Although RCU protection would be possible during diag dump, doing
so allows for concurrent table mutations which can render the
in-table offset between individual Netlink messages invalid and
thus cause legitimate sockets to be skipped in the dump.
Since the diag dump is relatively low volume and consistency is
more important than performance, the table mutex is held during
dump.
Reported-by: Andrey Wagin <avagin@gmail.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Fixes: e341694e3e ("netlink: Convert netlink_lookup() to use RCU protected hash table")
Signed-off-by: David S. Miller <davem@davemloft.net>
Using uninitialized_var reports a false positive for "Missing blank line
after declarations".
Fix it by adding uninitialized_var to the $declaration_macros exceptions
list.
Move the macro list after $Type is declared.
Add optional prefixes to DECLARE_<FOO> and DEFINE_<BAR>
macro declarations to allow forms like:
MLX4_DECLARE_DOORBELL_LOCK
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Dotan Barak <dotanb@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Checkpatch already complains when people break up quoted strings but
it's still pretty common. One mistake that people often make is they
leave out the space character between the two strings.
This check adds around 450 new warnings and has a low rate of false
positives.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Andy Whitcroft <apw@canonical.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 89da401f6cff ("checkpatch: improve "no space after cast" test")
in -next improved the cast test for non pointer types, but also
introduced false positives for some types of static inlines.
Add a test for an open brace to the exclusions to avoid these false
positives.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Hartley Sweeten <HartleyS@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using --file mode can give false positives with MISSING_BREAK
fall-through warnings on simple but long multiple consecutive case
statements.
Look for all lines before a case statement for a switch or a statement
when using --file mode.
Fix a misspelling of preceded while there.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
c90 section "6.7.2 Type Specifiers" says:
"type specifiers may occur in any order"
That means that:
short int is the same as int short
unsigned short int is the same as int unsigned short
etc...
checkpatch currently parses only a subset of these allowed types.
For instance: "unsigned short" and "signed short" are found by
checkpatch as a specific type, but none of the or "int short" or "int
signed short" variants are found.
Add another table for the "kernel style misordered" variants.
Add this misordered table to the findable types.
Warn when the misordered style is used.
This improves the "Missing a blank line after declarations" test as it
depends on the correct parsing of the $Declare variable which looks for
"$Type $Ident;" (ie: declarations like "int foo;").
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current generic types are unsigned or unspecified. Add signed to the
types.
Reorder the types to find the longest match first.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
short int is one of the 6.7.2 c90 types.
Find it appropriately.
This fixes a defect in checkpatch where it suggests that a line break
after declaration is required using an input like:
int foo;
short int bar;
Without this change, it warns on the short int line.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Hartley Sweeten <HartleyS@visionengravers.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All the various for_each loop macros were not tested for trailing brace
on the following lines and for bad indentation.
Add them.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Greg KH <gregkh@linuxfoundation.org>
Cc: Andy Whitcroft <apw@canonical.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add --fix corrections for ELSE_AFTER_BRACE and WHILE_AFTER_BRACE
misuses.
if (x) {
...
}
else {
...
}
is corrected to
if (x) {
...
} else {
...
}
and
do {
...
}
while (x);
is corrected to
do {
...
} while (x);
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Style misuses of these types are corrected:
typedef struct foo
{
int bar;
};
int foo(int bar) { return bar+1;
}
int foo(int bar) {
return bar+1;
}
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I copied the which subroutine from get_maintainer.pl.
Unfortunately, get_maintainer uses a 4 space indentation so use the
proper tab indentation instead.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Neaten the uses of patch/file line insertions or deletions. Hide the
mechanism used.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This can be valuable to insert or delete blank lines as well as fix
misplaced brace or else uses.
Store indexes of lines to be added/deleted and the new lines.
When creating the --fix file, insert or delete the appropriate lines and
update the patch range information.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make the fix code a bit easier to read.
This should also start to allow an easier mechanism to insert/delete
lines eventually too.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using break; after a goto or return is unnecessary so emit a warning
when the break is at the same indent level.
So this emits a warning on:
switch (foo) {
case 1:
goto err;
break;
}
but not on:
switch (foo) {
case 1:
if (bar())
goto err;
break;
}
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Whenever files are added, moved, or deleted, the MAINTAINERS file
patterns can be out of sync or outdated.
To try to keep MAINTAINERS more up-to-date, add a one-time warning
whenever a patch does any of those.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit logs have various forms of commit id references.
Try to standardize on a 12 character long lower case commit id along
with a description of parentheses and the quoted subject line.
ie: commit 0123456789ab ("commit description")
If git and a git tree exists, look up the commit id and emit the
appropriate line as part of the message.
Signed-off-by: Joe Perches <joe@perches.com>
Requested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoid matching allocs that appear to be known small multiplications of a
sizeof with a constant because gcc as of 4.8 cannot optimize the code in
a calloc() exactly the same way as an alloc().
Look for numeric constants or what appear to be upper case only macro
#defines.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Theodore Ts'o <tytso@mit.edu>
Original-patch-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This --strict test previously worked only for what appeared to be cast
to pointer types.
Make it work for all casts.
Also, there's no reason to show the previous line for this type of
message, so don't.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch's $Type variable does not match declarations of multiple
const * types.
This can produce false positives for things like:
$ ./scripts/checkpatch.pl -f drivers/staging/comedi/comedidev.h
WARNING: Missing a blank line after declarations
#60: FILE: drivers/staging/comedi/comedidev.h:60:
+ const struct comedi_lrange *range_table;
+ const struct comedi_lrange *const *range_table_list;
Fix the $Type variable to support matching multiple "* const" uses.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Hartley Sweeten <HartleyS@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Parentheses around &(foo->bar) and *(foo->bar) are unnecessary. Emit a
--strict only message on these uses.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Editing Kconfig dependencies can emit unnecessary messages about missing
or too short help entries.
Only emit the message when adding help sections to Kconfig files.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make it consistent with the other missing or multiple blank line tests.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Multiple consecutive blank lines waste screen space. Emit a --strict
only message with these blank lines.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a --strict test asking for a blank line after
function/struct/union/enum declarations.
Allow exceptions for several attributes and macro uses.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This might help a kernel hacker think twice before blindly adding a
newline.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are some patches created by git format-patch that when scanned by
checkpatch report errors on lines like
To: address.tld
This is a checkpatch false positive.
Improve the logic a bit to ignore folded email headers to avoid emitting
these messages.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a function pointer declaration check to the test for blank line
needed after declarations.
Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Bruce W Allan <bruce.w.allan@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A single escaped constant char is not a complex macro.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using an else following a break or return can unnecessarily indent code
blocks.
ie:
for (i = 0; i < 100; i++) {
int foo = bar();
if (foo < 1)
break;
else
usleep(1);
}
is generally better written as:
for (i = 0; i < 100; i++) {
int foo = bar();
if (foo < 1)
break;
usleep(1);
}
Warn when a bare else statement is preceded by a break or return
indented 1 tab more than the else.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Logging messages that show some type of "out of memory" error are
generally unnecessary as there is a generic message and a stack dump
done by the memory subsystem.
These messages generally increase kernel size without much added value.
Emit a warning on these types of messages.
This test looks for any inserted message function, then looks at the
previous line for an "if (!foo)" or "if (foo == NULL)" test and then
looks at the preceding statement for an allocation function like "foo =
kmalloc()"
ie: this code matches:
foo = kmalloc();
if (foo == NULL) {
printk("Out of memory\n");
return -ENOMEM;
}
This test is very crude and incomplete.
This test can miss quite a lot of of OOM messages that do not have this
specific form.
ie: this code does not match:
foo = kmalloc();
if (!foo) {
rtn = -ENOMEM;
printk("Out of memory!\n");
goto out;
}
This test could also be a false positive when the logging message itself
does not specify anything about memory, but I did not find any false
positives in my limited testing.
spatch could be a better solution but correctness seems non-trivial for
that tool too.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Apparently, bitmap_andnot is supposed to return whether the new bitmap
is empty. But it didn't take potential garbage bits in the last word
into account.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Apparently, bitmap_and is supposed to return whether the new bitmap is
empty. But it didn't take potential garbage bits in the last word into
account.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no guarantee that *src does not contain garbage bits outside
the lower nbits, so we need to mask it before the shift-and-assign.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__reg_op(..., REG_OP_ALLOC) always returns 0, so we might as well use that
and save an instruction.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changing the pos parameter of __reg_op to unsigned allows the compiler
to generate slightly smaller and simpler code. Also update its callers
bitmap_*_region to receive and pass unsigned int. The return types of
bitmap_find_free_region and bitmap_allocate_region are still int to
allow a negative error code to be returned. An int is certainly capable
of representing any realistic return value.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A few lines above, it was stated that positions for non-set bits are
mapped to -1, which is obviously also what the code does.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want len to be the index of the first '\n', or the length of the
string if there is no newline. This is a good example of the usefulness
of strchrnul(). Use that instead, thus eliminating a branch and a call
to strlen().
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "start" is non-negative.
Also, use the names "start" and "len" for the two parameters for
consistency with bitmap_set.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "start" is non-negative.
Also, use the names "start" and "len" for the two parameters in both
header file and implementation, instead of the previous mix.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
I didn't change the return type, since that might change the semantics
of some expression containing a call to bitmap_weight(). Certainly an
int is capable of holding the result.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change is only for consistency with the changes to the other
bitmap_* functions; it doesn't change the size of the generated code:
inside BITS_TO_LONGS there is a sizeof(long), which causes bits to be
interpreted as unsigned anyway.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since the extra bits are "don't care", there is no reason to mask the
last word to the used bits when complementing. This shaves off yet a
few bytes.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many functions in lib/bitmap.c start with an expression such as lim =
bits/BITS_PER_LONG. Since bits has type (signed) int, and since gcc
cannot know that it is in fact non-negative, it generates worse code
than it could. These patches, mostly consisting of changing various
parameters to unsigned, gives a slight overall code reduction:
add/remove: 1/1 grow/shrink: 8/16 up/down: 251/-414 (-163)
function old new delta
tick_device_uses_broadcast 335 425 +90
__irq_alloc_descs 498 554 +56
__bitmap_andnot 73 115 +42
__bitmap_and 70 101 +31
bitmap_weight - 11 +11
copy_hugetlb_page_range 752 762 +10
follow_hugetlb_page 846 854 +8
hugetlb_init 1415 1417 +2
hugetlb_nrpages_setup 130 131 +1
hugetlb_add_hstate 377 376 -1
bitmap_allocate_region 82 80 -2
select_task_rq_fair 2202 2191 -11
hweight_long 66 55 -11
__reg_op 230 219 -11
dm_stats_message 2849 2833 -16
bitmap_parselist 92 74 -18
__bitmap_weight 115 97 -18
__bitmap_subset 153 129 -24
__bitmap_full 128 104 -24
__bitmap_empty 120 96 -24
bitmap_set 179 149 -30
bitmap_clear 185 155 -30
__bitmap_equal 136 105 -31
__bitmap_intersects 148 108 -40
__bitmap_complement 109 67 -42
tick_device_setup_broadcast_func.isra 81 - -81
[The increases in __bitmap_and{,not} are due to bug fixes 17/18,18/18.
No idea why bitmap_weight suddenly appears.] While 163 bytes treewide is
insignificant, I believe the bitmap functions are often called with
locks held, so saving even a few cycles might be worth it.
While making these changes, I found a few other things that might be
worth including. 16,17,18 are actual bug fixes. The rest shouldn't
change the behaviour of any of the functions, provided no-one passed
negative nbits values. If something should come up, it should be fairly
bisectable.
A few issues I thought about, but didn't know what to do with:
* Many of the functions misbehave if nbits is compile-time 0; the
out-of-line functions generally handle 0 correctly. bitmap_fill() is
particularly bad, whether the 0 is known at compile time or not. It
would probably be nice to add detection of at least compile-time 0 and
handle that appropriately.
* I didn't change __bitmap_shift_{left,right} to use unsigned because I
want to fully understand why the algorithm works before making that
change. However, AFAICT, they behave correctly for all (positive) shift
amounts. This is not the case for the small_const_nbits versions. If
for example nbits = n = BITS_PER_LONG, the shift operators turn into
no-ops (at least on x86), so one get *dst = *src, whereas one would
expect to get *dst=0. That difference in behaviour is somewhat
annoying.
This patch (of 18):
The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thomas Graf