Commit f27bac27 authored by Tejun Heo's avatar Tejun Heo Committed by James Bottomley
Browse files

[SCSI] sd: update index allocation and use ida instead of idr 



Update index allocation as follows.

* sd_index_idr is used only for ID allocation and mapping
  functionality is not used.  Use more memory efficient ida instead.

* idr and ida have their own locks inside them and don't need them for
  operation.  Drop it.

* index wasn't freed if probing failed after index allocation.  fix
  it.

* ida allocation should be repeated if it fails with -EAGAIN.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent ecefe8a9

drivers/scsi/sd.c

+14 −13
Original line number Diff line number Diff line
@@ -99,8 +99,7 @@ static void scsi_disk_release(struct device *cdev); 
static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);

static void sd_print_result(struct scsi_disk *, int);



static DEFINE_IDR(sd_index_idr);

static DEFINE_SPINLOCK(sd_index_lock);

static DEFINE_IDA(sd_index_ida);



/* This semaphore is used to mediate the 0->1 reference get in the

 * face of object destruction (i.e. we can't allow a get on an
@@ -1643,18 +1642,20 @@ static int sd_probe(struct device *dev) 
	if (!gd)

		goto out_free;



	if (!idr_pre_get(&sd_index_idr, GFP_KERNEL))

	do {

		if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))

			goto out_put;



	spin_lock(&sd_index_lock);

	error = idr_get_new(&sd_index_idr, NULL, &index);

	spin_unlock(&sd_index_lock);

		error = ida_get_new(&sd_index_ida, &index);

	} while (error == -EAGAIN);



	if (index >= SD_MAX_DISKS)

		error = -EBUSY;

	if (error)

		goto out_put;



	error = -EBUSY;

	if (index >= SD_MAX_DISKS)

		goto out_free_index;



	sdkp->device = sdp;

	sdkp->driver = &sd_template;

	sdkp->disk = gd;
@@ -1675,7 +1676,7 @@ static int sd_probe(struct device *dev) 
	strncpy(sdkp->dev.bus_id, sdp->sdev_gendev.bus_id, BUS_ID_SIZE);



	if (device_add(&sdkp->dev))

		goto out_put;

		goto out_free_index;



	get_device(&sdp->sdev_gendev);
@@ -1717,6 +1718,8 @@ static int sd_probe(struct device *dev) 


	return 0;



 out_free_index:

	ida_remove(&sd_index_ida, index);

 out_put:

	put_disk(gd);

 out_free:
@@ -1766,9 +1769,7 @@ static void scsi_disk_release(struct device *dev) 
	struct scsi_disk *sdkp = to_scsi_disk(dev);

	struct gendisk *disk = sdkp->disk;

	

	spin_lock(&sd_index_lock);

	idr_remove(&sd_index_idr, sdkp->index);

	spin_unlock(&sd_index_lock);

	ida_remove(&sd_index_ida, sdkp->index);



	disk->private_data = NULL;

	put_disk(disk);

CRA Git | Maintained and supported by SUSTech CRA and CCSE