vmcore: convert __read_vmcore to use an iov_iter
This gets rid of copy_to() and let us use proc_read_iter() instead of proc_read(). Link: https://lkml.kernel.org/r/20220408090636.560886-3-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle)
akpm
Родитель
5d8de293c2
Коммит
4a22fd2037
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@ -249,22 +249,8 @@ ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter,
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return copy_oldmem_page(iter, pfn, csize, offset);
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}
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/*
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* Copy to either kernel or user space
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*/
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static int copy_to(void *target, void *src, size_t size, int userbuf)
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{
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if (userbuf) {
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if (copy_to_user((char __user *) target, src, size))
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return -EFAULT;
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} else {
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memcpy(target, src, size);
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}
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return 0;
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}
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#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
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static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
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static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size)
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{
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struct vmcoredd_node *dump;
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u64 offset = 0;
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@ -277,14 +263,13 @@ static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
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if (start < offset + dump->size) {
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tsz = min(offset + (u64)dump->size - start, (u64)size);
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buf = dump->buf + start - offset;
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if (copy_to(dst, buf, tsz, userbuf)) {
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if (copy_to_iter(buf, tsz, iter) < tsz) {
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ret = -EFAULT;
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goto out_unlock;
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}
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size -= tsz;
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start += tsz;
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dst += tsz;
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/* Leave now if buffer filled already */
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if (!size)
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@ -340,33 +325,28 @@ out_unlock:
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/* Read from the ELF header and then the crash dump. On error, negative value is
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* returned otherwise number of bytes read are returned.
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*/
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static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
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int userbuf)
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static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
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{
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ssize_t acc = 0, tmp;
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size_t tsz;
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u64 start;
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struct vmcore *m = NULL;
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if (buflen == 0 || *fpos >= vmcore_size)
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if (!iov_iter_count(iter) || *fpos >= vmcore_size)
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return 0;
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/* trim buflen to not go beyond EOF */
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if (buflen > vmcore_size - *fpos)
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buflen = vmcore_size - *fpos;
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iov_iter_truncate(iter, vmcore_size - *fpos);
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/* Read ELF core header */
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if (*fpos < elfcorebuf_sz) {
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tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
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if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
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tsz = min(elfcorebuf_sz - (size_t)*fpos, iov_iter_count(iter));
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if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz)
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return -EFAULT;
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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acc += tsz;
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/* leave now if filled buffer already */
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if (buflen == 0)
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if (!iov_iter_count(iter))
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return acc;
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}
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@ -387,35 +367,32 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
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/* Read device dumps */
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if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
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tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
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(size_t)*fpos, buflen);
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(size_t)*fpos, iov_iter_count(iter));
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start = *fpos - elfcorebuf_sz;
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if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
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if (vmcoredd_copy_dumps(iter, start, tsz))
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return -EFAULT;
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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acc += tsz;
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/* leave now if filled buffer already */
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if (!buflen)
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if (!iov_iter_count(iter))
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return acc;
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}
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#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
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/* Read remaining elf notes */
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tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
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tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos,
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iov_iter_count(iter));
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kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
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if (copy_to(buffer, kaddr, tsz, userbuf))
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if (copy_to_iter(kaddr, tsz, iter) < tsz)
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return -EFAULT;
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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acc += tsz;
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/* leave now if filled buffer already */
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if (buflen == 0)
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if (!iov_iter_count(iter))
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return acc;
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}
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@ -423,19 +400,17 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
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if (*fpos < m->offset + m->size) {
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tsz = (size_t)min_t(unsigned long long,
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m->offset + m->size - *fpos,
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buflen);
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iov_iter_count(iter));
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start = m->paddr + *fpos - m->offset;
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tmp = read_from_oldmem(buffer, tsz, &start,
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userbuf, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
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tmp = read_from_oldmem_iter(iter, tsz, &start,
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cc_platform_has(CC_ATTR_MEM_ENCRYPT));
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if (tmp < 0)
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return tmp;
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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acc += tsz;
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/* leave now if filled buffer already */
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if (buflen == 0)
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if (!iov_iter_count(iter))
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return acc;
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}
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}
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@ -443,15 +418,14 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
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return acc;
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}
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static ssize_t read_vmcore(struct file *file, char __user *buffer,
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size_t buflen, loff_t *fpos)
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static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter)
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{
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return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
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return __read_vmcore(iter, &iocb->ki_pos);
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}
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/*
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* The vmcore fault handler uses the page cache and fills data using the
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* standard __vmcore_read() function.
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* standard __read_vmcore() function.
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*
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* On s390 the fault handler is used for memory regions that can't be mapped
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* directly with remap_pfn_range().
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@ -461,9 +435,10 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
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#ifdef CONFIG_S390
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struct address_space *mapping = vmf->vma->vm_file->f_mapping;
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pgoff_t index = vmf->pgoff;
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struct iov_iter iter;
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struct kvec kvec;
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struct page *page;
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loff_t offset;
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char *buf;
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int rc;
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page = find_or_create_page(mapping, index, GFP_KERNEL);
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@ -471,8 +446,11 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
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return VM_FAULT_OOM;
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if (!PageUptodate(page)) {
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offset = (loff_t) index << PAGE_SHIFT;
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buf = __va((page_to_pfn(page) << PAGE_SHIFT));
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rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
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kvec.iov_base = page_address(page);
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kvec.iov_len = PAGE_SIZE;
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iov_iter_kvec(&iter, READ, &kvec, 1, PAGE_SIZE);
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rc = __read_vmcore(&iter, &offset);
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if (rc < 0) {
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unlock_page(page);
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put_page(page);
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@ -722,7 +700,7 @@ static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
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static const struct proc_ops vmcore_proc_ops = {
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.proc_open = open_vmcore,
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.proc_read = read_vmcore,
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.proc_read_iter = read_vmcore,
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.proc_lseek = default_llseek,
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.proc_mmap = mmap_vmcore,
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};
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