On Wed, 5 Mar 2008, Stefan Richter wrote:
> > Would it be acceptable to add a similar pair of callbacks to the host
> > template, invoked by the upper-level driver's open and release
> > routines?
>
> This would actually be nice for that sbp2 thing which I mentioned as well.
James and Stefan, what do you think of this patch?
(Unfortunately it won't quite apply as is, because it touches a region
of documentation that was changed by the SCSI dynamic power management
patch.)
Alan Stern
--------------------------------------------------------------------
This patch (as1050b) adds two new methods to the SCSI host template
structure. These methods are called to notify lower-level drivers
when a block device below one of their hosts has been opened or
released.
This information is useful for host drivers that want to know whether
a device on one of its buses contains a mounted filesystem. The
open/release information isn't quite the same as mount/unmount, but it
will suffice.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
Index: usb-2.6/Documentation/scsi/scsi_mid_low_api.txt
===================================================================
--- usb-2.6.orig/Documentation/scsi/scsi_mid_low_api.txt
+++ usb-2.6/Documentation/scsi/scsi_mid_low_api.txt
@@ -785,6 +785,8 @@ Summary:
autoresume - perform dynamic (runtime) host resume
autosuspend - perform dynamic (runtime) host suspend
bios_param - fetch head, sector, cylinder info for a disk
+ blockdev_open - notify the host about a block-device open
+ blockdev_release - notify the host about a block-device release
detect - detects HBAs this driver wants to control
eh_timed_out - notify the host that a command timer expired
eh_abort_handler - abort given command
@@ -882,6 +884,48 @@ Details:
/**
+ * blockdev_open - notify the host about a block-device open
+ * @sdev: the SCSI device being opened
+ * @disk: the gendisk corresponding to the block device
+ *
+ * Block device opens occur primarily when a filesystem on the
+ * device is mounted (although they crop up occasionally at other
+ * times, such as when a partition table is edited). An LLD
+ * can define this function and blockdev_release below to keep
+ * track of whether or not a device below one of its hosts has
+ * been mounted.
+ *
+ * Locks: none
+ *
+ * Calling context: process
+ *
+ * Optionally defined in: LLD
+ **/
+ void blockdev_open(struct scsi_device *sdev, struct gendisk *disk)
+
+
+/**
+ * blockdev_release - notify the host about a block-device release
+ * @sdev: the SCSI device being released
+ * @disk: the gendisk corresponding to the block device
+ *
+ * Block device releases occur primarily when a filesystem on the
+ * device is unmounted (although they crop up occasionally at other
+ * times, such as when a partition table is edited). An LLD
+ * can define this function and blockdev_open above to keep
+ * track of whether or not a device below one of its hosts has
+ * been mounted.
+ *
+ * Locks: none
+ *
+ * Calling context: process
+ *
+ * Optionally defined in: LLD
+ **/
+ void blockdev_release(struct scsi_device *sdev, struct gendisk *disk)
+
+
+/**
* detect - detects HBAs this driver wants to control
* @shtp: host template for this driver.
*
Index: usb-2.6/include/scsi/scsi_host.h
===================================================================
--- usb-2.6.orig/include/scsi/scsi_host.h
+++ usb-2.6/include/scsi/scsi_host.h
@@ -306,6 +306,27 @@ struct scsi_host_template {
void (* scan_start)(struct Scsi_Host *);
/*
+ * If the host driver wants to know about block-device open
+ * calls, it can fill in this function. Note that these calls
+ * are made only for the first opener, not for opens that occur
+ * when the device is already open.
+ *
+ * Status: OPTIONAL
+ */
+ void (* blockdev_open)(struct scsi_device *, struct gendisk *);
+
+ /*
+ * If the host driver wants to know about block-device release
+ * calls, it can fill in this function. Note that these calls
+ * are made only for the last closer, not for closes that leave
+ * the device still open (i.e., these exactly balance the
+ * block-device open calls).
+ *
+ * Status: OPTIONAL
+ */
+ void (* blockdev_release)(struct scsi_device *, struct gendisk *);
+
+ /*
* Fill in this function to allow the queue depth of this host
* to be changeable (on a per device basis). Returns either
* the current queue depth setting (may be different from what
Index: usb-2.6/drivers/scsi/sd.c
===================================================================
--- usb-2.6.orig/drivers/scsi/sd.c
+++ usb-2.6/drivers/scsi/sd.c
@@ -606,6 +606,9 @@ static int sd_open(struct inode *inode,
if (!scsi_device_online(sdev))
goto error_out;
+ if (sdev->host->hostt->blockdev_open)
+ (sdev->host->hostt->blockdev_open)(sdev, disk);
+
if (!sdkp->openers++ && sdev->removable) {
if (scsi_block_when_processing_errors(sdev))
scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
@@ -642,6 +645,9 @@ static int sd_release(struct inode *inod
scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
}
+ if (sdev->host->hostt->blockdev_release)
+ (sdev->host->hostt->blockdev_release)(sdev, disk);
+
/*
* XXX and what if there are packets in flight and this close()
* XXX is followed by a "rmmod sd_mod"?
Index: usb-2.6/drivers/scsi/sr.c
===================================================================
--- usb-2.6.orig/drivers/scsi/sr.c
+++ usb-2.6/drivers/scsi/sr.c
@@ -473,13 +473,17 @@ static int sr_block_open(struct inode *i
{
struct gendisk *disk = inode->i_bdev->bd_disk;
struct scsi_cd *cd;
+ struct scsi_device *sdev;
int ret = 0;
if(!(cd = scsi_cd_get(disk)))
return -ENXIO;
+ sdev = cd->device;
if((ret = cdrom_open(&cd->cdi, inode, file)) != 0)
scsi_cd_put(cd);
+ else if (sdev->host->hostt->blockdev_open)
+ (sdev->host->hostt->blockdev_open)(sdev, disk);
return ret;
}
@@ -487,11 +491,16 @@ static int sr_block_open(struct inode *i
static int sr_block_release(struct inode *inode, struct file *file)
{
int ret;
- struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
+ struct gendisk *disk = inode->i_bdev->bd_disk;
+ struct scsi_cd *cd = scsi_cd(disk);
+ struct scsi_device *sdev = cd->device;
+
ret = cdrom_release(&cd->cdi, file);
if(ret)
return ret;
-
+
+ if (sdev->host->hostt->blockdev_release)
+ (sdev->host->hostt->blockdev_release)(sdev, disk);
scsi_cd_put(cd);
return 0;
--
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