Mark Lord wrote:
...
And, yes, I make that out as being this line from blk_rq_map_sg():
next_sg = sg_next(sg);
"objdump -d" output from my actual kernel:
00003ce0 <blk_rq_map_sg>:
3ce0: 55 push %ebp
3ce1: 57 push %edi
3ce2: 56 push %esi
3ce3: 53 push %ebx
3ce4: 83 ec 24 sub $0x24,%esp
3ce7: 89 44 24 04 mov %eax,0x4(%esp)
3ceb: 8b 98 44 01 00 00 mov 0x144(%eax),%ebx
3cf1: 83 e3 01 and $0x1,%ebx
3cf4: 89 5c 24 14 mov %ebx,0x14(%esp)
3cf8: 8b 52 34 mov 0x34(%edx),%edx
3cfb: c7 44 24 10 00 00 00 movl $0x0,0x10(%esp)
3d02: 00
3d03: 85 d2 test %edx,%edx
3d05: 89 54 24 1c mov %edx,0x1c(%esp)
3d09: 0f 84 f4 00 00 00 je 3e03 <blk_rq_map_sg+0x123>
3d0f: 89 cb mov %ecx,%ebx
3d11: 31 ff xor %edi,%edi
3d13: 89 4c 24 0c mov %ecx,0xc(%esp)
3d17: 8b 44 24 1c mov 0x1c(%esp),%eax
3d1b: 0f b7 48 16 movzwl 0x16(%eax),%ecx
3d1f: 8b 50 2c mov 0x2c(%eax),%edx
3d22: 89 4c 24 18 mov %ecx,0x18(%esp)
3d26: 0f b7 40 14 movzwl 0x14(%eax),%eax
3d2a: 39 c1 cmp %eax,%ecx
3d2c: 0f 8d be 00 00 00 jge 3df0 <blk_rq_map_sg+0x110>
3d32: 8d 04 49 lea (%ecx,%ecx,2),%eax
3d35: 8d 34 82 lea (%edx,%eax,4),%esi
3d38: 0f b6 44 24 14 movzbl 0x14(%esp),%eax
3d3d: 88 44 24 23 mov %al,0x23(%esp)
3d41: eb 05 jmp 3d48 <blk_rq_map_sg+0x68>
3d43: 89 f7 mov %esi,%edi
3d45: 83 c6 0c add $0xc,%esi
3d48: 80 7c 24 23 00 cmpb $0x0,0x23(%esp)
3d4d: 8b 6e 04 mov 0x4(%esi),%ebp
3d50: 74 4e je 3da0 <blk_rq_map_sg+0xc0>
3d52: 85 ff test %edi,%edi
3d54: 74 4a je 3da0 <blk_rq_map_sg+0xc0>
3d56: 8b 54 24 0c mov 0xc(%esp),%edx
3d5a: 8b 44 24 04 mov 0x4(%esp),%eax
3d5e: 8b 4a 0c mov 0xc(%edx),%ecx
3d61: 01 e9 add %ebp,%ecx
3d63: 89 4c 24 08 mov %ecx,0x8(%esp)
3d67: 3b 88 94 01 00 00 cmp 0x194(%eax),%ecx
3d6d: 77 31 ja 3da0 <blk_rq_map_sg+0xc0>
3d6f: 8b 15 00 00 00 00 mov 0x0,%edx
3d75: 8b 0f mov (%edi),%ecx
3d77: 8b 47 04 mov 0x4(%edi),%eax
3d7a: 29 d1 sub %edx,%ecx
3d7c: c1 f9 05 sar $0x5,%ecx
3d7f: c1 e1 0c shl $0xc,%ecx
3d82: 03 4f 08 add 0x8(%edi),%ecx
3d85: 8d 3c 01 lea (%ecx,%eax,1),%edi
3d88: 8b 06 mov (%esi),%eax
3d8a: 29 d0 sub %edx,%eax
3d8c: c1 f8 05 sar $0x5,%eax
3d8f: c1 e0 0c shl $0xc,%eax
3d92: 03 46 08 add 0x8(%esi),%eax
3d95: 39 c7 cmp %eax,%edi
3d97: 74 76 je 3e0f <blk_rq_map_sg+0x12f>
3d99: 8d b4 26 00 00 00 00 lea 0x0(%esi),%esi
3da0: 8d 43 10 lea 0x10(%ebx),%eax
3da3: b9 04 00 00 00 mov $0x4,%ecx
3da8: 89 04 24 mov %eax,(%esp)
3dab: 8b 43 10 mov 0x10(%ebx),%eax <<<<--------- dies here
3dae: 89 df mov %ebx,%edi
3db0: 89 c2 mov %eax,%edx
3db2: 83 e2 fe and $0xfffffffe,%edx
3db5: a8 01 test $0x1,%al
3db7: 0f 44 14 24 cmove (%esp),%edx
3dbb: 31 c0 xor %eax,%eax
3dbd: f3 ab rep stos %eax,%es:(%edi)
3dbf: 8b 06 mov (%esi),%eax
3dc1: 89 6b 0c mov %ebp,0xc(%ebx)
3dc4: 89 03 mov %eax,(%ebx)
3dc6: 8b 46 08 mov 0x8(%esi),%eax
3dc9: 89 43 04 mov %eax,0x4(%ebx)
3dcc: 83 44 24 10 01 addl $0x1,0x10(%esp)
3dd1: 89 5c 24 0c mov %ebx,0xc(%esp)
3dd5: 89 d3 mov %edx,%ebx
3dd7: 8b 54 24 1c mov 0x1c(%esp),%edx
-
