scsi: always increment reference count (dc4515ea) · Commits · 戴 / test

James reported: > After module: Remove stop_machine from module unloading, > module_refcount() is returning (unsigned long)-1 when called from within > a routine that runs in module_exit. This is confusing the scsi device > put code which is coded to detect a module_refcount() of zero for > running within a module exit routine and not try to do another > module_put. The fix is to restore the original behaviour of > module_refcount() and return zero if we're running inside an exit > routine. The correct fix is to turn try_module_get() into __module_get(), and always do the module_put(). Acked-by:

James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by:

Rusty Russell <rusty@rustcorp.com.au>

drivers/scsi/scsi.c

+3 −10

Original line number	Diff line number	Diff line
		@@ -986,9 +986,9 @@ int scsi_device_get(struct scsi_device *sdev)
		return -ENXIO;
		if (!get_device(&sdev->sdev_gendev))
		return -ENXIO;
		/* We can fail this if we're doing SCSI operations
		/* We can fail try_module_get if we're doing SCSI operations
		* from module exit (like cache flush) */
		try_module_get(sdev->host->hostt->module);
		__module_get(sdev->host->hostt->module);

		return 0;
		}
		@@ -1004,14 +1004,7 @@ EXPORT_SYMBOL(scsi_device_get);
		*/
		void scsi_device_put(struct scsi_device *sdev)
		{
		#ifdef CONFIG_MODULE_UNLOAD
		struct module *module = sdev->host->hostt->module;

		/* The module refcount will be zero if scsi_device_get()
		* was called from a module removal routine */
		if (module && module_refcount(module) != 0)
		module_put(module);
		#endif
		module_put(sdev->host->hostt->module);
		put_device(&sdev->sdev_gendev);
		}
		EXPORT_SYMBOL(scsi_device_put);

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