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Message-ID: <20250305152555.318159-2-ryasuoka@redhat.com>
Date: Thu, 6 Mar 2025 00:25:53 +0900
From: Ryosuke Yasuoka <ryasuoka@...hat.com>
To: maarten.lankhorst@...ux.intel.com,
mripard@...nel.org,
tzimmermann@...e.de,
airlied@...il.com,
simona@...ll.ch,
kraxel@...hat.com,
gurchetansingh@...omium.org,
olvaffe@...il.com,
akpm@...ux-foundation.org,
urezki@...il.com,
hch@...radead.org,
dmitry.osipenko@...labora.com,
jfalempe@...hat.com
Cc: Ryosuke Yasuoka <ryasuoka@...hat.com>,
dri-devel@...ts.freedesktop.org,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux.dev,
linux-mm@...ck.org
Subject: [PATCH drm-next 1/2] vmalloc: Add atomic_vmap
Some drivers can use vmap in drm_panic, however, vmap is sleepable and
takes locks. Since drm_panic will vmap in panic handler, atomic_vmap
requests pages with GFP_ATOMIC and maps KVA without locks and sleep.
Signed-off-by: Ryosuke Yasuoka <ryasuoka@...hat.com>
---
include/linux/vmalloc.h | 2 +
mm/internal.h | 5 ++
mm/vmalloc.c | 105 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 112 insertions(+)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 31e9ffd936e3..c7a2a9a1976d 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -190,6 +190,8 @@ void * __must_check vrealloc_noprof(const void *p, size_t size, gfp_t flags)
extern void vfree(const void *addr);
extern void vfree_atomic(const void *addr);
+extern void *atomic_vmap(struct page **pages, unsigned int count,
+ unsigned long flags, pgprot_t prot);
extern void *vmap(struct page **pages, unsigned int count,
unsigned long flags, pgprot_t prot);
void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot);
diff --git a/mm/internal.h b/mm/internal.h
index 109ef30fee11..134b332bf5b9 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1278,6 +1278,11 @@ int numa_migrate_check(struct folio *folio, struct vm_fault *vmf,
void free_zone_device_folio(struct folio *folio);
int migrate_device_coherent_folio(struct folio *folio);
+struct vm_struct *atomic_get_vm_area_node(unsigned long size, unsigned long align,
+ unsigned long shift, unsigned long flags,
+ unsigned long start, unsigned long end, int node,
+ gfp_t gfp_mask, const void *caller);
+
struct vm_struct *__get_vm_area_node(unsigned long size,
unsigned long align, unsigned long shift,
unsigned long flags, unsigned long start,
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a6e7acebe9ad..f5c93779c60a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1945,6 +1945,57 @@ static inline void setup_vmalloc_vm(struct vm_struct *vm,
va->vm = vm;
}
+static struct vmap_area *atomic_alloc_vmap_area(unsigned long size,
+ unsigned long align,
+ unsigned long vstart, unsigned long vend,
+ int node, gfp_t gfp_mask,
+ unsigned long va_flags, struct vm_struct *vm)
+{
+ struct vmap_node *vn;
+ struct vmap_area *va;
+ unsigned long addr;
+
+ if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
+ return ERR_PTR(-EINVAL);
+
+ if (unlikely(!vmap_initialized))
+ return ERR_PTR(-EBUSY);
+
+ va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
+ if (unlikely(!va))
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * Only scan the relevant parts containing pointers to other objects
+ * to avoid false negatives.
+ */
+ kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask);
+
+ addr = __alloc_vmap_area(&free_vmap_area_root, &free_vmap_area_list,
+ size, align, vstart, vend);
+
+ trace_alloc_vmap_area(addr, size, align, vstart, vend, addr == vend);
+
+ va->va_start = addr;
+ va->va_end = addr + size;
+ va->vm = NULL;
+ va->flags = va_flags;
+
+ vm->addr = (void *)va->va_start;
+ vm->size = va_size(va);
+ va->vm = vm;
+
+ vn = addr_to_node(va->va_start);
+
+ insert_vmap_area(va, &vn->busy.root, &vn->busy.head);
+
+ BUG_ON(!IS_ALIGNED(va->va_start, align));
+ BUG_ON(va->va_start < vstart);
+ BUG_ON(va->va_end > vend);
+
+ return va;
+}
+
/*
* Allocate a region of KVA of the specified size and alignment, within the
* vstart and vend. If vm is passed in, the two will also be bound.
@@ -3106,6 +3157,33 @@ static void clear_vm_uninitialized_flag(struct vm_struct *vm)
vm->flags &= ~VM_UNINITIALIZED;
}
+struct vm_struct *atomic_get_vm_area_node(unsigned long size, unsigned long align,
+ unsigned long shift, unsigned long flags,
+ unsigned long start, unsigned long end, int node,
+ gfp_t gfp_mask, const void *caller)
+{
+ struct vmap_area *va;
+ struct vm_struct *area;
+
+ size = ALIGN(size, 1ul << shift);
+ if (unlikely(!size))
+ return NULL;
+
+ area = kzalloc_node(sizeof(*area), gfp_mask, node);
+ if (unlikely(!area))
+ return NULL;
+
+ size += PAGE_SIZE;
+ area->flags = flags;
+ area->caller = caller;
+
+ va = atomic_alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area);
+ if (IS_ERR(va))
+ return NULL;
+
+ return area;
+}
+
struct vm_struct *__get_vm_area_node(unsigned long size,
unsigned long align, unsigned long shift, unsigned long flags,
unsigned long start, unsigned long end, int node,
@@ -3418,6 +3496,33 @@ void vunmap(const void *addr)
}
EXPORT_SYMBOL(vunmap);
+void *atomic_vmap(struct page **pages, unsigned int count,
+ unsigned long flags, pgprot_t prot)
+{
+ struct vm_struct *area;
+ unsigned long addr;
+ unsigned long size; /* In bytes */
+
+ if (count > totalram_pages())
+ return NULL;
+
+ size = (unsigned long)count << PAGE_SHIFT;
+ area = atomic_get_vm_area_node(size, 1, PAGE_SHIFT, flags,
+ VMALLOC_START, VMALLOC_END,
+ NUMA_NO_NODE, GFP_ATOMIC,
+ __builtin_return_address(0));
+ if (!area)
+ return NULL;
+
+ addr = (unsigned long)area->addr;
+ if (vmap_pages_range(addr, addr + size, pgprot_nx(prot),
+ pages, PAGE_SHIFT) < 0) {
+ return NULL;
+ }
+
+ return area->addr;
+}
+
/**
* vmap - map an array of pages into virtually contiguous space
* @pages: array of page pointers
--
2.48.1
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