On Wed, 30 Oct 2013 10:18:21 +0000 James Hogan <james.hogan@xxxxxxxxxx> wrote: > Commit 3e39c1ab04ba (printk: mark printk_once test variable > __read_mostly) added __read_mostly to the __print_once bool in the > printk_once() macro, but __read_mostly is defined in <linux/cache.h> > which isn't included from <linux/printk.h>. This results in build errors > like this: > > arch/metag/mm/l2cache.c: In function 'meta_l2c_setup': > arch/metag/mm/l2cache.c:56: error: '__read_mostly' undeclared > > This is fixed by adding an include of <linux/cache.h> from > <linux/printk.h> since I don't think printk_once() users should need to > include <linux/cache.h> for it to work. > > Note that this actually adds a recursive include, since <linux/cache.h> > includes <linux/kernel.h>, which includes <linux/printk.h>. The actual > dependencies are all in macros so it doesn't actually seem to result in > any build failures, but it's clearly less than ideal. Yitch. > Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx> > Cc: Joe Perches <joe@xxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: linux-metag@xxxxxxxxxxxxxxx > --- > This build failure was caught in today's linux-next. > > I'm not too keen on this due to the recursive include. Is it better to > just workaround the problem by including <linux/cache.h> from the .c > file that fails to build, or should the original patch be removed > instead? Well, these patches make the kernel worse. We should make it better, not worse. One approach would be to add a new printk_once.h, which includes printk.h and cache.h. I can't immediately think of a nice solution so I guess for now I'll drop printk-mark-printk_once-test-variable-__read_mostly.patch. -- To unsubscribe from this list: send the line "unsubscribe linux-metag" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
