181011e04a
scsi tgt breaks up a command into multple scatterlists if we cannot fit all the data in one. This was because the block rq helpers did not support large requests and because we can get a command of any old size so it is hard to preallocate pages for scatterlist large enough (we cannot really preallocate pages with the bio map user path). In 2.6.20, we added large request support to the block layer helper, blk_rq_map_user. And at LSF, we talked about increasing SCSI_MAX_PHYS_SEGMENTS for scsi tgt if we want to support really really :) large (greater than 256 * PAGE_SIZE in the worst mapping case) requests. The only target currently implemented does not even support the multiple scatterlists stuff and only supports smaller requests, so this patch just coverts scsi tgt to use blk_rq_map_user. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
138 lines
4.6 KiB
C
138 lines
4.6 KiB
C
#ifndef _SCSI_SCSI_CMND_H
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#define _SCSI_SCSI_CMND_H
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#include <linux/dma-mapping.h>
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#include <linux/list.h>
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#include <linux/types.h>
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#include <linux/timer.h>
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struct request;
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struct scatterlist;
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struct Scsi_Host;
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struct scsi_device;
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/* embedded in scsi_cmnd */
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struct scsi_pointer {
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char *ptr; /* data pointer */
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int this_residual; /* left in this buffer */
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struct scatterlist *buffer; /* which buffer */
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int buffers_residual; /* how many buffers left */
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dma_addr_t dma_handle;
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volatile int Status;
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volatile int Message;
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volatile int have_data_in;
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volatile int sent_command;
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volatile int phase;
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};
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struct scsi_cmnd {
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struct scsi_device *device;
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struct list_head list; /* scsi_cmnd participates in queue lists */
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struct list_head eh_entry; /* entry for the host eh_cmd_q */
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int eh_eflags; /* Used by error handlr */
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void (*done) (struct scsi_cmnd *); /* Mid-level done function */
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/*
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* A SCSI Command is assigned a nonzero serial_number before passed
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* to the driver's queue command function. The serial_number is
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* cleared when scsi_done is entered indicating that the command
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* has been completed. It currently doesn't have much use other
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* than printk's. Some lldd's use this number for other purposes.
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* It's almost certain that such usages are either incorrect or
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* meaningless. Please kill all usages other than printk's. Also,
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* as this number is always identical to ->pid, please convert
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* printk's to use ->pid, so that we can kill this field.
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*/
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unsigned long serial_number;
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/*
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* This is set to jiffies as it was when the command was first
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* allocated. It is used to time how long the command has
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* been outstanding
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*/
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unsigned long jiffies_at_alloc;
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int retries;
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int allowed;
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int timeout_per_command;
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unsigned char cmd_len;
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enum dma_data_direction sc_data_direction;
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/* These elements define the operation we are about to perform */
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#define MAX_COMMAND_SIZE 16
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unsigned char cmnd[MAX_COMMAND_SIZE];
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unsigned request_bufflen; /* Actual request size */
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struct timer_list eh_timeout; /* Used to time out the command. */
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void *request_buffer; /* Actual requested buffer */
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/* These elements define the operation we ultimately want to perform */
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unsigned short use_sg; /* Number of pieces of scatter-gather */
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unsigned short sglist_len; /* size of malloc'd scatter-gather list */
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unsigned underflow; /* Return error if less than
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this amount is transferred */
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unsigned transfersize; /* How much we are guaranteed to
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transfer with each SCSI transfer
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(ie, between disconnect /
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reconnects. Probably == sector
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size */
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int resid; /* Number of bytes requested to be
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transferred less actual number
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transferred (0 if not supported) */
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struct request *request; /* The command we are
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working on */
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#define SCSI_SENSE_BUFFERSIZE 96
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unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE];
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/* obtained by REQUEST SENSE when
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* CHECK CONDITION is received on original
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* command (auto-sense) */
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/* Low-level done function - can be used by low-level driver to point
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* to completion function. Not used by mid/upper level code. */
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void (*scsi_done) (struct scsi_cmnd *);
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/*
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* The following fields can be written to by the host specific code.
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* Everything else should be left alone.
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*/
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struct scsi_pointer SCp; /* Scratchpad used by some host adapters */
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unsigned char *host_scribble; /* The host adapter is allowed to
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* call scsi_malloc and get some memory
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* and hang it here. The host adapter
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* is also expected to call scsi_free
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* to release this memory. (The memory
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* obtained by scsi_malloc is guaranteed
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* to be at an address < 16Mb). */
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int result; /* Status code from lower level driver */
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unsigned char tag; /* SCSI-II queued command tag */
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unsigned long pid; /* Process ID, starts at 0. Unique per host. */
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};
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extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
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extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
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extern void scsi_put_command(struct scsi_cmnd *);
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extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
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struct device *);
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extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
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extern void scsi_finish_command(struct scsi_cmnd *cmd);
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extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
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extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
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size_t *offset, size_t *len);
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extern void scsi_kunmap_atomic_sg(void *virt);
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extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
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extern void scsi_free_sgtable(struct scatterlist *, int);
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#endif /* _SCSI_SCSI_CMND_H */
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