| Message ID | 20170907161640.30465-12-damien.lemoal@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 08, 2017 at 01:16:39AM +0900, Damien Le Moal wrote: > Using scsi_device_from_queue(), return the scsi_disk structure > associated with a request queue if the device is a disk. > Export this function to make it available to modules. > This approach may be a little over-kill, actually gendisk is the parent of request queue in kobject tree(see blk_register_queue()), that might be an easy way to retrieve disk attached to the queue.
Ming, On 9/10/17 14:16, Ming Lei wrote: > On Fri, Sep 08, 2017 at 01:16:39AM +0900, Damien Le Moal wrote: >> Using scsi_device_from_queue(), return the scsi_disk structure >> associated with a request queue if the device is a disk. >> Export this function to make it available to modules. >> > > This approach may be a little over-kill, actually gendisk is the > parent of request queue in kobject tree(see blk_register_queue()), > that might be an easy way to retrieve disk attached to the queue. Yes. It is a little extreme. I am currently preparing a V3 that will have a softer touch. Best regards.
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 1cd113df2d3a..ff9fff4de3e6 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -631,6 +631,38 @@ static void scsi_disk_put(struct scsi_disk *sdkp) mutex_unlock(&sd_ref_mutex); } +static int scsi_disk_lookup(struct device *dev, void *data) +{ + struct scsi_disk **sdkp = data; + + if (!*sdkp && dev->class == &sd_disk_class) + *sdkp = to_scsi_disk(dev); + + return 0; +} + +/** + * scsi_disk_from_queue - return scsi disk associated with a request_queue + * @q: The request queue to return the scsi disk from + * + * Return the struct scsi_disk associated with a request queue or NULL if the + * request_queue does not reference a SCSI device or a if the device is + * not a disk. + */ +struct scsi_disk *scsi_disk_from_queue(struct request_queue *q) +{ + struct scsi_device *sdev = scsi_device_from_queue(q); + struct scsi_disk *sdkp = NULL; + + if (!sdev) + return NULL; + + device_for_each_child(&sdev->sdev_gendev, &sdkp, scsi_disk_lookup); + + return sdkp; +} +EXPORT_SYMBOL_GPL(scsi_disk_from_queue); + #ifdef CONFIG_BLK_SED_OPAL static int sd_sec_submit(void *data, u16 spsp, u8 secp, void *buffer, size_t len, bool send) diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h index 3ea82c8cecd5..92113a9e2b20 100644 --- a/drivers/scsi/sd.h +++ b/drivers/scsi/sd.h @@ -126,6 +126,8 @@ static inline struct scsi_disk *scsi_disk(struct gendisk *disk) return container_of(disk->private_data, struct scsi_disk, driver); } +struct scsi_disk *scsi_disk_from_queue(struct request_queue *q); + #define sd_printk(prefix, sdsk, fmt, a...) \ (sdsk)->disk ? \ sdev_prefix_printk(prefix, (sdsk)->device, \
Using scsi_device_from_queue(), return the scsi_disk structure associated with a request queue if the device is a disk. Export this function to make it available to modules. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> --- drivers/scsi/sd.c | 32 ++++++++++++++++++++++++++++++++ drivers/scsi/sd.h | 2 ++ 2 files changed, 34 insertions(+)