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author | Stefani Seibold <stefani@seibold.net> | 2013-11-14 14:32:17 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-15 09:32:23 +0900 |
commit | 498d319bb512992ef0784c278fa03679f2f5649d (patch) | |
tree | 2793b41c3a98b858d24aa833ccc2bfb2f6d60974 /include/linux/kfifo.h | |
parent | a019e48cfbfb358786326db3dbc1c565b8f14a56 (diff) | |
download | linux-stable-498d319bb512992ef0784c278fa03679f2f5649d.tar.gz linux-stable-498d319bb512992ef0784c278fa03679f2f5649d.tar.bz2 linux-stable-498d319bb512992ef0784c278fa03679f2f5649d.zip |
kfifo API type safety
This patch enhances the type safety for the kfifo API. It is now safe
to put const data into a non const FIFO and the API will now generate a
compiler warning when reading from the fifo where the destination
address is pointing to a const variable.
As a side effect the kfifo_put() does now expect the value of an element
instead a pointer to the element. This was suggested Russell King. It
make the handling of the kfifo_put easier since there is no need to
create a helper variable for getting the address of a pointer or to pass
integers of different sizes.
IMHO the API break is okay, since there are currently only six users of
kfifo_put().
The code is also cleaner by kicking out the "if (0)" expressions.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/kfifo.h')
-rw-r--r-- | include/linux/kfifo.h | 47 |
1 files changed, 14 insertions, 33 deletions
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 10308c6a3d1c..552d51efb429 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -1,7 +1,7 @@ /* * A generic kernel FIFO implementation * - * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net> + * Copyright (C) 2013 Stefani Seibold <stefani@seibold.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -67,9 +67,10 @@ struct __kfifo { union { \ struct __kfifo kfifo; \ datatype *type; \ + const datatype *const_type; \ char (*rectype)[recsize]; \ ptrtype *ptr; \ - const ptrtype *ptr_const; \ + ptrtype const *ptr_const; \ } #define __STRUCT_KFIFO(type, size, recsize, ptrtype) \ @@ -386,16 +387,12 @@ __kfifo_int_must_check_helper( \ #define kfifo_put(fifo, val) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ - typeof((val) + 1) __val = (val); \ + typeof(*__tmp->const_type) __val = (val); \ unsigned int __ret; \ - const size_t __recsize = sizeof(*__tmp->rectype); \ + size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ - if (0) { \ - typeof(__tmp->ptr_const) __dummy __attribute__ ((unused)); \ - __dummy = (typeof(__val))NULL; \ - } \ if (__recsize) \ - __ret = __kfifo_in_r(__kfifo, __val, sizeof(*__val), \ + __ret = __kfifo_in_r(__kfifo, &__val, sizeof(__val), \ __recsize); \ else { \ __ret = !kfifo_is_full(__tmp); \ @@ -404,7 +401,7 @@ __kfifo_int_must_check_helper( \ ((typeof(__tmp->type))__kfifo->data) : \ (__tmp->buf) \ )[__kfifo->in & __tmp->kfifo.mask] = \ - *(typeof(__tmp->type))__val; \ + (typeof(*__tmp->type))__val; \ smp_wmb(); \ __kfifo->in++; \ } \ @@ -415,7 +412,7 @@ __kfifo_int_must_check_helper( \ /** * kfifo_get - get data from the fifo * @fifo: address of the fifo to be used - * @val: the var where to store the data to be added + * @val: address where to store the data * * This macro reads the data from the fifo. * It returns 0 if the fifo was empty. Otherwise it returns the number @@ -428,12 +425,10 @@ __kfifo_int_must_check_helper( \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ - typeof((val) + 1) __val = (val); \ + typeof(__tmp->ptr) __val = (val); \ unsigned int __ret; \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ - if (0) \ - __val = (typeof(__tmp->ptr))0; \ if (__recsize) \ __ret = __kfifo_out_r(__kfifo, __val, sizeof(*__val), \ __recsize); \ @@ -456,7 +451,7 @@ __kfifo_uint_must_check_helper( \ /** * kfifo_peek - get data from the fifo without removing * @fifo: address of the fifo to be used - * @val: the var where to store the data to be added + * @val: address where to store the data * * This reads the data from the fifo without removing it from the fifo. * It returns 0 if the fifo was empty. Otherwise it returns the number @@ -469,12 +464,10 @@ __kfifo_uint_must_check_helper( \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ - typeof((val) + 1) __val = (val); \ + typeof(__tmp->ptr) __val = (val); \ unsigned int __ret; \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ - if (0) \ - __val = (typeof(__tmp->ptr))NULL; \ if (__recsize) \ __ret = __kfifo_out_peek_r(__kfifo, __val, sizeof(*__val), \ __recsize); \ @@ -508,14 +501,10 @@ __kfifo_uint_must_check_helper( \ #define kfifo_in(fifo, buf, n) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ - typeof((buf) + 1) __buf = (buf); \ + typeof(__tmp->ptr_const) __buf = (buf); \ unsigned long __n = (n); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ - if (0) { \ - typeof(__tmp->ptr_const) __dummy __attribute__ ((unused)); \ - __dummy = (typeof(__buf))NULL; \ - } \ (__recsize) ?\ __kfifo_in_r(__kfifo, __buf, __n, __recsize) : \ __kfifo_in(__kfifo, __buf, __n); \ @@ -561,14 +550,10 @@ __kfifo_uint_must_check_helper( \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ - typeof((buf) + 1) __buf = (buf); \ + typeof(__tmp->ptr) __buf = (buf); \ unsigned long __n = (n); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ - if (0) { \ - typeof(__tmp->ptr) __dummy = NULL; \ - __buf = __dummy; \ - } \ (__recsize) ?\ __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \ __kfifo_out(__kfifo, __buf, __n); \ @@ -773,14 +758,10 @@ __kfifo_uint_must_check_helper( \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ - typeof((buf) + 1) __buf = (buf); \ + typeof(__tmp->ptr) __buf = (buf); \ unsigned long __n = (n); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ - if (0) { \ - typeof(__tmp->ptr) __dummy __attribute__ ((unused)) = NULL; \ - __buf = __dummy; \ - } \ (__recsize) ? \ __kfifo_out_peek_r(__kfifo, __buf, __n, __recsize) : \ __kfifo_out_peek(__kfifo, __buf, __n); \ |