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| author | Bart Van Assche <bvanassche@acm.org> | 2019-04-30 23:39:18 +0200 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2019-06-19 01:46:17 +0200 |
| commit | f049cf1a7b6737c75884247c3f6383ef104d255a (patch) | |
| tree | 61d07831c939b6c41fa4c4a5ca27e63df7047679 /drivers/scsi/scsi_pm.c | |
| parent | scsi: st: add a SPDX tag to st.c (diff) | |
| download | linux-f049cf1a7b6737c75884247c3f6383ef104d255a.tar.xz linux-f049cf1a7b6737c75884247c3f6383ef104d255a.zip | |
scsi: sd: Rely on the driver core for asynchronous probing
As explained during the 2018 LSF/MM session about increasing SCSI disk
probing concurrency, the problems with the current probing approach are as
follows:
- The driver core is unaware of asynchronous SCSI LUN probing.
wait_for_device_probe() waits for all asynchronous probes except
asynchronous SCSI disk probes.
- There is unnecessary serialization between sd_probe() and sd_remove().
This can lead to a deadlock.
Hence this patch that modifies the sd driver such that it uses the driver
core framework for asynchronous probing. The async domain and
get_device()/put_device() pairs that became superfluous due to this change
are removed.
This patch does not affect the time needed for loading the scsi_debug
kernel module with parameters delay=0 and max_luns=256.
This patch depends on commit ef0ff68351be ("driver core: Probe devices
asynchronously instead of the driver") that went upstream in kernel version
v5.1-rc1.
Cc: Lee Duncan <lduncan@suse.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi_pm.c')
| -rw-r--r-- | drivers/scsi/scsi_pm.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c index 3a5dfbb81622..cbdf61c1d667 100644 --- a/drivers/scsi/scsi_pm.c +++ b/drivers/scsi/scsi_pm.c @@ -176,11 +176,7 @@ static int scsi_bus_resume_common(struct device *dev, static int scsi_bus_prepare(struct device *dev) { - if (scsi_is_sdev_device(dev)) { - /* sd probing uses async_schedule. Wait until it finishes. */ - async_synchronize_full_domain(&scsi_sd_probe_domain); - - } else if (scsi_is_host_device(dev)) { + if (scsi_is_host_device(dev)) { /* Wait until async scanning is finished */ scsi_complete_async_scans(); } |