b21a413851
There are certain rogue devices (and the aic7xxx driver) that return BUSY or QUEUE_FULL forever. This code will apply a global timeout (of the total number of retries times the per command timer) to a given command. If it is exceeded, the command is completed regardless of its state. The patch also removes the unused field in the command: timeout and timeout_total. This solves the problem of detecting an endless loop in the mid-layer because of BUSY/QUEUE_FULL bouncing, but will not recover the device. In the aic7xxx case, the driver can be recovered by sending a bus reset, so possibly this should be tied into the error handler? Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
155 lines
5.0 KiB
C
155 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/list.h>
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#include <linux/types.h>
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struct request;
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struct scatterlist;
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struct scsi_device;
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struct scsi_request;
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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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int sc_magic;
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struct scsi_device *device;
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struct scsi_request *sc_request;
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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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unsigned char old_cmd_len;
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enum dma_data_direction sc_data_direction;
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enum dma_data_direction sc_old_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 char data_cmnd[MAX_COMMAND_SIZE];
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unsigned short old_use_sg; /* We save use_sg here when requesting
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* sense info */
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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 bufflen; /* Size of data buffer */
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void *buffer; /* Data buffer */
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unsigned underflow; /* Return error if less than
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this amount is transferred */
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unsigned old_underflow; /* save underflow here when reusing the
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* command for error handling */
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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]; /* obtained by REQUEST SENSE
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* when CHECK CONDITION is
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* received on original command
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* (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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/*
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* These are the values that scsi_cmd->state can take.
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*/
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#define SCSI_STATE_TIMEOUT 0x1000
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#define SCSI_STATE_FINISHED 0x1001
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#define SCSI_STATE_FAILED 0x1002
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#define SCSI_STATE_QUEUED 0x1003
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#define SCSI_STATE_UNUSED 0x1006
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#define SCSI_STATE_DISCONNECTING 0x1008
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#define SCSI_STATE_INITIALIZING 0x1009
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#define SCSI_STATE_BHQUEUE 0x100a
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#define SCSI_STATE_MLQUEUE 0x100b
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extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, int);
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extern void scsi_put_command(struct scsi_cmnd *);
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extern void scsi_io_completion(struct scsi_cmnd *, unsigned int, unsigned int);
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extern void scsi_finish_command(struct scsi_cmnd *cmd);
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#endif /* _SCSI_SCSI_CMND_H */
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