[SCSI] scsi: Add allow_restart sysfs class attribute (a144c5ae) · Commits · 戴 / test

This is a resend of a patch I generated in response to an email sent by Ruben Faelens <parasietje@gmail.com>. His original email to linux-scsi requested a method in which he could spin down a scsi disk when not in use and have the kernel automatically spin it back up when an I/O was generated to the disk. The infrastructure to automatically spin a disk up has been in the scsi error handler for some time now, but it is not enabled by default. This patch adds an sd sysfs attribute which allows userspace to enable this behavior. Signed-off-by:

Brian King <brking@us.ibm.com> Signed-off-by:

James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/sd.c

+26 −0

Original line number	Diff line number	Diff line
		@@ -208,6 +208,23 @@ static ssize_t sd_store_cache_type(struct class_device cdev, const char buf,
		return count;
		}

		static ssize_t sd_store_allow_restart(struct class_device cdev, const char buf,
		size_t count)
		{
		struct scsi_disk *sdkp = to_scsi_disk(cdev);
		struct scsi_device *sdp = sdkp->device;

		if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

		if (sdp->type != TYPE_DISK)
		return -EINVAL;

		sdp->allow_restart = simple_strtoul(buf, NULL, 10);

		return count;
		}

		static ssize_t sd_show_cache_type(struct class_device cdev, char buf)
		{
		struct scsi_disk *sdkp = to_scsi_disk(cdev);
		@@ -223,10 +240,19 @@ static ssize_t sd_show_fua(struct class_device cdev, char buf)
		return snprintf(buf, 20, "%u\n", sdkp->DPOFUA);
		}

		static ssize_t sd_show_allow_restart(struct class_device cdev, char buf)
		{
		struct scsi_disk *sdkp = to_scsi_disk(cdev);

		return snprintf(buf, 40, "%d\n", sdkp->device->allow_restart);
		}

		static struct class_device_attribute sd_disk_attrs[] = {
		__ATTR(cache_type, S_IRUGO\|S_IWUSR, sd_show_cache_type,
		sd_store_cache_type),
		__ATTR(FUA, S_IRUGO, sd_show_fua, NULL),
		__ATTR(allow_restart, S_IRUGO\|S_IWUSR, sd_show_allow_restart,
		sd_store_allow_restart),
		__ATTR_NULL,
		};

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