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/dev/mem: introduce size_inside_page()
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@intel.com> Acked-by: Andi Kleen <ak@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Avi Kivity <avi@qumranet.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4ea2f43f28
commit
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1 changed files with 19 additions and 41 deletions
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@ -34,6 +34,19 @@
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# include <linux/efi.h>
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#endif
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static inline unsigned long size_inside_page(unsigned long start,
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unsigned long size)
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{
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unsigned long sz;
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if (-start & (PAGE_SIZE - 1))
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sz = -start & (PAGE_SIZE - 1);
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else
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sz = PAGE_SIZE;
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return min_t(unsigned long, sz, size);
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}
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/*
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* Architectures vary in how they handle caching for addresses
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* outside of main memory.
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@ -141,15 +154,7 @@ static ssize_t read_mem(struct file * file, char __user * buf,
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#endif
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while (count > 0) {
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/*
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* Handle first page in case it's not aligned
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*/
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if (-p & (PAGE_SIZE - 1))
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sz = -p & (PAGE_SIZE - 1);
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else
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sz = PAGE_SIZE;
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sz = min_t(unsigned long, sz, count);
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sz = size_inside_page(p, count);
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if (!range_is_allowed(p >> PAGE_SHIFT, count))
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return -EPERM;
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@ -208,15 +213,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
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#endif
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while (count > 0) {
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/*
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* Handle first page in case it's not aligned
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*/
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if (-p & (PAGE_SIZE - 1))
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sz = -p & (PAGE_SIZE - 1);
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else
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sz = PAGE_SIZE;
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sz = min_t(unsigned long, sz, count);
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sz = size_inside_page(p, count);
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if (!range_is_allowed(p >> PAGE_SHIFT, sz))
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return -EPERM;
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@ -429,15 +426,7 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
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}
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#endif
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while (low_count > 0) {
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/*
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* Handle first page in case it's not aligned
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*/
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if (-p & (PAGE_SIZE - 1))
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sz = -p & (PAGE_SIZE - 1);
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else
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sz = PAGE_SIZE;
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sz = min_t(unsigned long, sz, low_count);
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sz = size_inside_page(p, low_count);
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/*
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* On ia64 if a page has been mapped somewhere as
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@ -461,10 +450,8 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
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if (!kbuf)
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return -ENOMEM;
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while (count > 0) {
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int len = count;
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int len = size_inside_page(p, count);
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if (len > PAGE_SIZE)
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len = PAGE_SIZE;
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len = vread(kbuf, (char *)p, len);
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if (!len)
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break;
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@ -509,15 +496,8 @@ do_write_kmem(void *p, unsigned long realp, const char __user * buf,
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while (count > 0) {
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char *ptr;
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/*
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* Handle first page in case it's not aligned
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*/
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if (-realp & (PAGE_SIZE - 1))
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sz = -realp & (PAGE_SIZE - 1);
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else
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sz = PAGE_SIZE;
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sz = min_t(unsigned long, sz, count);
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sz = size_inside_page(realp, count);
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/*
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* On ia64 if a page has been mapped somewhere as
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@ -577,10 +557,8 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
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if (!kbuf)
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return wrote ? wrote : -ENOMEM;
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while (count > 0) {
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int len = count;
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int len = size_inside_page(p, count);
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if (len > PAGE_SIZE)
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len = PAGE_SIZE;
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written = copy_from_user(kbuf, buf, len);
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if (written) {
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if (wrote + virtr)
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