Messages in this thread | | | Subject | Re: How to register block device as read-only | From | Bernd Petrovitsch <> | Date | Sat, 28 Jul 2007 13:36:14 +0200 |
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On Fri, 2007-07-27 at 13:07 -0500, beck0778@umn.edu wrote: > Hello, > > In a block device driver, how do you tell the kernel that your block device > is read-only? Is it in the registration of the gendisk, or is there an > ioctl I should be catching to inform the kernel (and user) that this disk > is read-only?
Unless I misunderstand the question, the "write" and "writev" function of the "struct file_operations" should return an appropriate error value (which is here -EACCES). You may think of returning an error in the "open" if someone wants to open it to write to it (so that the must open it read-only). But I don't know if that is common practice or not (or even disliked) as it may interfere with not properly implemented tools which open devices read-write even if they never write to it.
Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services
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