RFC: Move SG_GET_SCSI_ID from sg to scsi
From: Bodo Eggert
Date: Mon Mar 06 2006 - 06:02:33 EST
I suggest moving the SG_GET_SCSI_ID ioctl from sg to scsi, since it's
generally usefull and the alternative function SCSI_IOCTL_GET_IDLUN
is limited in range (in-kernel data types may be larger) and
functionality (type, ...).
However, I have some questions about that ioctl:
- There is the concept of 8-Byte-LUNs: Are they mapped to integer LUNs?
Should the extra space in the struct sg_scsi_id be used for that?
Or should I abandon the idea and create a new IOCTL instead?
- The original IOCTL will check for sdp->detached. If the moved-to-scsi
ioctl is called, the check will be done before chaining from sg, but what
will I need to check if it's called on a non-sg device?
- Are there any (planned) changes that will conflict with this patch?
Proof-of-concept-hack (unclean):
diff -pru -x dontdiff 2.6.15.ori/drivers/scsi/scsi_ioctl.c 2.6.15/drivers/scsi/scsi_ioctl.c
--- 2.6.15.ori/drivers/scsi/scsi_ioctl.c 2006-02-08 15:10:48.000000000 +0100
+++ 2.6.15/drivers/scsi/scsi_ioctl.c 2006-03-04 21:24:13.000000000 +0100
@@ -434,6 +434,31 @@ int scsi_ioctl(struct scsi_device *sdev,
START_STOP_TIMEOUT, NORMAL_RETRIES);
case SCSI_IOCTL_GET_PCI:
return scsi_ioctl_get_pci(sdev, arg);
+ case SG_GET_SCSI_ID:
+ if (!access_ok(VERIFY_WRITE, arg, sizeof (sg_scsi_id_t)))
+ return -EFAULT;
+ else {
+ sg_scsi_id_t __user *sg_idp = arg;
+
+// if (sdp->detached)
+// return -ENODEV;
+// is the above covered by !sdev ath the
+// beginning of this function?
+ __put_user((int) sdev->host->host_no,
+ &sg_idp->host_no);
+ __put_user((int) sdev->channel,
+ &sg_idp->channel);
+ __put_user((int) sdev->id, &sg_idp->scsi_id);
+ __put_user((int) sdev->lun, &sg_idp->lun);
+ __put_user((int) sdev->type, &sg_idp->scsi_type);
+ __put_user((short) sdev->host->cmd_per_lun,
+ &sg_idp->h_cmd_per_lun);
+ __put_user((short) sdev->queue_depth,
+ &sg_idp->d_queue_depth);
+ __put_user(0, &sg_idp->unused[0]);
+ __put_user(0, &sg_idp->unused[1]);
+ return 0;
+ }
default:
if (sdev->host->hostt->ioctl)
return sdev->host->hostt->ioctl(sdev, cmd, arg);
diff -pru -x dontdiff 2.6.15.ori/drivers/scsi/sg.c 2.6.15/drivers/scsi/sg.c
--- 2.6.15.ori/drivers/scsi/sg.c 2006-02-08 15:10:48.000000000 +0100
+++ 2.6.15/drivers/scsi/sg.c 2006-03-04 22:15:15.000000000 +0100
@@ -871,29 +871,6 @@ sg_ioctl(struct inode *inode, struct fil
return 0;
case SG_GET_LOW_DMA:
return put_user((int) sfp->low_dma, ip);
- case SG_GET_SCSI_ID:
- if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
- return -EFAULT;
- else {
- sg_scsi_id_t __user *sg_idp = p;
-
- if (sdp->detached)
- return -ENODEV;
- __put_user((int) sdp->device->host->host_no,
- &sg_idp->host_no);
- __put_user((int) sdp->device->channel,
- &sg_idp->channel);
- __put_user((int) sdp->device->id, &sg_idp->scsi_id);
- __put_user((int) sdp->device->lun, &sg_idp->lun);
- __put_user((int) sdp->device->type, &sg_idp->scsi_type);
- __put_user((short) sdp->device->host->cmd_per_lun,
- &sg_idp->h_cmd_per_lun);
- __put_user((short) sdp->device->queue_depth,
- &sg_idp->d_queue_depth);
- __put_user(0, &sg_idp->unused[0]);
- __put_user(0, &sg_idp->unused[1]);
- return 0;
- }
case SG_SET_FORCE_PACK_ID:
result = get_user(val, ip);
if (result)
@@ -1072,6 +1049,7 @@ sg_ioctl(struct inode *inode, struct fil
case SCSI_IOCTL_GET_BUS_NUMBER:
case SCSI_IOCTL_PROBE_HOST:
case SG_GET_TRANSFORM:
+ case SG_GET_SCSI_ID:
if (sdp->detached)
return -ENODEV;
return scsi_ioctl(sdp->device, cmd_in, p);
diff -pru -x dontdiff 2.6.15.ori/include/scsi/scsi.h 2.6.15/include/scsi/scsi.h
--- 2.6.15.ori/include/scsi/scsi.h 2006-02-08 15:11:08.000000000 +0100
+++ 2.6.15/include/scsi/scsi.h 2006-03-04 11:11:31.000000000 +0100
@@ -245,6 +245,21 @@ struct scsi_lun {
__u8 scsi_lun[8];
};
+// copyed to scsi.h, so don't typedef it twice:
+#ifndef sg_scsi_id_t
+typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */
+ int host_no; /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */
+ int channel;
+ int scsi_id; /* scsi id of target device */
+ int lun;
+ int scsi_type; /* TYPE_... defined in scsi/scsi.h */
+ short h_cmd_per_lun;/* host (adapter) maximum commands per lun */
+ short d_queue_depth;/* device (or adapter) maximum queue length */
+ int unused[2]; /* probably find a good use, set 0 for now */
+} sg_scsi_id_t; /* 32 bytes long on i386 */
+#define sg_scsi_id_t sg_scsi_id_t
+#endif
+
/*
* MESSAGE CODES
*/
diff -pru -x dontdiff 2.6.15.ori/include/scsi/sg.h 2.6.15/include/scsi/sg.h
--- 2.6.15.ori/include/scsi/sg.h 2005-06-17 21:48:29.000000000 +0200
+++ 2.6.15/include/scsi/sg.h 2006-03-04 11:11:30.000000000 +0100
@@ -156,6 +156,8 @@ typedef struct sg_io_hdr
#define SG_INFO_MIXED_IO 0x4 /* part direct, part indirect IO */
+// copyed to scsi.h, so don't typedef it twice:
+#ifndef sg_scsi_id_t
typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */
int host_no; /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */
int channel;
@@ -166,6 +168,8 @@ typedef struct sg_scsi_id { /* used by S
short d_queue_depth;/* device (or adapter) maximum queue length */
int unused[2]; /* probably find a good use, set 0 for now */
} sg_scsi_id_t; /* 32 bytes long on i386 */
+#define sg_scsi_id_t sg_scsi_id_t
+#endif
typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
char req_state; /* 0 -> not used, 1 -> written, 2 -> ready to read */
@@ -196,8 +200,11 @@ typedef struct sg_req_info { /* used by
#define SG_GET_RESERVED_SIZE 0x2272 /* actual size of reserved buffer */
/* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */
+#ifndef SG_GET_SCSI_ID
#define SG_GET_SCSI_ID 0x2276 /* Yields fd's bus, chan, dev, lun + type */
-/* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */
+#endif
+/* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN, *
+ * but that is limited in range (/usurally/ no problem ...) */
/* Override host setting and always DMA using low memory ( <16MB on i386) */
#define SG_SET_FORCE_LOW_DMA 0x2279 /* 0-> use adapter setting, 1-> force */
-
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