I can't come up with a satisfying reason why we still need the memory
segment list. We used to represent in the list:
- boot memory
- standby memory added via add_memory()
- loaded dcss segments
When loading/unloading dcss segments, we already track them in a
separate list and check for overlaps
(arch/s390/mm/extmem.c:segment_overlaps_others()) when loading segments.
The overlap check was introduced for some segments in
commit b2300b9efe1b ("[S390] dcssblk: add >2G DCSSs support and stacked
contiguous DCSSs support.")
and was extended to cover all dcss segments in
commit ca57114609d1 ("s390/extmem: remove code for 31 bit addressing
mode").
Although I doubt that overlaps with boot memory and standby memory
are relevant, let's reshuffle the checks in load_segment() to request
the resource first. This will bail out in case we have overlaps with
other resources (esp. boot memory and standby memory). The order
is now different compared to segment_unload() and segment_unload(), but
that should not matter.
This smells like a leftover from ancient times, let's get rid of it. We
can now convert vmem_remove_mapping() into a void function - everybody
ignored the return value already.
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
arch/s390/include/asm/pgtable.h | 2 +-
arch/s390/mm/extmem.c | 25 +++----
arch/s390/mm/vmem.c | 115 ++------------------------------
3 files changed, 21 insertions(+), 121 deletions(-)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 19d603bd1f36e..7eb01a5459cdf 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1669,7 +1669,7 @@ static inline swp_entry_t __swp_entry(unsigned long type, unsigned long offset)
#define kern_addr_valid(addr) (1)
extern int vmem_add_mapping(unsigned long start, unsigned long size);
-extern int vmem_remove_mapping(unsigned long start, unsigned long size);
+extern void vmem_remove_mapping(unsigned long start, unsigned long size);
extern int s390_enable_sie(void);
extern int s390_enable_skey(void);
extern void s390_reset_cmma(struct mm_struct *mm);
diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
index 9e0aa7aa03ba4..105c09282f8c5 100644
--- a/arch/s390/mm/extmem.c
+++ b/arch/s390/mm/extmem.c
@@ -313,15 +313,10 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
goto out_free;
}
- rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
-
- if (rc)
- goto out_free;
-
seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
if (seg->res == NULL) {
rc = -ENOMEM;
- goto out_shared;
+ goto out_free;
}
seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
seg->res->start = seg->start_addr;
@@ -335,12 +330,17 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
if (rc == SEG_TYPE_SC ||
((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
seg->res->flags |= IORESOURCE_READONLY;
+
+ /* Check for overlapping resources before adding the mapping. */
if (request_resource(&iomem_resource, seg->res)) {
rc = -EBUSY;
- kfree(seg->res);
- goto out_shared;
+ goto out_free_resource;
}
+ rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+ if (rc)
+ goto out_resource;
+
if (do_nonshared)
diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
&start_addr, &end_addr);
@@ -351,14 +351,14 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
dcss_diag(&purgeseg_scode, seg->dcss_name,
&dummy, &dummy);
rc = diag_cc;
- goto out_resource;
+ goto out_mapping;
}
if (diag_cc > 1) {
pr_warn("Loading DCSS %s failed with rc=%ld\n", name, end_addr);
rc = dcss_diag_translate_rc(end_addr);
dcss_diag(&purgeseg_scode, seg->dcss_name,
&dummy, &dummy);
- goto out_resource;
+ goto out_mapping;
}
seg->start_addr = start_addr;
seg->end = end_addr;
@@ -377,11 +377,12 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
(void*) seg->end, segtype_string[seg->vm_segtype]);
}
goto out;
+ out_mapping:
+ vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
out_resource:
release_resource(seg->res);
+ out_free_resource:
kfree(seg->res);
- out_shared:
- vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
out_free:
kfree(seg);
out:
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 8b6282cf7d139..3b9e71654c37b 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -20,14 +20,6 @@
static DEFINE_MUTEX(vmem_mutex);
-struct memory_segment {
- struct list_head list;
- unsigned long start;
- unsigned long size;
-};
-
-static LIST_HEAD(mem_segs);
-
static void __ref *vmem_alloc_pages(unsigned int order)
{
unsigned long size = PAGE_SIZE << order;
@@ -300,94 +292,25 @@ void vmemmap_free(unsigned long start, unsigned long end,
{
}
-/*
- * Add memory segment to the segment list if it doesn't overlap with
- * an already present segment.
- */
-static int insert_memory_segment(struct memory_segment *seg)
-{
- struct memory_segment *tmp;
-
- if (seg->start + seg->size > VMEM_MAX_PHYS ||
- seg->start + seg->size < seg->start)
- return -ERANGE;
-
- list_for_each_entry(tmp, &mem_segs, list) {
- if (seg->start >= tmp->start + tmp->size)
- continue;
- if (seg->start + seg->size <= tmp->start)
- continue;
- return -ENOSPC;
- }
- list_add(&seg->list, &mem_segs);
- return 0;
-}
-
-/*
- * Remove memory segment from the segment list.
- */
-static void remove_memory_segment(struct memory_segment *seg)
-{
- list_del(&seg->list);
-}
-
-static void __remove_shared_memory(struct memory_segment *seg)
+void vmem_remove_mapping(unsigned long start, unsigned long size)
{
- remove_memory_segment(seg);
- vmem_remove_range(seg->start, seg->size);
-}
-
-int vmem_remove_mapping(unsigned long start, unsigned long size)
-{
- struct memory_segment *seg;
- int ret;
-
mutex_lock(&vmem_mutex);
-
- ret = -ENOENT;
- list_for_each_entry(seg, &mem_segs, list) {
- if (seg->start == start && seg->size == size)
- break;
- }
-
- if (seg->start != start || seg->size != size)
- goto out;
-
- ret = 0;
- __remove_shared_memory(seg);
- kfree(seg);
-out:
+ vmem_remove_range(start, size);
mutex_unlock(&vmem_mutex);
- return ret;
}
int vmem_add_mapping(unsigned long start, unsigned long size)
{
- struct memory_segment *seg;
int ret;
- mutex_lock(&vmem_mutex);
- ret = -ENOMEM;
- seg = kzalloc(sizeof(*seg), GFP_KERNEL);
- if (!seg)
- goto out;
- seg->start = start;
- seg->size = size;
-
- ret = insert_memory_segment(seg);
- if (ret)
- goto out_free;
+ if (start + size > VMEM_MAX_PHYS ||
+ start + size < start)
+ return -ERANGE;
+ mutex_lock(&vmem_mutex);
ret = vmem_add_mem(start, size);
if (ret)
- goto out_remove;
- goto out;
-
-out_remove:
- __remove_shared_memory(seg);
-out_free:
- kfree(seg);
-out:
+ vmem_remove_range(start, size);
mutex_unlock(&vmem_mutex);
return ret;
}
@@ -421,27 +344,3 @@ void __init vmem_map_init(void)
pr_info("Write protected kernel read-only data: %luk\n",
(unsigned long)(__end_rodata - _stext) >> 10);
}
-
-/*
- * Convert memblock.memory to a memory segment list so there is a single
- * list that contains all memory segments.
- */
-static int __init vmem_convert_memory_chunk(void)
-{
- struct memblock_region *reg;
- struct memory_segment *seg;
-
- mutex_lock(&vmem_mutex);
- for_each_memblock(memory, reg) {
- seg = kzalloc(sizeof(*seg), GFP_KERNEL);
- if (!seg)
- panic("Out of memory...\n");
- seg->start = reg->base;
- seg->size = reg->size;
- insert_memory_segment(seg);
- }
- mutex_unlock(&vmem_mutex);
- return 0;
-}
-
-core_initcall(vmem_convert_memory_chunk);
--
2.26.2
