On Mon, Feb 17, 2014 at 10:11:51PM +0100, Geert Uytterhoeven wrote:

On Mon, Feb 17, 2014 at 10:06 PM, Randy Dunlap [off-list ref] wrote:

quoted

On 02/17/2014 01:00 PM, Geert Uytterhoeven wrote:

quoted

On Fri, Feb 14, 2014 at 8:04 PM, Linux Kernel Mailing List
[off-list ref] wrote:

quoted

   bcache: Minor fixes from kbuild robot

quoted

diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 4f6b594..3f74b4b 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c

@@ -23,7 +23,7 @@ void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned set)
        for (k = i->start; k < bset_bkey_last(i); k = next) {
                next = bkey_next(k);

-               printk(KERN_ERR "block %u key %zi/%u: ", set,
+               printk(KERN_ERR "block %u key %li/%u: ", set,
                       (uint64_t *) k - i->d, i->keys);

                if (b->ops->key_dump)

On 32-bit (m68k):
drivers/md/bcache/bset.c: In function ‘bch_dump_bset’:
drivers/md/bcache/bset.c:27: warning: format ‘%li’ expects type ‘long
int’, but argument 3 has type ‘int’

What are you trying to print here? It looks a bit strange to me.
Technically, the difference between two pointers is of type ptrdiff_.
The kernel had

typedef __kernel_ptrdiff_t      ptrdiff_t;

and

#if __BITS_PER_LONG != 64
typedef unsigned int    __kernel_size_t;
typedef int             __kernel_ssize_t;
typedef int             __kernel_ptrdiff_t;
#else
typedef __kernel_ulong_t __kernel_size_t;
typedef __kernel_long_t __kernel_ssize_t;
typedef __kernel_long_t __kernel_ptrdiff_t;
#endif

So I'd expect "%zi" to be the right way, and a quick test compile on
32-bit (m68k)
and 64-bit (amd64) comfirms that. What was wrong with it?

The kernel supports 't' (%t) for ptrdiff_t (same as glibc),
so %ti should work (or %tu).

Yes, that compiles without warnings, too.

And after more decyphering, "(uint64_t *) k - i->d" seems to be positive,
so "%tu" should be OK.

*swears* Actually, I'm just going to cast this to unsigned (that's definitely
safe here):


commit 70bc49d421c793f73a772ae1f50622a39c6136d9
Author: Kent Overstreet [off-list ref]
Date:   Mon Feb 17 13:44:06 2014 -0800

    bcache: Fix another compiler warning on m68k
    
    Use a bigger hammer this time
    
    Signed-off-by: Kent Overstreet [off-list ref]

diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 3f74b4b074..5454164153 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c

@@ -23,8 +23,8 @@ void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned set)
 	for (k = i->start; k < bset_bkey_last(i); k = next) {
 		next = bkey_next(k);
 
-		printk(KERN_ERR "block %u key %li/%u: ", set,
-		       (uint64_t *) k - i->d, i->keys);
+		printk(KERN_ERR "block %u key %u/%u: ", set,
+		       (unsigned) ((u64 *) k - i->d), i->keys);
 
 		if (b->ops->key_dump)
 			b->ops->key_dump(b, k);