fs/proc/kcore: pfn_is_ram check only applies to KCORE_RAM
Let's resturcture the code, using switch-case, and checking pfn_is_ram() only when we are dealing with KCORE_RAM. Link: https://lkml.kernel.org/r/20210526093041.8800-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Aili Yao <yaoaili@kingsoft.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Jiri Bohac <jbohac@suse.cz> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Roman Gushchin <guro@fb.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Steven Price <steven.price@arm.com> Cc: Wei Liu <wei.liu@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -483,25 +483,36 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
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goto out;
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}
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m = NULL; /* skip the list anchor */
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} else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
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if (clear_user(buffer, tsz)) {
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ret = -EFAULT;
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goto out;
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}
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} else if (m->type == KCORE_VMALLOC) {
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goto skip;
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}
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switch (m->type) {
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case KCORE_VMALLOC:
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vread(buf, (char *)start, tsz);
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/* we have to zero-fill user buffer even if no read */
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if (copy_to_user(buffer, buf, tsz)) {
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ret = -EFAULT;
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goto out;
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}
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} else if (m->type == KCORE_USER) {
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break;
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case KCORE_USER:
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/* User page is handled prior to normal kernel page: */
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if (copy_to_user(buffer, (char *)start, tsz)) {
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ret = -EFAULT;
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goto out;
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}
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} else {
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break;
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case KCORE_RAM:
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if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
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if (clear_user(buffer, tsz)) {
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ret = -EFAULT;
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goto out;
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}
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break;
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}
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fallthrough;
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case KCORE_VMEMMAP:
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case KCORE_TEXT:
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if (kern_addr_valid(start)) {
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/*
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* Using bounce buffer to bypass the
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@ -525,7 +536,15 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
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goto out;
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}
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}
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break;
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default:
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pr_warn_once("Unhandled KCORE type: %d\n", m->type);
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if (clear_user(buffer, tsz)) {
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ret = -EFAULT;
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goto out;
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}
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}
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skip:
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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