On 02/10/17 17:09, Linus Walleij wrote: > On Sun, Oct 1, 2017 at 12:57 PM, Tetsuo Handa > <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote: > >>>> I inserted u-SD card, only to realize that it is not detected as it >>>> should be. And dmesg indeed reveals: >>> >>> Tetsuo asked me to report this to linux-mm. >>> >>> But 2^4 is 16 pages, IIRC that can't be expected to work reliably, and >>> thus this sounds like MMC bug, not mm bug. > > > I'm not sure I fully understand this error message: > "worker/2:1: page allocation failure: order:4" > > What I guess from context is that the mmc_init_request() > call is failing to allocate 16 pages, meaning for 4K pages > 64KB which is the typical bounce buffer. > > This is what the code has always allocated as bounce buffer, > but it used to happen upfront, when probing the MMC block layer, > rather than when allocating the requests. That is not exactly right. As I already wrote, the memory allocation used to be optional but became mandatory with: commit 304419d8a7e9204c5d19b704467b814df8c8f5b1 Author: Linus Walleij <linus.walleij@xxxxxxxxxx> Date: Thu May 18 11:29:32 2017 +0200 mmc: core: Allocate per-request data using the block layer core -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html