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author | 2019-04-30 14:39:18 -0700 | |
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committer | 2019-06-18 19:46:17 -0400 | |
commit | f049cf1a7b6737c75884247c3f6383ef104d255a (patch) | |
tree | 61d07831c939b6c41fa4c4a5ca27e63df7047679 /drivers/scsi/scsi.c | |
parent | scsi: st: add a SPDX tag to st.c (diff) | |
download | linux-f049cf1a7b6737c75884247c3f6383ef104d255a.tar.gz linux-f049cf1a7b6737c75884247c3f6383ef104d255a.tar.bz2 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.c')
-rw-r--r-- | drivers/scsi/scsi.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 49821f138ae0..8128165a46fa 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -86,15 +86,10 @@ unsigned int scsi_logging_level; EXPORT_SYMBOL(scsi_logging_level); #endif -/* sd, scsi core and power management need to coordinate flushing async actions */ -ASYNC_DOMAIN(scsi_sd_probe_domain); -EXPORT_SYMBOL(scsi_sd_probe_domain); - /* - * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of - * asynchronous system resume operations. It is marked 'exclusive' to avoid - * being included in the async_synchronize_full() that is invoked by - * dpm_resume() + * Domain for asynchronous system resume operations. It is marked 'exclusive' + * to avoid being included in the async_synchronize_full() that is invoked by + * dpm_resume(). */ ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain); EXPORT_SYMBOL(scsi_sd_pm_domain); @@ -821,7 +816,6 @@ static void __exit exit_scsi(void) scsi_exit_devinfo(); scsi_exit_procfs(); scsi_exit_queue(); - async_unregister_domain(&scsi_sd_probe_domain); } subsys_initcall(init_scsi); |