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Commit b27eb186 authored by HATAYAMA Daisuke's avatar HATAYAMA Daisuke Committed by Linus Torvalds
Browse files

vmcore: clean up read_vmcore() 



Rewrite part of read_vmcore() that reads objects in vmcore_list in the
same way as part reading ELF headers, by which some duplicated and
redundant codes are removed.

Signed-off-by: default avatarHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0fa73b86

fs/proc/vmcore.c

+20 −48
Original line number Diff line number Diff line
@@ -118,27 +118,6 @@ static ssize_t read_from_oldmem(char *buf, size_t count, 
	return read;

}



/* Maps vmcore file offset to respective physical address in memroy. */

static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list,

					struct vmcore **m_ptr)

{

	struct vmcore *m;

	u64 paddr;



	list_for_each_entry(m, vc_list, list) {

		u64 start, end;

		start = m->offset;

		end = m->offset + m->size - 1;

		if (offset >= start && offset <= end) {

			paddr = m->paddr + offset - start;

			*m_ptr = m;

			return paddr;

		}

	}

	*m_ptr = NULL;

	return 0;

}



/* Read from the ELF header and then the crash dump. On error, negative value is

 * returned otherwise number of bytes read are returned.

 */
@@ -147,8 +126,8 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer, 
{

	ssize_t acc = 0, tmp;

	size_t tsz;

	u64 start, nr_bytes;

	struct vmcore *curr_m = NULL;

	u64 start;

	struct vmcore *m = NULL;



	if (buflen == 0 || *fpos >= vmcore_size)

		return 0;
@@ -174,18 +153,12 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer, 
			return acc;

	}



	start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);

	if (!curr_m)

        	return -EINVAL;



	while (buflen) {

		tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK));



		/* Calculate left bytes in current memory segment. */

		nr_bytes = (curr_m->size - (start - curr_m->paddr));

		if (tsz > nr_bytes)

			tsz = nr_bytes;



	list_for_each_entry(m, &vmcore_list, list) {

		if (*fpos < m->offset + m->size) {

			tsz = m->offset + m->size - *fpos;

			if (buflen < tsz)

				tsz = buflen;

			start = m->paddr + *fpos - m->offset;

			tmp = read_from_oldmem(buffer, tsz, &start, 1);

			if (tmp < 0)

				return tmp;
@@ -193,14 +166,13 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer, 
			*fpos += tsz;

			buffer += tsz;

			acc += tsz;

		if (start >= (curr_m->paddr + curr_m->size)) {

			if (curr_m->list.next == &vmcore_list)

				return acc;	/*EOF*/

			curr_m = list_entry(curr_m->list.next,

						struct vmcore, list);

			start = curr_m->paddr;



			/* leave now if filled buffer already */

			if (buflen == 0)

				return acc;

		}

	}



	return acc;

}