RE: [PATCH 23/26] ib: Convert qib_get_user_pages() toget_user_pages_unlocked()

[Marciniszyn, Mike]

> Convert qib_get_user_pages() to use get_user_pages_unlocked().  This
> shortens the section where we hold mmap_sem for writing and also removes
> the knowledge about get_user_pages() locking from ipath driver. We also fix
> a bug in testing pinned number of pages when changing the code.
> 

This patch and the sibling ipath patch will nominally take the mmap_sem twice where the old routine only took it once.   This is a performance issue.

Is the intent here to deprecate get_user_pages()?

I agree, the old code's lock limit test is broke and needs to be fixed.   I like the elimination of the silly wrapper routine!

Could the lock limit test be pushed into another version of the wrapper so that there is only one set of mmap_sem transactions?

Mike
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