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6f9a35e2da
At the block level bidi request uses req->next_rq pointer for a second bidi_read request. At Scsi-midlayer a second scsi_data_buffer structure is used for the bidi_read part. This bidi scsi_data_buffer is put on request->next_rq->special. Struct scsi_cmnd is not changed. - Define scsi_bidi_cmnd() to return true if it is a bidi request and a second sgtable was allocated. - Define scsi_in()/scsi_out() to return the in or out scsi_data_buffer from this command This API is to isolate users from the mechanics of bidi. - Define scsi_end_bidi_request() to do what scsi_end_request() does but for a bidi request. This is necessary because bidi commands are a bit tricky here. (See comments in body) - scsi_release_buffers() will also release the bidi_read scsi_data_buffer - scsi_io_completion() on bidi commands will now call scsi_end_bidi_request() and return. - The previous work done in scsi_init_io() is now done in a new scsi_init_sgtable() (which is 99% identical to old scsi_init_io()) The new scsi_init_io() will call the above twice if needed also for the bidi_read command. Only at this point is a command bidi. - In scsi_error.c at scsi_eh_prep/restore_cmnd() make sure bidi-lld is not confused by a get-sense command that looks like bidi. This is done by puting NULL at request->next_rq, and restoring. [jejb: update to sg_table and resolve conflicts also update to blk-end-request and resolve conflicts] Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
179 lines
5.0 KiB
C
179 lines
5.0 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/blkdev.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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#include <linux/scatterlist.h>
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struct Scsi_Host;
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struct scsi_device;
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struct scsi_data_buffer {
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struct sg_table table;
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unsigned length;
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int resid;
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};
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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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/*
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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 is a bug for LLDDs to use this number
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* for purposes other than printk (and even that is only useful
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* for debugging).
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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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struct timer_list eh_timeout; /* Used to time out the command. */
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/* These elements define the operation we ultimately want to perform */
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struct scsi_data_buffer sdb;
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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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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;
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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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};
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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_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 int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
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extern void scsi_release_buffers(struct scsi_cmnd *cmd);
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extern int scsi_dma_map(struct scsi_cmnd *cmd);
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extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
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static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
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{
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return cmd->sdb.table.nents;
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}
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static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
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{
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return cmd->sdb.table.sgl;
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}
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static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
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{
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return cmd->sdb.length;
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}
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static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
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{
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cmd->sdb.resid = resid;
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}
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static inline int scsi_get_resid(struct scsi_cmnd *cmd)
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{
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return cmd->sdb.resid;
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}
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#define scsi_for_each_sg(cmd, sg, nseg, __i) \
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for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
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static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
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{
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return blk_bidi_rq(cmd->request) &&
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(cmd->request->next_rq->special != NULL);
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}
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static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
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{
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return scsi_bidi_cmnd(cmd) ?
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cmd->request->next_rq->special : &cmd->sdb;
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}
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static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
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{
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return &cmd->sdb;
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}
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#endif /* _SCSI_SCSI_CMND_H */
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