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authorDouglas Gilbert <dgilbert@interlog.com>2014-10-18 22:11:21 +0200
committerChristoph Hellwig <hch@lst.de>2014-11-12 11:15:54 +0100
commit26cf591e6dfc0d07495b7bcf20a557b316811f00 (patch)
treeaaebbfe8c9764f981f2fa540b6ae20c79dce55af /drivers/scsi/scsi_ioctl.c
parent678e27573237a0b065defdf99e5070c9b0c403c3 (diff)
downloadlinux-26cf591e6dfc0d07495b7bcf20a557b316811f00.tar.bz2
scsi: add SG_SCSI_RESET_NO_ESCALATE flag to SG_SCSI_RESET ioctl
Further to a January 2013 thread titled: "[PATCH] SG_SCSI_RESET ioctl should only perform requested operation" by Jeremy Linton a patch (v3) is presented that expands the existing ioctl to include "no_escalate" versions to the existing resets. This requires no changes to SCSI low level drivers (LLDs); it adds several more finely tuned reset options to the user space. For example: /* This call remains the same, with the same escalating semantics * if the device (LU) reset fail. That is: on failure to try a * target reset and if that fails, try a bus reset, and if that fails * try a host (i.e. LLD) reset. */ val = SG_SCSI_RESET_DEVICE; res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val); /* What follows is a new option introduced by this patch series. Only * a device reset is attempted. If that fails then an appropriate * error code is provided. N.B. There is no reset escalation. */ val = SG_SCSI_RESET_DEVICE | SG_SCSI_RESET_NO_ESCALATE; res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val); Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Reviewed-by: Jeremy Linton <jlinton@tributary.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/scsi/scsi_ioctl.c')
-rw-r--r--drivers/scsi/scsi_ioctl.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
index 1aaaf43c6803..12fe676d1343 100644
--- a/drivers/scsi/scsi_ioctl.c
+++ b/drivers/scsi/scsi_ioctl.c
@@ -285,13 +285,14 @@ EXPORT_SYMBOL(scsi_ioctl);
* scsi_nonblockable_ioctl() - Handle SG_SCSI_RESET
* @sdev: scsi device receiving ioctl
* @cmd: Must be SC_SCSI_RESET
- * @arg: pointer to int containing SG_SCSI_RESET_{DEVICE,BUS,HOST}
+ * @arg: pointer to int containing SG_SCSI_RESET_{DEVICE,TARGET,BUS,HOST}
+ * possibly OR-ed with SG_SCSI_RESET_NO_ESCALATE
* @ndelay: file mode O_NDELAY flag
*/
int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
void __user *arg, int ndelay)
{
- int val, result;
+ int val, val2, result;
/* The first set of iocts may be executed even if we're doing
* error processing, as long as the device was opened
@@ -307,27 +308,32 @@ int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
result = get_user(val, (int __user *)arg);
if (result)
return result;
+ if (val & SG_SCSI_RESET_NO_ESCALATE) {
+ val &= ~SG_SCSI_RESET_NO_ESCALATE;
+ val2 = SCSI_TRY_RESET_NO_ESCALATE;
+ } else
+ val2 = 0;
if (val == SG_SCSI_RESET_NOTHING)
return 0;
switch (val) {
case SG_SCSI_RESET_DEVICE:
- val = SCSI_TRY_RESET_DEVICE;
+ val2 |= SCSI_TRY_RESET_DEVICE;
break;
case SG_SCSI_RESET_TARGET:
- val = SCSI_TRY_RESET_TARGET;
+ val2 |= SCSI_TRY_RESET_TARGET;
break;
case SG_SCSI_RESET_BUS:
- val = SCSI_TRY_RESET_BUS;
+ val2 |= SCSI_TRY_RESET_BUS;
break;
case SG_SCSI_RESET_HOST:
- val = SCSI_TRY_RESET_HOST;
+ val2 |= SCSI_TRY_RESET_HOST;
break;
default:
return -EINVAL;
}
if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
return -EACCES;
- return (scsi_reset_provider(sdev, val) ==
+ return (scsi_reset_provider(sdev, val2) ==
SUCCESS) ? 0 : -EIO;
}
return -ENODEV;