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Commit e1c23468 authored by Boaz Harrosh's avatar Boaz Harrosh Committed by James Bottomley
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[SCSI] scsi_error: Refactoring scsi_error to facilitate in synchronous REQUEST_SENSE 



 - Drivers/transports that want to send a synchronous REQUEST_SENSE command
   as part of their .queuecommand sequence, have 2 new API's that facilitate
   in doing so and abstract them from scsi-ml internals.

   void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd,
	struct scsi_eh_save *sesci, unsigned char *cmnd,
	int cmnd_size, int sense_bytes)

   Will hijack a command and prepare it for request sense if needed.
   And will save any later needed info into a scsi_eh_save structure.

   void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd,
	struct scsi_eh_save *sesci);

   Will undo any changes done to a command by above function. Making
   it ready for completion.

 - Re-factor scsi_send_eh_cmnd() to use above APIs

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 55db6c1b

drivers/scsi/scsi_error.c

+68 −46
Original line number Diff line number Diff line
@@ -590,42 +590,23 @@ static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd) 
}



/**

 * scsi_send_eh_cmnd  - submit a scsi command as part of error recory

 * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory

 * @scmd:       SCSI command structure to hijack

 * @ses:        structure to save restore information

 * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed

 * @cmnd_size:  size in bytes of @cmnd

 * @timeout:    timeout for this request

 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)

 *

 * This function is used to send a scsi command down to a target device

 * This function is used to save a scsi command information before re-execution

 * as part of the error recovery process.  If @sense_bytes is 0 the command

 * sent must be one that does not transfer any data.  If @sense_bytes != 0

 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command

 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.

 *

 * Return value:

 *    SUCCESS or FAILED or NEEDS_RETRY

 **/

static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,

			     int cmnd_size, int timeout, unsigned sense_bytes)

void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,

			unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)

{

	struct scsi_device *sdev = scmd->device;

	struct Scsi_Host *shost = sdev->host;

	DECLARE_COMPLETION_ONSTACK(done);

	unsigned long timeleft;

	unsigned long flags;



	unsigned char old_cmd_len;

	unsigned char old_cmnd[MAX_COMMAND_SIZE];

	enum dma_data_direction old_data_direction;

	unsigned old_bufflen;

	void *old_buffer;

	unsigned short old_use_sg;

	int old_resid;

	int old_result;



	struct scatterlist sgl;

	int rtn;



	/*

	 * We need saved copies of a number of fields - this is because
@@ -634,20 +615,21 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, 
	 * we will need to restore these values prior to running the actual

	 * command.

	 */

	old_cmd_len = scmd->cmd_len;

	memcpy(old_cmnd, scmd->cmnd, sizeof(scmd->cmnd));

	old_data_direction = scmd->sc_data_direction;

	old_bufflen = scmd->request_bufflen;

	old_buffer = scmd->request_buffer;

	old_use_sg = scmd->use_sg;

	old_resid = scmd->resid;

	old_result = scmd->result;

	ses->cmd_len = scmd->cmd_len;

	memcpy(ses->cmnd, scmd->cmnd, sizeof(scmd->cmnd));

	ses->data_direction = scmd->sc_data_direction;

	ses->bufflen = scmd->request_bufflen;

	ses->buffer = scmd->request_buffer;

	ses->use_sg = scmd->use_sg;

	ses->resid = scmd->resid;

	ses->result = scmd->result;



	if (sense_bytes) {

		scmd->request_bufflen = min_t(unsigned,

		                       sizeof(scmd->sense_buffer), sense_bytes);

		sg_init_one(&sgl, scmd->sense_buffer, scmd->request_bufflen);

		scmd->request_buffer = &sgl;

		sg_init_one(&ses->sense_sgl, scmd->sense_buffer,

		                                       scmd->request_bufflen);

		scmd->request_buffer = &ses->sense_sgl;

		scmd->sc_data_direction = DMA_FROM_DEVICE;

		scmd->use_sg = 1;

		memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
@@ -677,7 +659,58 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, 
	 * untransferred sense data should be interpreted as being zero.

	 */

	memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));

}

EXPORT_SYMBOL(scsi_eh_prep_cmnd);



/**

 * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory

 * @scmd:       SCSI command structure to restore

 * @ses:        saved information from a coresponding call to scsi_prep_eh_cmnd

 *

 * Undo any damage done by above scsi_prep_eh_cmnd().

 **/

void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)

{

	/*

	 * Restore original data

	 */

	scmd->cmd_len = ses->cmd_len;

	memcpy(scmd->cmnd, ses->cmnd, sizeof(scmd->cmnd));

	scmd->sc_data_direction = ses->data_direction;

	scmd->request_bufflen = ses->bufflen;

	scmd->request_buffer = ses->buffer;

	scmd->use_sg = ses->use_sg;

	scmd->resid = ses->resid;

	scmd->result = ses->result;

}

EXPORT_SYMBOL(scsi_eh_restore_cmnd);



/**

 * scsi_send_eh_cmnd  - submit a scsi command as part of error recory

 * @scmd:       SCSI command structure to hijack

 * @cmnd:       CDB to send

 * @cmnd_size:  size in bytes of @cmnd

 * @timeout:    timeout for this request

 * @sense_bytes: size of sense data to copy or 0

 *

 * This function is used to send a scsi command down to a target device

 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.

 *

 * Return value:

 *    SUCCESS or FAILED or NEEDS_RETRY

 **/

static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,

			     int cmnd_size, int timeout, unsigned sense_bytes)

{

	struct scsi_device *sdev = scmd->device;

	struct Scsi_Host *shost = sdev->host;

	DECLARE_COMPLETION_ONSTACK(done);

	unsigned long timeleft;

	unsigned long flags;

	struct scsi_eh_save ses;

	int rtn;



	scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);

	shost->eh_action = &done;



	spin_lock_irqsave(shost->host_lock, flags);
@@ -721,18 +754,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, 
		rtn = FAILED;

	}





	/*

	 * Restore original data

	 */

	scmd->cmd_len = old_cmd_len;

	memcpy(scmd->cmnd, old_cmnd, sizeof(scmd->cmnd));

	scmd->sc_data_direction = old_data_direction;

	scmd->request_bufflen = old_bufflen;

	scmd->request_buffer = old_buffer;

	scmd->use_sg = old_use_sg;

	scmd->resid = old_resid;

	scmd->result = old_result;

	scsi_eh_restore_cmnd(scmd, &ses);

	return rtn;

}

include/scsi/scsi_eh.h

+22 −1
Original line number Diff line number Diff line 
#ifndef _SCSI_SCSI_EH_H

#define _SCSI_SCSI_EH_H



struct scsi_cmnd;

#include <scsi/scsi_cmnd.h>

struct scsi_device;

struct Scsi_Host;
@@ -65,4 +65,25 @@ extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len, 


extern int scsi_reset_provider(struct scsi_device *, int);



struct scsi_eh_save {

	int result;

	enum dma_data_direction data_direction;

	unsigned char cmd_len;

	unsigned char cmnd[MAX_COMMAND_SIZE];



	void *buffer;

	unsigned bufflen;

	unsigned short use_sg;

	int resid;



	struct scatterlist sense_sgl;

};



extern void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd,

		struct scsi_eh_save *ses, unsigned char *cmnd,

		int cmnd_size, unsigned sense_bytes);



extern void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd,

		struct scsi_eh_save *ses);



#endif /* _SCSI_SCSI_EH_H */