rdma_t)(struct scsi_cmnd *, struct scatterlist *, int,
struct srp_direct_buf *, int,
enum dma_data_direction, unsigned int);
extern int srp_target_alloc(struct srp_target *, struct device *, size_t, size_t);
extern void srp_target_free(struct srp_target *);
extern struct iu_entry *srp_iu_get(struct srp_target *);
extern void srp_iu_put(struct iu_entry *);
extern int srp_cmd_queue(struct Scsi_Host *, struct srp_cmd *, void *, u64, u64);
extern int srp_transfer_data(struct scsi_cmnd *, struct srp_cmd *,
srp_rdma_t, int, int);
static inline struct srp_target *host_to_srp_target(struct Scsi_Host *host)
{
return (struct srp_target *) host->hostdata;
}
static inline int srp_cmd_direction(struct srp_cmd *cmd)
{
return (cmd->buf_fmt >> 4) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
}
#endif