Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH] macintosh: Explicitly set llseek to no_llseek in ans-lcd | Date | Mon, 16 Nov 2009 13:09:47 +0100 |
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On Monday 16 November 2009, Christoph Hellwig wrote: > As mentioned before making generic_file_llseek the new default is > probably a bad idea. The majority of our file_operations instances > don't actually support seeking, so no_llseek should become the new > default if you spend some effort on converting things. Anything that > wants to allow seeking will have to set a llseek method. This also > mirrors what we do for other file operations. None of the major ones > has a non-trivial default, it's either silently succeeding for a > selected few like open or release or returning an error for operatings > that actually do something like read and write.
Ok, good point.
Do you think we should also prevent pread/pwrite for devices without an llseek operation, like nonseekable_open does? I guess that would be consistent.
Then there is the point that (I forgot who) brought up that changing code to do no_llseek is actually an ABI change. Even if the file position is never used anywhere, some random user application might expect a chardev not to return an error when its llseek method is called, resulting in regressions.
Arnd <><
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