Hello Zhi Wang,
The patch 2707e4446688: "drm/i915/gvt: vGPU graphics memory virtualization" from Mar 28, 2016, leads to the following static checker warnings:
drivers/gpu/drm/i915/gvt/gtt.c:1675 intel_vgpu_pin_mm() warn: 'mm->pincount.counter' not decremented on lines: 1670,1675.
drivers/gpu/drm/i915/gvt/gtt.c:1932 intel_gvt_create_scratch_page() warn: signedness bug returning '(-12)'
drivers/gpu/drm/i915/gvt/gtt.c 1647 /** 1648 * intel_vgpu_pin_mm - increase the pin count of a vGPU mm object 1649 * @vgpu: a vGPU 1650 * 1651 * This function is called when user wants to use a vGPU mm object. If this 1652 * mm object hasn't been shadowed yet, the shadow will be populated at this 1653 * time. 1654 * 1655 * Returns: 1656 * Zero on success, negative error code if failed. 1657 */ 1658 int intel_vgpu_pin_mm(struct intel_vgpu_mm *mm) 1659 { 1660 int ret; 1661 1662 if (WARN_ON(mm->type != INTEL_GVT_MM_PPGTT)) 1663 return 0;
Should this be "return -EINVAL;"?
1664 1665 atomic_inc(&mm->pincount); 1666 1667 if (!mm->shadowed) { 1668 ret = shadow_mm(mm); 1669 if (ret) 1670 return ret;
Should we decrement ->pincount before we return? Or perhaps in invalidate_mm()?
1671 } 1672 1673 list_del_init(&mm->lru_list); 1674 list_add_tail(&mm->lru_list, &mm->vgpu->gvt->gtt.mm_lru_list_head); 1675 return 0; 1676 }
[ snip ]
1922 bool intel_gvt_create_scratch_page(struct intel_vgpu *vgpu) ^^^^ 1923 { 1924 struct intel_vgpu_gtt *gtt = &vgpu->gtt; 1925 void *p; 1926 void *vaddr; 1927 unsigned long mfn; 1928 1929 gtt->scratch_page = alloc_page(GFP_KERNEL); 1930 if (!gtt->scratch_page) { 1931 gvt_err("Failed to allocate scratch page.\n"); 1932 return -ENOMEM; ^^^^^^^^^^^^^^^ This means return true.
1933 } 1934 1935 /* set to zero */ 1936 p = kmap_atomic(gtt->scratch_page); 1937 memset(p, 0, PAGE_SIZE); 1938 kunmap_atomic(p); 1939 1940 /* translate page to mfn */ 1941 vaddr = page_address(gtt->scratch_page); 1942 mfn = intel_gvt_hypervisor_virt_to_mfn(vaddr); 1943 1944 if (mfn == INTEL_GVT_INVALID_ADDR) { 1945 gvt_err("fail to translate vaddr:0x%llx\n", (u64)vaddr); 1946 __free_page(gtt->scratch_page); 1947 gtt->scratch_page = NULL; 1948 return -ENXIO; ^^^^^^^^^^^^^ Same. The caller doesn't care. Maybe make this a void function?
1949 } 1950 1951 gtt->scratch_page_mfn = mfn; 1952 gvt_dbg_core("vgpu%d create scratch page: mfn=0x%lx\n", vgpu->id, mfn); 1953 return 0; 1954 }
regards, dan carpenter