RDMA/core: Fix ib_dma_max_seg_size()
If dev->dma_device->params == NULL then the maximum DMA segment size is 64
KB. See also the dma_get_max_seg_size() implementation. This patch fixes
the following kernel warning:
DMA-API: infiniband rxe0: mapping sg segment longer than device claims to support [len=126976] [max=65536]
WARNING: CPU: 4 PID: 4848 at kernel/dma/debug.c:1220 debug_dma_map_sg+0x3d9/0x450
RIP: 0010:debug_dma_map_sg+0x3d9/0x450
Call Trace:
srp_queuecommand+0x626/0x18d0 [ib_srp]
scsi_queue_rq+0xd02/0x13e0 [scsi_mod]
__blk_mq_try_issue_directly+0x2b3/0x3f0
blk_mq_request_issue_directly+0xac/0xf0
blk_insert_cloned_request+0xdf/0x170
dm_mq_queue_rq+0x43d/0x830 [dm_mod]
__blk_mq_try_issue_directly+0x2b3/0x3f0
blk_mq_request_issue_directly+0xac/0xf0
blk_mq_try_issue_list_directly+0xb8/0x170
blk_mq_sched_insert_requests+0x23c/0x3b0
blk_mq_flush_plug_list+0x529/0x730
blk_flush_plug_list+0x21f/0x260
blk_mq_make_request+0x56b/0xf20
generic_make_request+0x196/0x660
submit_bio+0xae/0x290
blkdev_direct_IO+0x822/0x900
generic_file_direct_write+0x110/0x200
__generic_file_write_iter+0x124/0x2a0
blkdev_write_iter+0x168/0x270
aio_write+0x1c4/0x310
io_submit_one+0x971/0x1390
__x64_sys_io_submit+0x12a/0x390
do_syscall_64+0x6f/0x2e0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Link: https://lore.kernel.org/r/20191025225830.257535-2-bvanassche@acm.org
Cc: <stable@vger.kernel.org>
Fixes: 0b5cb3300a ("RDMA/srp: Increase max_segment_size")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
ecdfdfdbe4