vmcore: clean up read_vmcore() (b27eb186) · Commits · 戴 / test

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;
		}

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