tree 2714c9cf7edcbf394971cc2c929e5ab2ea34d6a6
parent 7af048dc7639db5202c56fecf2346c310647a218
author Martin Schwidefsky <schwidefsky@de.ibm.com> 1282634781 +0200
committer Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> 1282634794 +0200

[S390] fix tlb flushing vs. concurrent /proc accesses

The tlb flushing code uses the mm_users field of the mm_struct to
decide if each page table entry needs to be flushed individually with
IPTE or if a global flush for the mm_struct is sufficient after all page
table updates have been done. The comment for mm_users says "How many
users with user space?" but the /proc code increases mm_users after it
found the process structure by pid without creating a new user process.
Which makes mm_users useless for the decision between the two tlb
flusing methods. The current code can be confused to not flush tlb
entries by a concurrent access to /proc files if e.g. a fork is in
progres. The solution for this problem is to make the tlb flushing
logic independent from the mm_users field.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>