x86/crashdump/32: Simplify copy_oldmem_page() (7e015a27) · Commits · 戴 / test

arch/x86/kernel/crash_dump_32.c

+10 −38

Original line number	Diff line number	Diff line
		@@ -13,8 +13,6 @@

		#include <linux/uaccess.h>

		static void *kdump_buf_page;

		static inline bool is_crashed_pfn_valid(unsigned long pfn)
		{
		#ifndef CONFIG_X86_PAE
		@@ -41,15 +39,11 @@ static inline bool is_crashed_pfn_valid(unsigned long pfn)
		* @userbuf: if set, @buf is in user address space, use copy_to_user(),
		* otherwise @buf is in kernel address space, use memcpy().
		*
		* Copy a page from "oldmem". For this page, there is no pte mapped
		* in the current kernel. We stitch up a pte, similar to kmap_atomic.
		*
		* Calling copy_to_user() in atomic context is not desirable. Hence first
		* copying the data to a pre-allocated kernel page and then copying to user
		* space in non-atomic context.
		* Copy a page from "oldmem". For this page, there might be no pte mapped
		* in the current kernel.
		*/
		ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
		size_t csize, unsigned long offset, int userbuf)
		ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
		unsigned long offset, int userbuf)
		{
		void *vaddr;

		@@ -59,38 +53,16 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
		if (!is_crashed_pfn_valid(pfn))
		return -EFAULT;

		vaddr = kmap_atomic_pfn(pfn);
		vaddr = kmap_local_pfn(pfn);

		if (!userbuf) {
		memcpy(buf, (vaddr + offset), csize);
		kunmap_atomic(vaddr);
		memcpy(buf, vaddr + offset, csize);
		} else {
		if (!kdump_buf_page) {
		printk(KERN_WARNING "Kdump: Kdump buffer page not"
		" allocated\n");
		kunmap_atomic(vaddr);
		return -EFAULT;
		}
		copy_page(kdump_buf_page, vaddr);
		kunmap_atomic(vaddr);
		if (copy_to_user(buf, (kdump_buf_page + offset), csize))
		return -EFAULT;
		}

		return csize;
		if (copy_to_user(buf, vaddr + offset, csize))
		csize = -EFAULT;
		}

		static int __init kdump_buf_page_init(void)
		{
		int ret = 0;

		kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
		if (!kdump_buf_page) {
		printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
		" page\n");
		ret = -ENOMEM;
		}
		kunmap_local(vaddr);

		return ret;
		return csize;
		}
		arch_initcall(kdump_buf_page_init);

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