f88022a4f6
The list_first_entry_rcu() macro is inherently unsafe because it cannot be applied to an empty list. But because RCU readers do not exclude updaters, a list might become empty between the time that list_empty() claimed it was non-empty and the time that list_first_entry_rcu() is invoked. Therefore, the list_empty() test cannot be separated from the list_first_entry_rcu() call. This commit therefore combines these to macros to create a new list_first_or_null_rcu() macro that replaces the old (and unsafe) list_first_entry_rcu() macro. This patch incorporates Paul's review comments on the previous version of this patch available here: https://lkml.org/lkml/2012/4/2/536 This patch cannot break any upstream code because list_first_entry_rcu() is not being used anywhere in the kernel (tested with grep(1)), and any external code using it is probably broken as a result of using it. Signed-off-by: Michel Machado <michel@digirati.com.br> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> CC: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
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| acpi | ||
| asm-generic | ||
| crypto | ||
| drm | ||
| keys | ||
| linux | ||
| math-emu | ||
| media | ||
| misc | ||
| mtd | ||
| net | ||
| pcmcia | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| sound | ||
| target | ||
| trace | ||
| video | ||
| xen | ||
| Kbuild | ||