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| author | Christoph Hellwig <hch@lst.de> | 2014-01-22 18:29:29 +0400 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-07-25 15:43:43 +0400 |
| commit | 74665016086615bbaa3fa6f83af410a0a4e029ee (patch) | |
| tree | 9f9d8a692bec91dce69fd303eeedf16c35b41ac6 /drivers/scsi/scsi_sysfs.c | |
| parent | 7ae65c0f9646c29432b69580b80e08632e6cd813 (diff) | |
| download | linux-74665016086615bbaa3fa6f83af410a0a4e029ee.tar.xz | |
scsi: convert host_busy to atomic_t
Avoid taking the host-wide host_lock to check the per-host queue limit.
Instead we do an atomic_inc_return early on to grab our slot in the queue,
and if necessary decrement it after finishing all checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
Diffstat (limited to 'drivers/scsi/scsi_sysfs.c')
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 5f36788705ba..de57b8bca7be 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -334,7 +334,6 @@ store_shost_eh_deadline(struct device *dev, struct device_attribute *attr, static DEVICE_ATTR(eh_deadline, S_IRUGO | S_IWUSR, show_shost_eh_deadline, store_shost_eh_deadline); shost_rd_attr(unique_id, "%u\n"); -shost_rd_attr(host_busy, "%hu\n"); shost_rd_attr(cmd_per_lun, "%hd\n"); shost_rd_attr(can_queue, "%hd\n"); shost_rd_attr(sg_tablesize, "%hu\n"); @@ -344,6 +343,14 @@ shost_rd_attr(prot_capabilities, "%u\n"); shost_rd_attr(prot_guard_type, "%hd\n"); shost_rd_attr2(proc_name, hostt->proc_name, "%s\n"); +static ssize_t +show_host_busy(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct Scsi_Host *shost = class_to_shost(dev); + return snprintf(buf, 20, "%d\n", atomic_read(&shost->host_busy)); +} +static DEVICE_ATTR(host_busy, S_IRUGO, show_host_busy, NULL); + static struct attribute *scsi_sysfs_shost_attrs[] = { &dev_attr_unique_id.attr, &dev_attr_host_busy.attr, |