On Wed, Dec 22, 2021 at 05:37:07PM +0800, Baoquan He wrote: > > /* allocate transfer buffer */ > > - buffer = kmalloc(512, GFP_KERNEL | GFP_DMA); > > + buffer = kmalloc(512, GFP_KERNEL); > > Thanks a lot for doing this. When I browsed the code path, I come to > blk_rq_map_kern() but I am not sure if blk_queue_may_bounce() is true in > the sr_probe() case, then it may enter into bio_map_kern(). blk_queue_may_bounce will be entered for the few drives that set BLK_BOUNCE_HIGH because they can't handle highmem (which is a subset of the non-ZONE_DMA memory). The only driver that actually requires ZONE_DMA based bouncing is ps3rom, and that driver does a manual and ubconditional bounce buffering. > Next I will post my original patchset to mute the allocation failure if > it's requesting page from DMA zone and DMA zone has no managed page. And > meanwhile, I will try to collect those places of kmalloc(GFP_DMA) into a > RFC mail, see if we can change them one by one. Anyone can pick one > place to fix if interested or knowing it well. I've already sent out patches for all of drivers/scsi/ today, except for the ps3rom bounce buffer alllocation which is fine but should probably be changed to use the page allocator directly. > Finally, we can remove the > need of dma-kmalloc() as people suggested. Any comment? Yes.
