Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Browse files

futex: documentation: fix inconsistent description of futex list_op_p…

…ending

Strictly speaking list_op_pending points to the 'lock entry', not the
'lock word' (which is actually at 'offset' from 'lock entry').  We can
infer this based on reading the code in kernel/futex.c:

	    struct robust_list __user *entry, *next_entry, *pending;
		...
            if (fetch_robust_entry(&pending, &head->list_op_pending, &pip))
                    return;
            ...
            if (pending)
                    handle_futex_death((void __user *)pending + futex_offset,
                                       curr, pip);

Which is also consistent with the rest of the docs on robust futex lists.

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linuxtronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  • Loading branch information...
commit 26c369dada267d3df1beb86cf89b865ac1178a7f 1 parent 665c774
Matt Helsley authored committed
Showing with 2 additions and 2 deletions.
  1. +2 −2 Documentation/robust-futex-ABI.txt
View
4 Documentation/robust-futex-ABI.txt
@@ -135,7 +135,7 @@ manipulating this list), the user code must observe the following
protocol on 'lock entry' insertion and removal:
On insertion:
- 1) set the 'list_op_pending' word to the address of the 'lock word'
+ 1) set the 'list_op_pending' word to the address of the 'lock entry'
to be inserted,
2) acquire the futex lock,
3) add the lock entry, with its thread id (TID) in the bottom 29 bits
@@ -143,7 +143,7 @@ On insertion:
4) clear the 'list_op_pending' word.
On removal:
- 1) set the 'list_op_pending' word to the address of the 'lock word'
+ 1) set the 'list_op_pending' word to the address of the 'lock entry'
to be removed,
2) remove the lock entry for this lock from the 'head' list,
2) release the futex lock, and
Please sign in to comment.
Something went wrong with that request. Please try again.