diff options
| author | David Howells <dhowells@redhat.com> | 2006-12-08 02:37:49 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-08 08:28:51 -0800 |
| commit | f0d1b0b30d250a07627ad8b9fbbb5c7cc08422e8 (patch) | |
| tree | 0aa5379150574374351fb92af7881a48dbfcf2ce /drivers/infiniband/ulp | |
| parent | b3d7ae5f47a58a9f7b152deeaf7daa1fc558a8f1 (diff) | |
[PATCH] LOG2: Implement a general integer log2 facility in the kernel
This facility provides three entry points:
ilog2() Log base 2 of unsigned long
ilog2_u32() Log base 2 of u32
ilog2_u64() Log base 2 of u64
These facilities can either be used inside functions on dynamic data:
int do_something(long q)
{
...;
y = ilog2(x)
...;
}
Or can be used to statically initialise global variables with constant values:
unsigned n = ilog2(27);
When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant. They treat negative numbers as
unsigned.
When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.
[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/infiniband/ulp')
| -rw-r--r-- | drivers/infiniband/ulp/iser/iser_memory.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c index 5e122501fd8..3aedd59b8a8 100644 --- a/drivers/infiniband/ulp/iser/iser_memory.c +++ b/drivers/infiniband/ulp/iser/iser_memory.c @@ -114,7 +114,7 @@ int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask, if (cmd_data_len > ISER_KMALLOC_THRESHOLD) mem = (void *)__get_free_pages(GFP_NOIO, - long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT); + ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT); else mem = kmalloc(cmd_data_len, GFP_NOIO); @@ -211,7 +211,7 @@ void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask, if (cmd_data_len > ISER_KMALLOC_THRESHOLD) free_pages((unsigned long)mem_copy->copy_buf, - long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT); + ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT); else kfree(mem_copy->copy_buf); |