The patch titled
/dev/mem: introduce size_inside_page()
has been added to the -mm tree. Its filename is
dev-mem-introduce-size_inside_page.patch
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------------------------------------------------------
Subject: /dev/mem: introduce size_inside_page()
From: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Introduce size_inside_page() to replace duplicate /dev/mem code.
Also apply it to /dev/kmem, whose alignment logic was buggy.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Acked-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/mem.c | 60 +++++++++++++------------------------------
1 file changed, 19 insertions(+), 41 deletions(-)
diff -puN drivers/char/mem.c~dev-mem-introduce-size_inside_page drivers/char/mem.c
--- a/drivers/char/mem.c~dev-mem-introduce-size_inside_page
+++ a/drivers/char/mem.c
@@ -35,6 +35,19 @@
# include <linux/efi.h>
#endif
+static inline unsigned long size_inside_page(unsigned long start,
+ unsigned long size)
+{
+ unsigned long sz;
+
+ if (-start & (PAGE_SIZE - 1))
+ sz = -start & (PAGE_SIZE - 1);
+ else
+ sz = PAGE_SIZE;
+
+ return min_t(unsigned long, sz, size);
+}
+
/*
* Architectures vary in how they handle caching for addresses
* outside of main memory.
@@ -142,15 +155,7 @@ static ssize_t read_mem(struct file * fi
#endif
while (count > 0) {
- /*
- * Handle first page in case it's not aligned
- */
- if (-p & (PAGE_SIZE - 1))
- sz = -p & (PAGE_SIZE - 1);
- else
- sz = PAGE_SIZE;
-
- sz = min_t(unsigned long, sz, count);
+ sz = size_inside_page(p, count);
if (!range_is_allowed(p >> PAGE_SHIFT, count))
return -EPERM;
@@ -209,15 +214,7 @@ static ssize_t write_mem(struct file * f
#endif
while (count > 0) {
- /*
- * Handle first page in case it's not aligned
- */
- if (-p & (PAGE_SIZE - 1))
- sz = -p & (PAGE_SIZE - 1);
- else
- sz = PAGE_SIZE;
-
- sz = min_t(unsigned long, sz, count);
+ sz = size_inside_page(p, count);
if (!range_is_allowed(p >> PAGE_SHIFT, sz))
return -EPERM;
@@ -430,15 +427,7 @@ static ssize_t read_kmem(struct file *fi
}
#endif
while (low_count > 0) {
- /*
- * Handle first page in case it's not aligned
- */
- if (-p & (PAGE_SIZE - 1))
- sz = -p & (PAGE_SIZE - 1);
- else
- sz = PAGE_SIZE;
-
- sz = min_t(unsigned long, sz, low_count);
+ sz = size_inside_page(p, low_count);
/*
* On ia64 if a page has been mapped somewhere as
@@ -462,10 +451,8 @@ static ssize_t read_kmem(struct file *fi
if (!kbuf)
return -ENOMEM;
while (count > 0) {
- int len = count;
+ int len = size_inside_page(p, count);
- if (len > PAGE_SIZE)
- len = PAGE_SIZE;
len = vread(kbuf, (char *)p, len);
if (!len)
break;
@@ -510,15 +497,8 @@ do_write_kmem(void *p, unsigned long rea
while (count > 0) {
char *ptr;
- /*
- * Handle first page in case it's not aligned
- */
- if (-realp & (PAGE_SIZE - 1))
- sz = -realp & (PAGE_SIZE - 1);
- else
- sz = PAGE_SIZE;
- sz = min_t(unsigned long, sz, count);
+ sz = size_inside_page(realp, count);
/*
* On ia64 if a page has been mapped somewhere as
@@ -578,10 +558,8 @@ static ssize_t write_kmem(struct file *
if (!kbuf)
return wrote ? wrote : -ENOMEM;
while (count > 0) {
- int len = count;
+ int len = size_inside_page(p, count);
- if (len > PAGE_SIZE)
- len = PAGE_SIZE;
written = copy_from_user(kbuf, buf, len);
if (written) {
if (wrote + virtr)
_
Patches currently in -mm which might be from fengguang.wu@xxxxxxxxx are
linux-next.patch
mm-memory-failure-remove-config_unevictable_lru-config-option.patch
readahead-add-blk_run_backing_dev.patch
readahead-add-blk_run_backing_dev-fix.patch
readahead-add-blk_run_backing_dev-fix-fix-2.patch
mm-clean-up-page_remove_rmap.patch
mm-oom-analysis-add-per-zone-statistics-to-show_free_areas.patch
mm-oom-analysis-add-buffer-cache-information-to-show_free_areas.patch
mm-oom-analysis-add-shmem-vmstat.patch
mm-shrink_inactive_list-nr_scan-accounting-fix-fix.patch
mm-vmstat-add-isolate-pages.patch
mm-vmstat-add-isolate-pages-fix.patch
vmscan-throttle-direct-reclaim-when-too-many-pages-are-isolated-already.patch
mm-remove-__addsub_zone_page_state.patch
mm-count-only-reclaimable-lru-pages-v2.patch
vmscan-move-clearpageactive-from-move_active_pages-to-shrink_active_list.patch
vmscan-kill-unnecessary-page-flag-test.patch
vmscan-kill-unnecessary-prefetch.patch
ksm-add-mmu_notifier-set_pte_at_notify.patch
ksm-first-tidy-up-madvise_vma.patch
ksm-define-madv_mergeable-and-madv_unmergeable.patch
ksm-the-mm-interface-to-ksm.patch
ksm-no-debug-in-page_dup_rmap.patch
ksm-identify-pageksm-pages.patch
ksm-kernel-samepage-merging.patch
ksm-prevent-mremap-move-poisoning.patch
ksm-change-copyright-message.patch
ksm-change-ksm-nice-level-to-be-5.patch
mm-do-batched-scans-for-mem_cgroup.patch
mm-vsmcan-check-shrink_active_list-sc-isolate_pages-return-value.patch
dev-mem-remove-redundant-test-on-len.patch
dev-mem-introduce-size_inside_page.patch
dev-mem-cleanup-unxlate_dev_mem_ptr-calls.patch
dev-mem-cleanup-unxlate_dev_mem_ptr-calls-fix.patch
documentation-vm-gitignore-add-page-types.patch
page-types-add-feature-for-walking-process-address-space.patch
page-types-add-feature-for-walking-process-address-space-checkpatch-fixes.patch
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