Subject: + mm-mempool-warn-about-__gfp_zero-usage.patch added to -mm tree To: sebott@xxxxxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 16 Apr 2014 14:23:09 -0700 The patch titled Subject: mm/mempool: warn about __GFP_ZERO usage has been added to the -mm tree. Its filename is mm-mempool-warn-about-__gfp_zero-usage.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-mempool-warn-about-__gfp_zero-usage.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-mempool-warn-about-__gfp_zero-usage.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx> Subject: mm/mempool: warn about __GFP_ZERO usage Memory obtained via mempool_alloc is not always zeroed even when called with __GFP_ZERO. Add a note and VM_BUG_ON statement to make that clear. Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mempool.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN mm/mempool.c~mm-mempool-warn-about-__gfp_zero-usage mm/mempool.c --- a/mm/mempool.c~mm-mempool-warn-about-__gfp_zero-usage +++ a/mm/mempool.c @@ -192,6 +192,7 @@ EXPORT_SYMBOL(mempool_resize); * returns NULL. Note that due to preallocation, this function * *never* fails when called from process contexts. (it might * fail if called from an IRQ context.) + * Note: using __GFP_ZERO is not supported. */ void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask) { @@ -200,6 +201,7 @@ void * mempool_alloc(mempool_t *pool, gf wait_queue_t wait; gfp_t gfp_temp; + VM_BUG_ON(gfp_mask & __GFP_ZERO); might_sleep_if(gfp_mask & __GFP_WAIT); gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ _ Patches currently in -mm which might be from sebott@xxxxxxxxxxxxxxxxxx are include-linux-mmdebugh-add-vm_warn_on-and-vm_warn_on_once.patch mm-mempool-warn-about-__gfp_zero-usage.patch mm-mempool-warn-about-__gfp_zero-usage-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html