eea03c20ae
Commita7a20d1039("sd: limit the scope of the async probe domain") make the SCSI device probing run device discovery in it's own async domain. However, as a result, the partition detection was no longer synchronized by async_synchronize_full() (which, despite the name, only synchronizes the global async space, not all of them). Which in turn meant that "wait_for_device_probe()" would not wait for the SCSI partitions to be parsed. And "wait_for_device_probe()" was what the boot time init code relied on for mounting the root filesystem. Now, most people never noticed this, because not only is it timing-dependent, but modern distributions all use initrd. So the root filesystem isn't actually on a disk at all. And then before they actually mount the final disk filesystem, they will have loaded the scsi-wait-scan module, which not only does the expected wait_for_device_probe(), but also does scsi_complete_async_scans(). [ Side note: scsi_complete_async_scans() had also been partially broken, but that was fixed in commit43a8d39d01("fix async probe regression"), so that same commita7a20d1039had actually broken setups even if you used scsi-wait-scan explicitly ] Solve this problem by just moving the scsi_complete_async_scans() call into wait_for_device_probe(). Everybody who wants to wait for device probing to finish really wants the SCSI probing to complete, so there's no reason not to do this. So now "wait_for_device_probe()" really does what the name implies, and properly waits for device probing to finish. This also removes the now unnecessary extra calls to scsi_complete_async_scans(). Reported-and-tested-by: Artem S. Tashkinov <t.artem@mailcity.com> Cc: Dan Williams <dan.j.williams@gmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: James Bottomley <jbottomley@parallels.com> Cc: Borislav Petkov <bp@amd64.org> Cc: linux-scsi <linux-scsi@vger.kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
38 lines
958 B
C
38 lines
958 B
C
/*
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* scsi_wait_scan.c
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*
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* Copyright (C) 2006 James Bottomley <James.Bottomley@SteelEye.com>
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*
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* This is a simple module to wait until all the async scans are
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* complete. The idea is to use it in initrd/initramfs scripts. You
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* modprobe it after all the modprobes of the root SCSI drivers and it
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* will wait until they have all finished scanning their busses before
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* allowing the boot to proceed
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include "scsi_priv.h"
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static int __init wait_scan_init(void)
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{
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/*
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* First we need to wait for device probing to finish;
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* the drivers we just loaded might just still be probing
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* and might not yet have reached the scsi async scanning
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*/
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wait_for_device_probe();
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return 0;
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}
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static void __exit wait_scan_exit(void)
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{
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}
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MODULE_DESCRIPTION("SCSI wait for scans");
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MODULE_AUTHOR("James Bottomley");
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MODULE_LICENSE("GPL");
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late_initcall(wait_scan_init);
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module_exit(wait_scan_exit);
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