[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: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 22 insertions, 1 deletions

diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
index c5c0f6762a01..44224ba4dd90 100644
--- a/include/scsi/scsi_eh.h
+++ b/include/scsi/scsi_eh.h
@@ -1,7 +1,7 @@
 #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 */