| commit | e7ca1656d8124ec81c9b86944010040f1dfd8191 | |
| author | Linus Torvalds <torvalds@linux-foundation.org> | |
| Wed, 13 Jan 2010 01:57:35 +0000 (12 17:57 -0800) | ||
| committer | Greg Kroah-Hartman <gregkh@suse.de> | |
| Mon, 26 Apr 2010 14:47:57 +0000 (26 07:47 -0700) | ||
| tree | b1ab8e6e3a077e901e5fc54847896a92c839d9a6 | treesnapshot (tar.gz zip) |
| parent | f64d00b4b1486643545e9854db3a1c5d361c5d04 | commitdiff |
x86: clean up rwsem type system
commit 5d0b7235d83eefdafda300656e97d368afcafc9a upstream.
The fast version of the rwsems (the code that uses xadd) has
traditionally only worked on x86-32, and as a result it mixes different
kinds of types wildly - they just all happen to be 32-bit. We have
"long", we have "__s32", and we have "int".
To make it work on x86-64, the types suddenly matter a lot more. It can
be either a 32-bit or 64-bit signed type, and both work (with the caveat
that a 32-bit counter will only have 15 bits of effective write
counters, so it's limited to 32767 users). But whatever type you
choose, it needs to be used consistently.
This makes a new 'rwsem_counter_t', that is a 32-bit signed type. For a
64-bit type, you'd need to also update the BIAS values.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.1001121755220.17145@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit 5d0b7235d83eefdafda300656e97d368afcafc9a upstream.
The fast version of the rwsems (the code that uses xadd) has
traditionally only worked on x86-32, and as a result it mixes different
kinds of types wildly - they just all happen to be 32-bit. We have
"long", we have "__s32", and we have "int".
To make it work on x86-64, the types suddenly matter a lot more. It can
be either a 32-bit or 64-bit signed type, and both work (with the caveat
that a 32-bit counter will only have 15 bits of effective write
counters, so it's limited to 32767 users). But whatever type you
choose, it needs to be used consistently.
This makes a new 'rwsem_counter_t', that is a 32-bit signed type. For a
64-bit type, you'd need to also update the BIAS values.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.1001121755220.17145@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| arch/x86/include/asm/rwsem.h | diffblobblamehistory |