From 26cf591e6dfc0d07495b7bcf20a557b316811f00 Mon Sep 17 00:00:00 2001 From: Douglas Gilbert Date: Sat, 18 Oct 2014 22:11:21 +0200 Subject: [PATCH] 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_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_SCSI_RESET, &val); Signed-off-by: Douglas Gilbert Reviewed-by: Jeremy Linton Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig --- drivers/scsi/scsi_error.c | 10 ++++++++++ drivers/scsi/scsi_ioctl.c | 20 +++++++++++++------- drivers/scsi/sg.c | 17 +++++++++++------ include/scsi/scsi_eh.h | 5 +++++ include/scsi/sg.h | 5 ++++- 5 files changed, 43 insertions(+), 14 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index bc5ff6ff9c79..0ed666112b4f 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -2366,8 +2366,18 @@ scsi_reset_provider(struct scsi_device *dev, int flag) break; /* FALLTHROUGH */ case SCSI_TRY_RESET_HOST: + case SCSI_TRY_RESET_HOST | SCSI_TRY_RESET_NO_ESCALATE: rtn = scsi_try_host_reset(scmd); break; + case SCSI_TRY_RESET_DEVICE | SCSI_TRY_RESET_NO_ESCALATE: + rtn = scsi_try_bus_device_reset(scmd); + break; + case SCSI_TRY_RESET_TARGET | SCSI_TRY_RESET_NO_ESCALATE: + rtn = scsi_try_target_reset(scmd); + break; + case SCSI_TRY_RESET_BUS | SCSI_TRY_RESET_NO_ESCALATE: + rtn = scsi_try_bus_reset(scmd); + break; default: rtn = FAILED; } 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; diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 60354449d9ed..fe44c14f551e 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -847,7 +847,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg) { void __user *p = (void __user *)arg; int __user *ip = p; - int result, val, read_only; + int result, val, val2, read_only; Sg_device *sdp; Sg_fd *sfp; Sg_request *srp; @@ -1082,27 +1082,32 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg) result = get_user(val, ip); 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 (SG_SCSI_RESET_NOTHING == val) 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(sdp->device, val) == + return (scsi_reset_provider(sdp->device, val2) == SUCCESS) ? 0 : -EIO; case SCSI_IOCTL_SEND_COMMAND: if (atomic_read(&sdp->detaching)) diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h index 06a8790893ef..49af14ad5288 100644 --- a/include/scsi/scsi_eh.h +++ b/include/scsi/scsi_eh.h @@ -62,11 +62,16 @@ extern void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq); /* * Reset request from external source + * Note: if SCSI_TRY_RESET_DEVICE fails then it will escalate to + * SCSI_TRY_RESET_TARGET which if it fails will escalate to + * SCSI_TRY_RESET_BUS which if it fails will escalate to SCSI_TRY_RESET_HOST. + * To prevent escalation OR with SCSI_TRY_RESET_NO_ESCALATE. */ #define SCSI_TRY_RESET_DEVICE 1 #define SCSI_TRY_RESET_BUS 2 #define SCSI_TRY_RESET_HOST 3 #define SCSI_TRY_RESET_TARGET 4 +#define SCSI_TRY_RESET_NO_ESCALATE 0x100 /* OR-ed to prior defines */ extern int scsi_reset_provider(struct scsi_device *, int); diff --git a/include/scsi/sg.h b/include/scsi/sg.h index 750e5db7c6bf..3afec7032448 100644 --- a/include/scsi/sg.h +++ b/include/scsi/sg.h @@ -164,12 +164,15 @@ typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */ /* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */ #define SG_SCSI_RESET 0x2284 -/* Associated values that can be given to SG_SCSI_RESET follow */ +/* Associated values that can be given to SG_SCSI_RESET follow. + * SG_SCSI_RESET_NO_ESCALATE may be OR-ed to the _DEVICE, _TARGET, _BUS + * or _HOST reset value so only that action is attempted. */ #define SG_SCSI_RESET_NOTHING 0 #define SG_SCSI_RESET_DEVICE 1 #define SG_SCSI_RESET_BUS 2 #define SG_SCSI_RESET_HOST 3 #define SG_SCSI_RESET_TARGET 4 +#define SG_SCSI_RESET_NO_ESCALATE 0x100 /* synchronous SCSI command ioctl, (only in version 3 interface) */ #define SG_IO 0x2285 /* similar effect as write() followed by read() */ -- 2.30.2